ashfordeOU
User🚀 The aerospace knowledge layer for AI agents — 784 verified skills in 86 installable packs across 12 engineering families, mapped to 30 standards (ECSS · DO-178C · NASA) and proven by a 1536-task deterministic gate battery. AgentSkills.io format · Apache-2.0 · by Ashforde OÜ
Categories
Indexed Skills (77)
aeroelastic-gust-response
Use when you must compute the dynamic aeroelastic response of a flexible two-degree-of-freedom typical wing section to a discrete gust with indicial unsteady aerodynamics: run the Wagner and Kussner lag-state lift model in the time domain, produce the plunge and pitch response histories for a one-minus-cosine gust, and report the dynamic magnification factor of the peak lift over the quasi-steady value plus the peak-load verdict against a limit. Produces response histories, the dynamic magnification factor, and load margin. Trigger: aeroelastic gust response, dynamic gust response, kussner function, wagner function, indicial aerodynamics, dynamic magnification factor, typical section gust, gust response history.
divergence-speed
Use when you must compute the static aeroelastic divergence condition of a lifting surface: calculate the divergence dynamic pressure from the torsional stiffness, the reference area, the chord, the lift curve slope, and the aerodynamic-center-to-shear-center offset ratio, convert it to the divergence speed at sea level, and assess the divergence margin against the design dive speed, flagging risk when the margin falls below the required 1.15 threshold. Produces the divergence dynamic pressure, the divergence speed, and a margin verdict that feed torsional stiffness sizing for divergence clearance. Trigger: divergence speed, divergence dynamic pressure, torsional stiffness, aerodynamic center, shear center, divergence margin, static aeroelastic divergence.
flutter-speed-prediction
Use when the task is classical wing flutter of the two-DOF typical section, the V-g method, damping crossing, frequency coalescence, or flutter clearance. Compute the classical flutter speed of a two-degree-of-freedom bending-torsion wing section: build the typical section with plunge and pitch about the elastic axis, apply Theodorsen unsteady aerodynamics with the complex lift-deficiency function C(k), run the V-g method across the reduced frequency range, locate the flutter speed where the artificial structural damping g crosses zero, check frequency coalescence near the flutter boundary, and assess the flutter margin against the design dive speed in the FAR 25.629 clearance context. Produces the flutter speed, flutter frequency, reduced frequency, coalescence verdict, and a clearance margin assessment. Trigger: flutter speed, v-g method, bending-torsion flutter, frequency coalescence, typical section, flutter margin, far 25.629.
airfoil-geometry
Use when you must work with classic NACA airfoil geometry: decode NACA 4-digit, 5-digit, and 6-series designations into camber, camber position, and thickness; compute the 4-digit thickness distribution, mean camber line ordinates and slope; and derive leading-edge radius and section area from the public-domain NACA formulas. Produces the geometry parameters that feed section selection, structural depth checks, and coordinate generation for panel or CFD analysis. Trigger: naca airfoil, camber, thickness distribution, mean line, leading edge radius, section area, airfoil coordinates.
xfoil-analysis
Use when running XFOIL-style airfoil analysis for a given section: plan viscous and inviscid polar runs, validate lift and drag coefficient points against physical plausibility bands, and check NACA 0012 results at Reynolds number 6 million against the classic wind-tunnel anchor (lift coefficient about 0.82 at 10 degrees, zero-lift drag about 0.0079). Distinguishes inviscid runs (drag meaningless) from viscous runs and flags high-drag cases needing transition or mesh-density checks. Trigger: xfoil, airfoil, polar, lift coefficient, drag coefficient, naca, viscous analysis, reynolds number, transition.
boundary-layer-theory
Use when the task is boundary-layer thickness estimation, displacement or momentum thickness, skin-friction coefficient on a surface, Reynolds-number regime classification, or transition location on a smooth surface. Compute laminar and turbulent boundary-layer thicknesses for a smooth flat plate: estimate the 99-percent thickness, displacement thickness, and momentum thickness from the local Reynolds number with the Blasius and 1/7 power-law correlations, evaluate the local and average skin-friction coefficients, and classify the flow into laminar or turbulent regimes by the transition Reynolds number. Trigger: boundary layer, displacement thickness, momentum thickness, skin friction, transition, Reynolds number, Blasius.
cfd-mesh-generation
Use when the task is CFD mesh generation, grid type selection, prism layer setup, near-wall resolution, domain sizing, or cell quality checking for a solver run. Generate a CFD mesh for an aerospace flow case: choose between structured, unstructured, and hybrid grids, size the near-wall first cell height from a y plus target and skin friction coefficient, build boundary-layer prism layers with a growth ratio, flag cell quality with skewness, orthogonality, and aspect ratio checks, size the far-field domain, and plan refinement levels. Produces the grid type recommendation, first cell height, prism layer count, quality verdict, cell count estimate, and refinement plan. Trigger: mesh generation, grid types, prism layers, first cell height, skewness, orthogonality, aspect ratio, domain size, mesh refinement.
cfd-turbulence-modeling
Use when you must estimate the wall-normal first cell height for a CFD mesh: compute the y plus value from the friction velocity and kinematic viscosity, derive the friction velocity from the wall shear stress or the skin friction coefficient, and recommend the turbulence model and wall treatment for the boundary layer. Produces the y plus value, the friction velocity, and the turbulence model recommendation that size the near-wall mesh. Trigger: turbulence model, y plus, friction velocity, boundary layer, wall treatment, cfd.
cfd-validation
Use when you must validate a computational fluid dynamics result against authoritative reference data: select the validation case for the flow regime and application (NACA 0012 or NACA 4412 airfoil, ONERA M6 transonic wing, DLR-F6 transport wing-body, flat plate boundary layer), compute the relative error, RMS error and max local error, run a Richardson extrapolation grid convergence check, judge pass or fail against tolerance bands, and estimate validation uncertainty. Produces the validation verdict and a validation report skeleton. Trigger: cfd validation, validation case selection, richardson extrapolation, grid convergence, naca 0012 drag, onera m6, dlr f6, error metrics, validation uncertainty, validation report.
panel-method
Use when the task is panel method setup, source or doublet panels, Neumann or Dirichlet boundary conditions, Kutta condition enforcement, pressure distribution on an airfoil or fuselage, or potential flow over 3D bodies. Compute the surface pressure distribution and force coefficients for an airfoil or body in incompressible potential flow with a panel method: build panel geometry from a closed point list, assemble the source panel influence matrix for the Neumann boundary condition, assemble the doublet panel influence matrix for the Dirichlet boundary condition, solve the linear system, evaluate the surface velocity and pressure coefficient, integrate pressure for lift and drag, and apply the Kutta condition to fix trailing-edge circulation. Trigger: panel method, source panel, doublet panel, kutta condition, neumann boundary condition, dirichlet boundary condition, pressure coefficient, potential flow, 3d body.
