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FA-66271 / Aviation weight and balance / Open access

Derate applied to the whole density altitude once above threshold · case 01

Crossing 3000 ft DA suddenly removes 60 lb of allowable weight.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The excess is the full density altitude instead of the amount above the 3000 ft threshold.

VERIFIED REPAIR

Derate only the density altitude in excess of 3000 ft.

Unsuccessful approach: Using the absolute difference also derates fields below the threshold.

Case contract

Input {'elev_ft','altimeter' inHg,'oat_c','mtow'}. Pressure altitude = elev + (29.92 - altimeter)*1000; ISA temp = 15 - 2 per 1000 ft of PA; DA = PA + 120*(OAT - ISA). Allowed weight = MTOW - 20 lb per 1000 ft (pro rata) of DA above 3000 ft, rounded DOWN to 10 lb. Return [DA rounded, allowed].

Why this case matters

A stipulated density-altitude weight derate: the reduction must use pressure altitude, the ISA temperature at that altitude, and conservative rounding.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    pa = x['elev_ft'] + (29.92 - x['altimeter']) * 1000
    isa = 15 - 2 * pa / 1000
    da = pa + 120 * (x['oat_c'] - isa)
    excess = da if da > 3000 else 0.0
    red = 20 * excess / 1000
    allowed = x['mtow'] - red
    return [round(da), int(allowed // 10) * 10]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['hot high field', {'elev_ft': 5100, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [7876, 2450]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.400000000000002, 'oat_c': 25, 'mtow': 2400}, [3705, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -9, 'mtow': 3100}, [5180, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 36, 'mtow': 2550}, [1925, 2550]], ['sampled case 1', {'elev_ft': 4630, 'altimeter': 30.0, 'oat_c': 25, 'mtow': 3600}, [6842, 3520]], ['sampled case 2', {'elev_ft': 8210, 'altimeter': 29.1, 'oat_c': 43, 'mtow': 2550}, [14557, 2310]], ['sampled case 3', {'elev_ft': 4490, 'altimeter': 29.18, 'oat_c': 29, 'mtow': 2550}, [8165, 2440]]], [['hot high field', {'elev_ft': 5200, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8000, 2450]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.380000000000003, 'oat_c': 25, 'mtow': 2400}, [3730, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -8, 'mtow': 3100}, [5300, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 37, 'mtow': 2550}, [2045, 2550]], ['sampled case 1', {'elev_ft': 2900, 'altimeter': 29.44, 'oat_c': 26, 'mtow': 2300}, [5511, 2240]], ['sampled case 2', {'elev_ft': 2480, 'altimeter': 29.04, 'oat_c': -9, 'mtow': 3100}, [1286, 3100]], ['sampled case 3', {'elev_ft': 1880, 'altimeter': 29.23, 'oat_c': 38, 'mtow': 2550}, [5947, 2490]]], [['hot high field', {'elev_ft': 5300, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8124, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.360000000000003, 'oat_c': 25, 'mtow': 2400}, [3754, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -7, 'mtow': 3100}, [5420, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 38, 'mtow': 2550}, [2165, 2550]], ['sampled case 1', {'elev_ft': 5530, 'altimeter': 30.57, 'oat_c': 16, 'mtow': 2550}, [6171, 2480]], ['sampled case 2', {'elev_ft': 8640, 'altimeter': 29.52, 'oat_c': -7, 'mtow': 2550}, [8570, 2430]], ['sampled case 3', {'elev_ft': 8250, 'altimeter': 29.93, 'oat_c': 35, 'mtow': 2300}, [12618, 2100]]], [['hot high field', {'elev_ft': 5400, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8248, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.340000000000003, 'oat_c': 25, 'mtow': 2400}, [3779, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -6, 'mtow': 3100}, [5540, 3040]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 39, 'mtow': 2550}, [2285, 2550]], ['sampled case 1', {'elev_ft': 8680, 'altimeter': 29.91, 'oat_c': -21, 'mtow': 2550}, [6456, 2480]], ['sampled case 2', {'elev_ft': 5840, 'altimeter': 29.35, 'oat_c': 15, 'mtow': 2300}, [7948, 2200]], ['sampled case 3', {'elev_ft': 200, 'altimeter': 30.56, 'oat_c': 11, 'mtow': 2550}, [-1026, 2550]]], [['hot high field', {'elev_ft': 5500, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8372, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.32, 'oat_c': 25, 'mtow': 2400}, [3804, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -5, 'mtow': 3100}, [5660, 3040]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 40, 'mtow': 2550}, [2405, 2550]], ['sampled case 1', {'elev_ft': 5350, 'altimeter': 29.18, 'oat_c': -19, 'mtow': 2550}, [3472, 2540]], ['sampled case 2', {'elev_ft': 1480, 'altimeter': 30.27, 'oat_c': -13, 'mtow': 3600}, [-1959, 3600]], ['sampled case 3', {'elev_ft': 5150, 'altimeter': 30.11, 'oat_c': 16, 'mtow': 3600}, [6270, 3530]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
hot high field[7876, 2390][7876, 2450]Failed
standard sea level[0, 2550][0, 2550]Passed
low pressure[3705, 2320][3705, 2380]Failed
cold high field[5180, 2990][5180, 3050]Failed
just above threshold[3560, 2470][3560, 2530]Failed
below sea level[1925, 2550][1925, 2550]Passed
sampled case 1[6842, 3460][6842, 3520]Failed
sampled case 2[14557, 2250][14557, 2310]Failed
sampled case 3[8165, 2380][8165, 2440]Failed