vortex-lattice-method
Use when you must compute the spanwise loading of a straight trapezoidal wing with the vortex lattice method: build the horseshoe vortex panel lattice at the quarter chord, assemble the influence coefficient matrix at the three-quarter chord control points, solve the linear system for the panel circulations, and derive the spanwise lift distribution, the downwash angles, and the induced drag. Produces the circulation solution, the per-panel lift, and the lift and induced drag coefficients that gate wing aerodynamic efficiency estimates. Trigger: vortex lattice method, horseshoe vortex, panel lattice, influence coefficients, spanwise lift distribution, downwash angle, induced drag, Trefftz plane.
drag-polar
Use when you must compute the parabolic drag-polar of a wing from the zero-lift-drag coefficient cd0, the Oswald span-efficiency, and the aspect-ratio: calculate the induced-drag factor k with k = 1 / (pi * e * AR), the drag coefficient at a given lift coefficient, the lift-to-drag ratio at a point, and the maximum lift-to-drag ratio with its optimal lift coefficient. Also fit a parabolic drag-polar to two measured lift and drag points to recover cd0 and k. Produces the fitted polar coefficients and the peak performance values that gate the wing aerodynamic efficiency assessment. Trigger: drag-polar, parabolic, Oswald span-efficiency, induced-drag factor, aspect-ratio, cd0, lift-to-drag, max L/D, polar fit.
lift-curve-slope
Use when you must estimate the lift curve slope of a wing from section data: compute the thin-airfoil section slope a0 = 2*pi per radian, correct it for finite aspect ratio with the lifting-line formula a = a0 / (1 + a0 / (pi * e * AR)), apply the simple sweep theory cosine correction, apply the Prandtl-Glauert Mach correction a / sqrt(1 - M^2) with a documented M < 0.7 limit, and predict lift coefficient from angle of attack with C_L = a * (alpha - alpha_zero), including an optional stall guard. Produces the corrected wing slope and lift coefficient for a given angle of attack that feed wing sizing and performance estimates. Trigger: lift curve slope, thin-airfoil theory, finite wing correction, aspect ratio, sweep correction, Prandtl-Glauert, lift coefficient.
parasite-drag
Use when the task is drag buildup, zero-lift drag estimation, the wetted-area method, skin-friction coefficients, form factor, interference factor, or equivalent skin-friction coefficient in a preliminary drag assessment. Estimate the parasite (zero-lift) drag of a fixed-wing aircraft with the component buildup method: compute the flat-plate skin-friction coefficient from the Reynolds number for laminar and turbulent flow, apply the form factor and interference factor to each component, convert the wetted area into a drag coefficient, and sum the wing, fuselage, nacelle, and tail contributions into the total parasite drag. Also back out the equivalent skin-friction coefficient from the total wetted area and the total drag. Trigger: parasite drag, zero-lift drag, skin friction, wetted area, form factor, interference factor, drag buildup, Reynolds number.
ground-effect
Use when you must estimate the ground effect on a wing operating near the ground: compute the induced drag reduction factor and the induced drag ratio from the height to span ratio, apply the image vortex correction to the downwash and the effective aspect ratio, and estimate the lift increase and lift curve slope change in ground effect for takeoff and landing analysis. Produces the ground effect factor, the corrected induced drag, and the lift curve slope that feed low altitude performance estimates. Trigger: ground effect, induced drag reduction, image vortex, height to span ratio, ground cushion, takeoff lift.
high-lift-systems
Use when the task is high-lift device selection, flap clmax estimation, slat contribution, wing CLmax, or stall speed with flaps. Estimate high-lift system performance for conceptual design: compute the section clmax increment for trailing-edge flaps (plain, split, slotted, Fowler) and leading-edge devices (slat, Krueger), scale the increment with deflection, flap chord ratio, and flapped span fraction, combine flap and slat increments by superposition, apply the three-dimensional and sweep reduction to get wing CLmax, and derive the resulting stall speed. Produces the wing maximum lift coefficient, stall speed, drag increment, and pitching moment increment that size the flap schedule and drive field performance estimates. Trigger: high-lift, flap, slat, Fowler, Krueger, clmax, stall speed, lift increment.
normal-shock
Use when you must compute normal shock relations for compressible flow: find the downstream Mach number, static pressure, density, and temperature ratios across the shock, and the stagnation pressure loss from the upstream Mach number. Produces the five shock ratios that gate inlet and high-speed aerodynamic analysis of a supersonic flow. Trigger: normal shock, oblique shock, mach number, compressible flow, pressure ratio, stagnation pressure, supersonic inlet, shock relations.
oblique-shock
Use when you must analyze an oblique shock in supersonic compressible flow: compute the wave angle beta from the upstream Mach number M1 and the flow deflection angle theta with the theta-beta-M relation, find the weak and strong solutions, the maximum deflection angle for an attached shock, and the downstream Mach number, static pressure, density, temperature, and stagnation pressure ratios across the shock. Covers shock polar basics: the weak branch keeps the flow supersonic with little stagnation pressure loss, the strong branch goes subsonic, and a deflection above the limit detaches the shock. Produces the wave angle, downstream state, and deflection limit for wedge, compression-corner, and inlet analyses. Trigger: oblique shock, shock wave, wave angle, deflection angle, theta-beta, wedge, compression corner, detached shock, shock polar, weak solution, strong solution, supersonic flow.
prandtl-meyer
Use when you must compute Prandtl-Meyer expansion relations for supersonic compressible flow: derive the expansion angle from the Mach number, find the downstream Mach number after the flow turns away from itself by a given angle, compute the total turning angle across the expansion fan, and the static pressure ratio across it. Produces the Prandtl-Meyer angle, the downstream Mach number, the turning angle, and the pressure ratio that gate supersonic airfoil, inlet, and nozzle analysis. Trigger: prandtl-meyer, expansion fan, mach number, supersonic flow, turning angle, compressible flow.
shock-expansion-airfoil
Use when you must compute the supersonic shock-expansion solution for a diamond (double-wedge) airfoil section: patch oblique-shock and Prandtl-Meyer relations over the four planar surfaces at a freestream Mach number and angle of attack, then integrate the panel pressures into the section lift, wave drag, and leading-edge moment coefficients with a surface pressure table. Implements theta-beta-M (weak solution), oblique-shock ratios, and the Prandtl-Meyer function internally for the turn-by-turn surface states. Produces cl, cd_wave, cm_le and per-surface Cp for a given half-angle, angle of attack, and Mach number. Trigger: shock-expansion, supersonic airfoil, diamond airfoil, double-wedge, surface-pressure integration, wave drag coefficient.
supercritical-airfoil
Use when you must analyze or design a supercritical airfoil for high-speed flight: compute the drag-divergence Mach number from the Korn thickness-lift rule, estimate the terminating shock strength of the upper-surface supersonic pocket, quantify the wave-drag penalty above drag divergence, and size the maximum thickness ratio or cruise lift coefficient that the flat upper surface permits. Produces the drag-divergence Mach, the shock-strength reduction, the wave-drag penalty, and the aft-loading pitching moment that feed high-speed wing design. Trigger: supercritical airfoil, drag divergence Mach, aft loading, flat upper surface, wave drag, shock strength.
swept-wing-aerodynamics
Use when you must apply wing sweep effects for high-speed aerodynamics: compute the simple sweep theory cosine corrections for the lift curve slope and the section Mach number, find the effective Mach number and the velocity components normal and tangential to the leading edge, and estimate the critical Mach number increase that sweep provides over the unswept wing. Produces the swept wing lift slope, the effective Mach number, and the critical Mach estimate that feed transonic cruise and high-speed wing design. Trigger: swept wing, sweep angle, leading edge sweep, simple sweep theory, critical Mach, effective Mach.
transonic-similarity
Use when you must apply compressibility corrections to subsonic aerodynamic coefficients: compute the Prandtl-Glauert factor and the refined Karman-Tsien correction for the pressure coefficient at a given Mach number, evaluate the transonic similarity parameter linking thickness and sweep effects, and estimate the critical Mach number at which local flow first reaches sonic speed. Produces corrected pressure coefficients and corrected lift slope, the critical Mach estimate, and drag-divergence Mach guidance for airfoil selection and high-subsonic wing design. Trigger: compressibility correction, Prandtl-Glauert, Karman-Tsien, transonic similarity, critical Mach number, pressure coefficient.
wave-drag-area-rule
Use when the task is wave drag estimation, area ruling, Sears-Haack bodies, drag divergence, or cross-sectional area distribution in transonic design. Compute transonic wave drag with the Whitcomb area rule: build the streamwise cross-sectional area distribution of a wing-body combination, size the Sears-Haack minimum-drag body for a given length and volume, evaluate its zero-lift wave drag, and estimate the drag-divergence Mach number and the parabolic wave drag rise above it. Produces the Sears-Haack radius and area distributions, the equivalent drag area, the wave drag coefficient and force, and the area-rule fuselage pinch that smooths the total area distribution. Trigger: wave drag, area rule, Sears-Haack, drag divergence, cross-sectional area.
aerodynamics
Use when a task concerns aerodynamics: guide the router to the aerodynamics pack: airfoil-selection family choice, xfoil-analysis polars, airfoil-geometry NACA geometry, airfoil-optimization shape trade, cfd-convergence residuals, cfd-turbulence-modeling model selection, cfd-mesh-generation grids and y-plus, vortex-lattice-method VLM, panel-method potential flow, normal-shock shock relations, oblique-shock theta-beta-M, prandtl-meyer expansions, swept-wing-aerodynamics sweep, transonic-similarity Karman-Tsien, supercritical-airfoil aft loading, wave-drag-area-rule area rule, drag-polar polar, parasite-drag zero-lift drag, lift-curve-slope lift slope, boundary-layer-theory flat-plate layers, ground-effect in-ground lift, high-lift-systems flap and slat clmax. Trigger: aerodynamics, airfoil, polar, drag polar, sweep, Mach, boundary layer, ground effect, high lift, vortex lattice, panel method, transonic.
windtunnel-data-reduction
Use when the task is experimental wind tunnel data reduction, tare or blockage correction, wall interference, dynamic pressure correction, coefficient reduction, or uncertainty from repeated runs. Correct wind tunnel balance and pressure measurements into standard aerodynamic coefficients: subtract support tare and tareshift, apply solid and wake blockage corrections, correct wall interference and streamline curvature, apply Reynolds number and Mach corrections, estimate repeat-run uncertainty of the measured coefficients, and reduce raw runs to lift, drag, and pitching moment coefficients plus pressure distributions referenced to planform area and reference length, with a full correction ledger. Trigger: windtunnel data reduction, tare correction, blockage correction, wall interference, reynolds correction, aerodynamic coefficients, pressure distribution, uncertainty estimation, balance data, experimental aerodynamics.
windtunnel-wall-corrections
Use when you must apply closed-wall wind tunnel corrections to measured lift and drag coefficients: compute solid blockage from model volume over the test-section volume scale with K1 = 0.52, wake blockage from the uncorrected drag coefficient, total blockage, buoyancy drag increment from the streamwise pressure gradient, lift interference and streamline curvature alpha increment, sigma factor from span over section height, and first-order corrected lift and drag coefficients with corrected q and velocity. Produces corrected coefficients, alpha, q and V for free-air comparison. Trigger: wall corrections, solid blockage, wake blockage, wind tunnel boundary interference, lift interference, buoyancy drag, test section constraint, corrected drag coefficient.
wing-planform-design
Use when you must derive the wing-planform-design reference geometry and the spanwise loading of a straight-tapered wing from the span, the area, and the taper-ratio: compute the root-chord and the tip-chord, the mean-geometric-chord, the mean-aerodynamic-chord with its mac-span-station, and convert the leading-edge-sweep into the quarter-chord-sweep. Compute the spanwise-load-distribution with the schrenk-approximation to obtain the local-lift-coefficient at any station, and size the washout-angle so the root reaches stall before the tip, giving the stall-sequencing for a benign stall. Produces the reference chords, the sweep line, and the loading check that feed the lift-curve-slope and vortex-lattice-method leaves. Trigger: wing planform design, taper ratio, mean aerodynamic chord, MAC span station, quarter chord sweep, Schrenk approximation, spanwise load distribution, washout angle.
arinc429-protocol
Use when checking a bus monitor decode, writing a test stimulus for an LRU interface, or explaining the one-transmitter up-to-20-receivers twisted shielded pair topology. Encode and decode ARINC 429 digital information transfer words for avionics data buses: build the 32-bit word from the octal label, SDI, 19-bit data field, SSM, and odd parity bit, split a received word back into its fields, and convert BNR and BCD parameters to and from engineering units at the word rate of 12.5 or 100 kbps. Trigger: ARINC 429, data word, octal label, SDI, SSM, parity, BNR, BCD, 100 kbps, 12.5 kbps, avionics data bus.
arinc664-afdx
Use when sizing an AFDX network, writing a virtual link configuration table, or reviewing a network design against bandwidth, jitter, and latency budgets for certification. Size and validate ARINC 664 Part 7 Avionics Full-Duplex Switched Ethernet (AFDX) network configurations for civil avionics: compute virtual link bandwidth from the BAG and the maximum frame size, check that the virtual link set fits the 100 Mbps link, bound frame transmission time, verify jitter against the tolerance, estimate end-to-end latency through the switched network, and select the largest legal BAG that still delivers a required bandwidth. Trigger: AFDX, ARINC 664, virtual link, BAG, jitter, end system, avionics network, switched ethernet.
mil-std-1553
Use when the task is a MIL-STD-1553 command word, status word, data word, Manchester II encoding, bus controller or remote terminal behavior, or military avionics data bus design. Encode and decode MIL-STD-1553B avionics data bus words for the 1 Mbps command/response multiplex bus: build the 20-bit command word from the 5-bit remote terminal address, transmit/receive bit, 5-bit subaddress, and 5-bit word count with odd parity, split a received word back into its fields, classify the message format (BC-to-RT, RT-to-BC, RT-to-RT, broadcast, mode code), and lay out dual redundant bus A/B operation with bus controller and remote terminal message scheduling. Trigger: mil-std-1553, 1553, command-response, remote-terminal, bus controller, dual redundant, Manchester II, mode code, 1 Mbps.
electrostatic-discharge
Use when planning or auditing ESD qualification of LRUs and cabin equipment that personnel handle during normal operation or maintenance. Determine DO-160 Section 25 electrostatic discharge (ESD) test parameters for airborne equipment: select the single equipment category and 15 kV air discharge test level, compute the stored energy and discharge waveform currents (peak, 30 ns, 60 ns) from the 150 pF and 330 ohm generator model, check the 10 positive and 10 negative discharges per test point, and judge test point applicability from personnel accessibility with connector pins excluded. Verdict logic classifies pass criteria; input validation and summary formulas only, no standard tables reproduced. Trigger: electrostatic discharge, ESD testing, air discharge, discharge waveform, test point.
environmental-qualification
Use when planning or reviewing DO-160 environmental qualification of airborne equipment: map equipment categories to applicable test-condition sections (temperature, altitude, humidity, vibration, EMC, lightning, and others), verify that the planned test matrix covers every required section, and check operating-temperature ranges per equipment category. Section names and typical category temperature ranges are provided as reference data, with category-specific exclusions to be confirmed against the current revision; all logic is deterministic, offline stdlib. Trigger: DO-160, environmental qualification, test conditions, temperature, altitude, vibration, EMC, lightning, humidity, equipment category.
power-input
Use when reviewing a power-input test plan, analyzing captured input-power waveforms against the equipment category, or deciding whether a transient event stays within its category envelope. Assess DO-160 Section 16 power-input characteristics of airborne equipment: verify measured AC and DC steady-state voltages against normal and emergency limits, compute voltage-sag depth and voltage-surge height as percentages of nominal, check frequency-variation tolerance for 400 Hz AC buses, and verify transient-recovery time after a sag or surge event. Trigger: DO-160, power-input, voltage-sag, voltage-surge, frequency-variation, transient-recovery, emergency-power.
radio-frequency-emissions
Use when you must plan and check the DO-160 section 21 radio frequency emission test of airborne equipment: convert the measured conducted emission amplitude from volts to dBuV and the radiated emission field to dBuV/m at the antenna, classify the equipment installation category, apply the CE102 conducted emission limit curve and the RE102 radiated emission limit curve for the category, compute the emission margin at each frequency, find the worst case frequency, and judge the equipment pass or fail for the EMC qualification. Produces the emission margin, the worst case frequency, and the pass or fail verdict that gate the DO-160 EMC qualification. Trigger: radio frequency emissions, DO-160 section 21, conducted emissions, radiated emissions, CE102, RE102, emission limit, emission margin, dBuV, dBuV/m, EMC qualification.
radio-frequency-susceptibility
Use when you must plan and execute a DO-160 section 20 radio frequency susceptibility (RF immunity) test on airborne equipment: compute the radiated field strength from amplifier power, antenna gain, and distance; size the amplifier power budget for a required field level including cable loss and calibration margin; convert between V/m and dBuV/m, A and dBuA, and W and dBm; estimate the AM-modulated peak field and average power; and check conducted immunity margins against CS114 category current limits. Produces the field strength, the amplifier power budget, and the pass-fail margins that gate RF immunity test planning. Trigger: radio frequency susceptibility, RS103, CS114, radiated immunity, conducted immunity, field strength, RF test, amplifier power.
development
Use when you must develop DO-178C airborne software lifecycle data for avionics items: capture high-level and low-level requirements, maintain bidirectional requirement-to-code trace links, identify derived requirements, and apply design/coding standards scaled to software level. Produce development-phase artifacts (requirements, design, code, trace matrix) for verification, with traceability closure and independent review at levels A and B. Ensure protection and safety assurance trace from top-level system protection needs down to low-level implementation and code, and maintain full coverage of verification results against each requirement and design element. Track verification coverage depth linking each test, analysis, or review outcome to originating requirements. Trigger: DO-178C development, requirements traceability, protection trace, protection assurance, safety assurance trace, verification coverage, derived requirements, low-level requirements, coding standards, software design, lifecycle data.
software-testing
Generate requirements-based-testing test cases for DO-178C airborne software and count the test cases each structural-coverage metric demands: statement coverage needs 1 case per statement, decision coverage 2 cases per decision, and mc-dc needs n+1 cases for a compound boolean condition with n independent terms. Use when a task asks how many test cases a boolean condition requires, how to derive tests from high-level and low-level requirements, which coverage objectives apply per software level (level A requires mc-dc, B decision coverage, C statement coverage, D and E none), or how to measure and document structural coverage against the DO-178C Table A-7 objectives. Trigger: requirements-based-testing, mc-dc test-case-count, structural-coverage measurement, coverage-objectives per level, test case generation.
tool-qualification
Use when assessing software tool qualification per DO-330 and DO-178C: determine the tool qualification level (TQL-1 through TQL-5) from the applicable tool criteria, check that a qualification level meets the required rigor, select the governing criterion when several apply, and validate that tool operational requirements (TOR) and qualification artifacts are complete. DO-330 tool criteria 1-5 map to TQL-1..TQL-5 with lower numbers meaning stricter rigor; all logic is deterministic, offline stdlib. Trigger: tool qualification, DO-330, TQL, tool criteria, qualification level, tool operational requirements, TOR, tool credit, verification tool.
hardware-planning
Use when you must plan DO-254 design assurance for airborne electronic hardware: classify an item as simple or complex AEH, scope the plan for hardware aspects of certification (PHAC) and the hardware design assurance data, and plan requirements capture, verification, and configuration management for the item. Complex AEH (programmable logic, processors, or designs whose correct behavior cannot be fully established from top-level data alone) follows the full design assurance process; simple AEH uses a reduced but still planned process. Trigger: DO-254 hardware planning, airborne electronic hardware, PHAC, simple vs complex hardware, hardware design assurance, programmable logic.
boundary-layer-transition
Use when you must predict the laminar-turbulent transition location on a two-dimensional body from its edge-velocity distribution: grow the laminar boundary layer with the Thwaites integral relation to obtain the boundary-layer momentum deficit at each station, build the local Reynolds numbers from the edge velocity and that deficit, evaluate the Michel transition criterion against them, and interpolate the first station where the criterion is crossed to give the transition location. Produces the Reynolds-number history along the body, the Michel criterion margin at each station, and the transition location that gates a natural-transition estimate for an airfoil or body. Trigger: boundary-layer-transition, transition-location, thwaites-integral, michel-criterion, natural-transition, edge-velocity distribution, laminar-turbulent transition, airfoil transition onset.
aerodynamic-heating
Use when you must estimate the aerodynamic heating at the stagnation point of a hypersonic body: stagnation-point convective heat flux from the Sutton-Graves correlation using freestream density, flight velocity and nose radius, radiation-equilibrium wall temperature from the Stefan-Boltzmann balance at a chosen surface emissivity, and the nose-radius bluntness trade that scales the flux for blunt versus sharp geometries. Produces the stagnation heat flux, the radiation-equilibrium temperature and the bluntness comparison that gate a thermal protection material choice. Trigger: aerodynamic heating, stagnation-point-heating, sutton-graves, radiation-equilibrium-temperature, nose-radius-bluntness, reentry heating, thermal protection.
hypersonic-flow
Use when you must estimate aerodynamic forces on a body in hypersonic flow with modified Newtonian impact theory: stagnation pressure behind the normal shock (Rayleigh pitot relation), the finite-Mach stagnation pressure coefficient, local pressure by the Newtonian sine-squared law, the hypersonic vacuum limit on shadowed surfaces, and integrals over a sphere, cone and flat plate giving sphere drag, cone axial force, and flat plate lift, drag and lift-to-drag ratio. Produces the stagnation Cp and body force coefficients. Trigger: hypersonic flow, modified Newtonian theory, Newtonian impact pressure, stagnation pressure coefficient, blunt body drag, sphere drag coefficient, cone axial force, hypersonic vacuum limit.
wind-tunnel-model-design
Use when you must design the wind tunnel model and the test setup for a wind tunnel campaign on an aircraft configuration: select the model scale as the smaller of the test section blockage limit and the span clearance, compute the model wing area, span and mean aerodynamic chord from the scale, check the model Reynolds number at the maximum tunnel speed against the full scale flight Reynolds number and report the Reynolds mismatch, estimate the maximum dynamic pressure and the model load at the maximum test lift coefficient, rate the force balance capacity against that load, and size the model support sting for the bending moment. Produces the chosen scale, model reference dimensions, blockage ratio, Reynolds ratio, balance verdict and sting diameter that gate the model build. Trigger: wind tunnel model design, model scale selection, blockage ratio, reynolds mismatch, force balance rating, sting sizing, test section.
winglet-design
Use when you must size a winglet as a wingtip device for induced-drag reduction on a fixed-wing aircraft: compute the effective span extension and the effective aspect ratio from the winglet height fraction and the cant angle, estimate the improved span efficiency, the induced-drag factor and the induced-drag coefficient at a reference lift coefficient, the percent drag reduction, and the root bending moment penalty at the wing root, then size the winglet height by bisection to hit a target drag reduction. Produces the winglet height, the effective aspect ratio, the drag reduction and the bending penalty that gate the wingtip device trade. Trigger: winglet design, wingtip device, induced drag reduction, effective aspect ratio, span efficiency, cant angle, winglet height, root bending moment penalty.
data-control-coupling-analysis
Use when you must analyze data coupling and control coupling between airborne software components: identify the data-coupling items between component pairs from their written and read variable sets with declared synchronization suppression, identify the control-coupling items across call edges where a caller-written variable is read by the callee, compute the coupling coverage ratio against declared evidence, and return the PASS or FAIL verdict with the uncovered item list. Produces the data-coupling item list, the control-coupling item list, the coupling coverage ratio and the evidence verdict that gate the level A inter-component coupling objective. Trigger: data coupling analysis, control coupling analysis, shared-variable pairs, call-edge coupling items, coupling coverage evidence, level-a coupling objectives, inter-component coupling.
boundary-layer-separation
Use when you must predict boundary layer separation: grow the laminar layer with the Thwaites integral along the edge-velocity distribution of a two-dimensional body, flag the first station where the thwaites lambda parameter crosses minus 0.09 to give the laminar separation point, and apply the Stratford pressure-recovery criterion to the pressure-coefficient distribution to estimate the turbulent separation station and the separation margin below the 0.35 threshold. Produces the laminar separation station or none, the turbulent separation station or none, and the margin that gates airfoil and inlet-duct design checks. Trigger: boundary-layer-separation, thwaites-lambda-criterion, stratford-separation-criterion, laminar separation point, turbulent separation station, separation margin, adverse pressure gradient, pressure recovery, edge-velocity distribution.
delta-wing-vortex-lift
Use when you must estimate the vortex lift of a sharp-edged delta wing: apply the Polhamus leading-edge suction analogy to split the total lift into the attached potential term Kp sin(alpha) cos^2(alpha) and the leading-edge-separation vortex term Kv cos(alpha) sin^2(alpha), with the slender-wing potential slope Kp = pi AR / 2 and the vortex factor Kv growing linearly from 3.14 at AR 0 to about 3.45 at AR 4. Produces the total lift coefficient, the potential and vortex lift split, the vortex fraction, the drag due to lift CL tan(alpha), and the angle where vortex lift overtakes potential lift. Valid for sharp leading edges, subsonic flow, aspect ratio about 0.5 to 2.0, alpha up to about 25 degrees. Trigger: Polhamus suction analogy, leading edge suction, vortex lift, slender delta wing, nonlinear lift.
flat-plate-skin-friction-heating
Use when you must estimate the surface skin friction heating on a flat plate or vehicle skin at high Mach: it computes the recovery factor, adiabatic wall temperature, Eckert reference temperature, Sutherland viscosity, local skin friction coefficient and Reynolds-analogy heat transfer coefficient, then the cold-wall heat flux for a laminar or turbulent boundary layer. Produces the non-stagnation heating report with r, T_aw, T_star, Re_star, Cf, h_c and q_cold_wall in SI units for a thermal protection check. Trigger: recovery-factor, adiabatic-wall-temperature, cold-wall-heat-flux, reference-temperature-method, reynolds-analogy-factor, skin-friction-coefficient, turbulent-plate-heating, flat-plate-heating.
arinc429-bus-loading
Use when you must budget the ARINC 429 bus loading: sum the per-label transmission rates in labels per second into the total word rate, price each transmitted word at 36 bit-times (32 data bits plus the 4-bit gap) for the bus load in bits per second, compute the percent utilization of the 100 kbps or 12.5 kbps link, flag schedules that exceed the word-per-second capacity (about 2778 words per second at 100 kbps), and report the headroom against the common 80 percent design guideline. Produces the total word rate, bus load, percent utilization, capacity verdict, and design headroom that gate the ARINC 429 label rate table. Trigger: arinc 429 bus loading, label rate budget, percent bus utilization, word rate capacity, transmit schedule headroom, 100 kbps link.
mil-std-1553-bus-loading
Use when you must compute the MIL-STD-1553 bus loading: convert a minor-frame message schedule into wire-word counts per message type (command and status overhead plus data words), apply the fixed 24 microsecond word slot at the 1 Mbps data rate, sum the schedule time, and return the bus utilization against the minor-frame length with an 80 percent loading guideline verdict. Produces per-message wire words and time, the schedule total, the percent utilization, the headroom to the 80 percent budget, and a FITS or OVER verdict. Trigger: mil std 1553 bus loading, minor frame schedule, wire word count, bus utilization, data bus load, bc to rt, rt to bc, rt to rt, message overhead, loading headroom.
thin-airfoil-section-theory
Use when you must compute the section lift and the quarter-chord pitching moment of a thin cambered airfoil from its camber line: decompose the camber slope into the glauert-sine-series coefficients A0, A1 and A2 by trapezoid quadrature over the theta transform x = (1 - cos(theta))/2, then recover the zero-lift angle alpha_L0, the section lift coefficient cl = 2*pi*(alpha - alpha_L0), the quarter-chord pitching-moment coefficient cm_c4 = (pi/4)*(A2 - A1) and the center-of-pressure location x_cp/c = 1/4 - cm_c4/cl, for a NACA 4-digit mean line, a polynomial camber line or sampled camber stations. Produces the closed-form analytic section aerodynamics that anchor the numerical panel and viscous section tools. Trigger: glauert coefficients, zero lift angle, section pitching moment, camber line analysis, thin airfoil section.
rough-wall-skin-friction
Use when you must estimate the turbulent skin-friction on a rough flat plate: it computes the smooth-wall turbulent baseline Cf from the local Reynolds number, the friction velocity and the sand-roughness reynolds number k+; classifies the k-plus-regime as smooth, transitional or fully rough; evaluates the Schlichting fully-rough-cf correlation for the fetch; and selects the operative coefficient without iteration, the direct fully-rough value or a log-linear blend. Produces the regime class, k+ value, smooth baseline, rough or blended coefficient, operative coefficient with treatment note, and the trip-criterion verdict for roughness and trip-strip sizing on aerodynamic surfaces. Trigger: rough-wall-skin-friction, sand-roughness-height, equivalent-sand-roughness, roughness-reynolds-number, k-plus-regime, fully-rough-cf, trip-criterion, trip-strip-sizing.
stagnation-flow-boundary-layer
Use when you must size the laminar boundary layer, wall shear and skin friction at a low-speed 2-D or axisymmetric stagnation point or leading edge: compute the potential-flow stagnation velocity gradient from the body radius and freestream speed (factor 2 in the Hiemenz 2-D regime, 1.5 in the Homann axisymmetric regime), the 99-percent laminar boundary-layer thickness about 2.4 sqrt(nu/a), the wall shear from the Hiemenz or Homann similarity wall-shear constant, and the skin-friction coefficient against the freestream dynamic pressure. Produces the a, delta, tau_w and Cf report that gates spinner, radome, wing and fin leading-edge boundary-layer sizing at low speed. Trigger: stagnation-flow-boundary-layer, hiemenz-similarity, homann-similarity, stagnation-velocity-gradient, stagnation-wall-shear, attachment-line flow, nose boundary layer.
unsteady-laminar-stokes-layers
Use when you must compute the exact unsteady laminar Stokes layer of an infinite plate in a quiescent fluid, either impulsively started or oscillating in its own plane: for the stokes-first-problem Rayleigh layer of a plate started at speed U, evaluate the similarity profile u/U = erfc(y/(2*sqrt(nu*t))), the layer edge at 3.64*sqrt(nu*t) where u/U = 0.01, the wall shear decaying as 1/sqrt(t) from rho*U*sqrt(nu/(pi*t)), and the displacement thickness; for the stokes-second-problem oscillating-plate-layer at omega, evaluate the exponential-cosine velocity field, the penetration depth sqrt(2*nu/omega) with exp(-1) amplitude and 1-rad lag, and the wall shear amplitude rho*U*sqrt(nu*omega) leading the plate velocity by 45 degrees. Produces the closed-form velocity profiles, thicknesses and wall-shear histories in SI units for unsteady shear-layer and viscous time-scale checks. Trigger: unsteady-laminar-stokes-layers, stokes-first-problem, oscillating-plate-layer, rayleigh-layer.
bow-shock-standoff
Use when you must estimate the detached bow-shock standoff distance ahead of a blunt nose: compute the standoff ratio Delta over R with the classical Billig-form correlations for a sphere nose and a circular cylinder leading edge at gamma 1.4, convert the ratio to a physical standoff distance for a given nose radius, and report the trend checks that the standoff decreases with Mach and that the cylinder standoff exceeds the sphere standoff at the same Mach. Produces the standoff ratio, the standoff distance and the sanity flags that gate blunt-body nose-radius trades and shock-layer thickness estimates. Trigger: bow shock standoff, billig correlation, stagnation streamline, shock layer thickness, detached shock distance, blunt body nose radius.
compressible-couette-flow
Use when you must compute the exact constant-property solution for compressible Couette flow in a high-Mach plate gap: the linear velocity profile u = Ue y / h, the Crocco energy-integral temperature profile, the insulated moving-plate temperature from the recovery relation r = Pr, the wall shear tau_w = mu Ue / h, the wall heat flux q_w into the stationary plate and the dissipation energy-balance check at a given plate Mach number, Prandtl number and gap Reynolds number. Produces the full gap solution with velocity and temperature profiles. Trigger: compressible-couette-flow, shear-driven-gap-flow, crocco-energy-integral, gap-reynolds-number, plate-gap, linear-velocity-profile, moving-plate, high-mach-plate-gap.
fanno-flow
Use when you must solve the Fanno flow of a steady adiabatic constant-area duct with wall friction: evaluate the fanno-line integral fL*/D that chokes the duct from a Mach number, compute the friction-duct-choking length from the inlet Mach, recover the downstream Mach number for a given friction parameter fL/D on the subsonic or the supersonic branch, find the friction required to choke a duct of given length, and report the total-pressure loss ratio p0/p0* and the static pressure, temperature and density ratios to the sonic state along the duct. Produces the fL*/D values, choke lengths, downstream Mach numbers, friction to choke and the loss ratios that gate duct sizing and gas-dynamics coursework. Trigger: fanno flow, fanno line, friction duct, choking length, adiabatic duct friction, fL*/D.
isentropic-flow-relations
Use when you must convert a Mach number into the isentropic total to static ratios of a compressible flow: the total temperature, pressure and density ratios of a perfect gas at gamma 1.4, rebuild total conditions from a static state and Mach number, recover the Mach number that produces a given area ratio from the area-Mach relation on the subsonic low branch or the supersonic high branch, and compute the choked mass flow a passage passes at its sonic throat from total pressure, total temperature and throat area. Produces the three total to static ratios, both Mach roots for the given area ratio and the choked mass flow in kg/s, the gate numbers for duct and wind tunnel analysis. Trigger: isentropic flow, total to static ratio, mach from area ratio, choked mass flow, sonic throat, wind tunnel contraction, compressible flow, mach number.
rayleigh-flow
Use when you must compute the rayleigh-flow state change of a perfect gas heated or cooled in a constant-area frictionless duct: convert the inlet Mach number into the Rayleigh-line ratios against the sonic state T/T*, p/p*, rho/rho*, T0/T0*, p0/p0*; find the maximum heat addition that thermally chokes the duct from a subsonic or supersonic inlet Mach number, q_max = cp*T1*(1 - M^2)^2/(2*(gamma+1)*M^2); recover the exit Mach number after a given heat addition per unit mass on the inlet branch; and report the entropy rise from the second law. Produces the station ratio set, the choking heat addition, the exit Mach and stagnation pressure ratio, and the entropy rise, in SI units, that gate the heat-addition duct assessment. Trigger: heat addition duct, thermal choking, rayleigh flow, rayleigh line, constant area frictionless duct.
regular-shock-reflection
Use when you must compute the regular reflection of an oblique shock impinging on a wall or symmetry plane: solve the weak-branch incident wave angle at the upstream Mach number and deflection, march the state behind it, solve the reflected shock that turns the flow back parallel to the wall, and assemble the post-reflection state from the two shock ratio products. Produces the incident and reflected wave angles, the intermediate and post-reflection Mach numbers, the pressure, density, temperature and stagnation-pressure ratios, the reflected-shock detachment limit and the regular-versus-Mach verdict. Trigger: regular reflection, reflected shock, wall impingement, symmetry plane, two-shock interaction, Mach reflection, post-reflection state.
shock-tube
Use when you must determine the four-region state of a shock-tube run from the driver-to-driven diaphragm pressure ratio and driver sound-speed ratio: recover the incident-shock Mach number by deterministic bisection of the implicit diaphragm-match equation, then the post-shock pressure, temperature and density ratios with the region-2 absolute state, the contact-surface velocity shared by shocked driven gas and expanded driver gas with the region-2 and region-3 flow Mach numbers, the driver expansion wave ratios with the region-3 absolute state, and the fan head and tail wave speeds. Produces the incident-shock Mach number, the four-region state table and the contact checks that gate shock-tube facility design, driver-gas selection and gas-dynamics coursework. Trigger: shock tube, shock-tube run, diaphragm pressure ratio, contact surface, driver gas, driven gas, incident shock, driver sound-speed ratio, post-shock state, fan head wave, fan tail wave, four-region state table.
added-mass-coefficients-potential-flow
Use when you must determine the added-mass-coefficients-potential-flow virtual mass (apparent mass) of a body accelerating through an inviscid irrotational fluid from the kinetic energy of the irrotational flow it sets up: the 2-D circular cylinder rho pi R^2 and normal flat plate rho pi a^2 per unit span, the 3-D sphere two-thirds rho pi R^3, the elliptic cylinder and the prolate and oblate spheroid coefficients, plus the kinetic-energy and acceleration-reaction relations. Produces the added mass of the requested shape, its ratio to the displaced fluid mass, the fluid kinetic energy at a translation speed, the virtual mass with the body mass, and the acceleration-reaction force for the fluid inertia of unsteady motion. Trigger: added mass coefficients, virtual mass, apparent mass, acceleration reaction force, kinetic energy of irrotational flow, body accelerating in fluid, airship hull added mass, ditching float added mass, spheroid added mass.
sears-function-gust-lift
Use when you must compute the frequency-domain gust response of a rigid thin airfoil to a convected sinusoidal vertical gust: evaluate the complex sears-function S(k) from the Bessel series with the Theodorsen lift-deficiency function, the gust gain and the phase lag of the gust load, and the unsteady gust-load amplitude against the quasi-steady 2*pi*rho*V*b*w_g reference, with the |S| = 1 quasi-steady limit at zero reduced frequency, the monotone gain roll-off, and the reduced frequency where the gust load falls to half the quasi-steady value. Produces the complex sears function, gain and phase tables versus reduced frequency, and the unsteady gust-load amplitudes that gate sinusoidal-gust load estimates and unsteady thin-airfoil coursework. Trigger: sears function, sinusoidal gust, gust transfer function, unsteady gust load, gust reduced frequency sweep.
laminar-far-wake
Use when you must compute the two-dimensional laminar far-wake velocity-defect profile and drag downstream of a thin flat plate or slender body at zero incidence, the Goldstein 1933 similarity wake: evaluate the Gaussian cross-stream velocity-defect profile with the spread parameter U/(4*nu*x), the centerline-defect decay as x^-1/2 and the wake half-width growth as x^1/2 downstream of the trailing edge, integrate the momentum deficit across the wake with the wake-momentum-integral drag identity D = rho*U*integral u1 dy to recover the plate drag, and link the far-wake traverse to the laminar Blasius trailing-edge momentum state with the 0.664 constant. Produces the wake velocity-defect and recovered-velocity profiles, the decay and spreading laws and the wake-survey drag in SI units that anchor laminar wake diagnostics and drag checks. Trigger: laminar-far-wake, far-wake-velocity-defect, wake-momentum-integral, velocity-defect-profile, wake-survey-drag.
mangler-axisymmetric-transform
Use when you must map the steady laminar boundary layer on a slender axisymmetric body of revolution or a sharp cone into an equivalent 2-D flow with the mangler-transformation: evaluate the Mangler transformed running length xi = integral (r0/L)^2 dx and the transformed normal coordinate from the body radius distribution, the cone-surface radius and the equivalent 2-D length for power-law bodies, and the sharp-cone values at equal running length from flat-plate baseline values passed in: skin friction and wall shear times the sqrt-3 laminar cone factor, the 99-percent, displacement and momentum thicknesses divided by sqrt-3, the thinner higher-shear cone layer at the same station. Produces the cone boundary-layer values and the coordinate mapping in SI units that anchor laminar cone-surface and body-of-revolution boundary-layer estimates. Trigger: mangler-transformation, cone-boundary-layer, axisymmetric-body-boundary-layer, laminar-cone-factor, body-of-revolution-bl.
squire-young-profile-drag
Use when you must compute the section profile-drag coefficient of a two-dimensional body or airfoil from the boundary-layer momentum state at its trailing edge: evaluate the squire-young-formula c_d,p = 2*(theta_TE/c)*(U_TE/U_inf)^((H_TE+5)/2) with the documented trailing-edge shape factor about 1.4, and the zero-pressure-gradient reduction to the Blasius flat-plate drag 1.328/sqrt(Re_c) when the trailing-edge velocity equals the freestream. Grows the laminar momentum thickness to the trailing edge on the integral growth relation for the fully laminar chain, then applies the edge-velocity-ratio exponent. Produces the section profile-drag-coefficient, the trailing-edge momentum thickness and the edge-velocity factor that gate airfoil section drag estimates and boundary-layer checks. Trigger: squire young formula, profile drag coefficient, trailing edge momentum thickness, edge velocity ratio, laminar profile drag, momentum integral drag.
stokes-creeping-flow-drag
Use when you must compute the steady low-Reynolds-number viscous drag on a sphere in creeping flow, the Stokes solution for the slow motion of a sphere through a viscous fluid: evaluate the stokes streamfunction and the velocity field about the sphere, the surface pressure and wall-shear distributions with their high-pressure-facing-the-stream signature, the total stokes drag F = 6*pi*mu*a*U split one third pressure drag to two thirds friction drag, the drag coefficient Cd = 24/Re_D at the diameter Reynolds number, the Oseen correction factor 1 + (3/8)*Re_a on the radius-based Reynolds number, and the terminal settling velocity (2/9)*(rho_p - rho_f)*g*a^2/mu of a small dense sphere in still air. Produces the creeping-flow drag, the field values and the settling speed in SI units that anchor low-Reynolds-number body-drag estimates and viscous-flow checks. Trigger: stokes-creeping-flow-drag, creeping-flow, stokes-drag, stokes-streamfunction, oseen-correction, terminal-velocity.
ackeret-linearized-supersonic
Use when you must compute the section coefficients of a thin airfoil at supersonic speed by ackeret linearized supersonic theory: evaluate the ackeret parameter sqrt(M^2 - 1), the surface pressure coefficient Cp = 2*theta/sqrt(M^2 - 1) for a deflection theta, the section lift cl = 4*alpha/sqrt(M^2 - 1), the supersonic lift curve slope, and the wave drag of the flat plate, the thin biconvex circular-arc section and a cambered thin plate from the linearized pressure integral over the surface slopes, with the leading edge moment coefficient cm_le. Produces the ackeret Cp, cl, cd_wave and cm_le values that gate thin supersonic airfoil wave drag estimates, section design cross-checks and gas dynamics coursework. Trigger: ackeret theory, linearized supersonic flow, linear supersonic thin airfoil, biconvex wave drag, supersonic lift curve slope.
hypersonic-piston-theory
Use when you must estimate the surface pressure on a small-perturbation hypersonic surface by Lighthill piston theory: evaluate the piston-theory pressure ratio p/p_inf = (1 + ((gamma - 1)/2) v/a_inf)^(2 gamma/(gamma - 1)) from the piston velocity ratio, apply the linearized limit p/p_inf = 1 + gamma v/a_inf for a small piston velocity, split the compression side from the expansion side of the inclined surface, compute the surface-pressure coefficient Cp = 2/(gamma M^2) (p/p_inf - 1) from the freestream Mach and inclination on either side, and extend the same law to an unsteady surface whose normal motion adds to the geometric piston velocity. Produces the piston-theory surface-pressure ratios, the linearized limits and the per-side and instantaneous pressure coefficients that gate hypersonic panel pressure, stability derivative and oscillating-surface load estimates. Trigger: piston theory, hypersonic piston analogy, small perturbation hypersonic surface pressure, Lighthill.
airfoil-selection
Use when you must select an airfoil section for a wing design: score candidate airfoils by lift-to-drag ratio at the design condition, filter them by minimum thickness, and choose the best qualified section from classic airfoil data. Produces the candidate scoring, the thickness filter verdict, and the selected airfoil identifier that feeds the wing layout. Trigger: airfoil selection, wing design, lift to drag ratio, thickness, naca airfoils, section selection.
cfd-convergence
Use when you must judge whether a computational fluid dynamics run has converged: check that residuals drop below tolerance and stay monotone, confirm the Courant number respects the scheme stability limit, and compare mesh refinement levels for answer stability. Produces the residual verdict, the CFL check, and the mesh convergence flag that decide whether results can be trusted. Trigger: cfd convergence, residual convergence, courant number, mesh refinement, solver stability.
lightning-protection
Use when you must evaluate DO-160 lightning protection for airborne equipment: select the section 22 induced transient susceptibility test level and waveform set, and check the section 23 direct effects pass criteria. Verdict logic classifies whether test results pass with no physical damage, no upset, and no latch-up; level and waveform checks validate inputs before the verdict is issued. Selection and verdict logic only; no standard tables reproduced. Trigger: lightning, DO-160, waveform, test level, transient susceptibility.
airworthiness-liaison
Use when you must manage DO-178C airworthiness and certification liaison for an airborne software item: confirm the certification basis items with evidence, score stage-of-involvement audit readiness against the software level threshold, and track open liaison items to closure before authority audits. Produces the certification-basis coverage account, the SOI readiness verdict, and the open-item action flags that keep the certification plan on schedule. Trigger: airworthiness liaison, certification liaison, soi audit, certification basis, authority communication, audit readiness.
planning
Use when planning DO-178C software certification for airborne systems or equipment: determine the software level or DAL (A-E) from failure-condition severity, draft the PSAC (Plan for Software Aspects of Certification), and scope planning-phase artifacts such as the PSAC, SDP, SVP, SCM, and SQA plans. Covers ARP4754A FDAL/IDAL allocation and ARP4761A severity-to-DAL propagation, including coverage-depth implications per level: A requires MC/DC, B requires decision coverage, C requires statement coverage, D and E require none. Trigger: DO-178C planning, PSAC, software level determination, DAL assignment, development assurance, certification planning, ARP4754A, ARP4761A, airborne software certification.
verification
Use when you must verify DO-178C airborne software against its requirements: review software architecture, design, and code, run requirements-based tests, and analyze structural coverage at the depth the software level demands: A requires MC/DC, B decision coverage, C statement coverage, D and E require none. Determine whether verification must be independent, which applies at levels A and B, and produce the verification results, coverage analysis, and review records the software verification process must deliver. Trigger: DO-178C verification, MC/DC coverage, decision coverage, statement coverage, structural coverage analysis, requirements-based testing, independent verification.
requirements-capture
Use when you must capture and review DO-254 hardware requirements for a complex airborne electronic hardware item: check each requirement for vague terms, missing identifiers, and missing trace links, classify derived requirements from allocated ones, and score capture readiness before the requirements review. Produces the requirement issue list, the derived-versus-allocated classification, and the readiness verdict the design phase consumes. Trigger: hardware requirements, requirements capture, derived requirements, traceability, do-254, requirement characteristics.
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