SHA-256 / 5a0f0b2c82572bdc2d4f551f08ae81ca2e50aa4edfe9ff9fd0177e922c0bbcaf

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    pa = x['elev_ft'] + (29.92 - x['altimeter']) * 1000
    isa = 15 - 2 * pa / 1000
    da = pa + 120 * (x['oat_c'] - isa)
    excess = abs(da - 3000)
    red = 20 * excess / 1000
    allowed = x['mtow'] - red
    return [round(da), int(allowed // 10) * 10]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['hot high field', {'elev_ft': 5100, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [7876, 2450]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.400000000000002, 'oat_c': 25, 'mtow': 2400}, [3705, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -9, 'mtow': 3100}, [5180, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 36, 'mtow': 2550}, [1925, 2550]], ['sampled case 1', {'elev_ft': 4630, 'altimeter': 30.0, 'oat_c': 25, 'mtow': 3600}, [6842, 3520]], ['sampled case 2', {'elev_ft': 8210, 'altimeter': 29.1, 'oat_c': 43, 'mtow': 2550}, [14557, 2310]], ['sampled case 3', {'elev_ft': 4490, 'altimeter': 29.18, 'oat_c': 29, 'mtow': 2550}, [8165, 2440]]], [['hot high field', {'elev_ft': 5200, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8000, 2450]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.380000000000003, 'oat_c': 25, 'mtow': 2400}, [3730, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -8, 'mtow': 3100}, [5300, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 37, 'mtow': 2550}, [2045, 2550]], ['sampled case 1', {'elev_ft': 2900, 'altimeter': 29.44, 'oat_c': 26, 'mtow': 2300}, [5511, 2240]], ['sampled case 2', {'elev_ft': 2480, 'altimeter': 29.04, 'oat_c': -9, 'mtow': 3100}, [1286, 3100]], ['sampled case 3', {'elev_ft': 1880, 'altimeter': 29.23, 'oat_c': 38, 'mtow': 2550}, [5947, 2490]]], [['hot high field', {'elev_ft': 5300, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8124, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.360000000000003, 'oat_c': 25, 'mtow': 2400}, [3754, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -7, 'mtow': 3100}, [5420, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 38, 'mtow': 2550}, [2165, 2550]], ['sampled case 1', {'elev_ft': 5530, 'altimeter': 30.57, 'oat_c': 16, 'mtow': 2550}, [6171, 2480]], ['sampled case 2', {'elev_ft': 8640, 'altimeter': 29.52, 'oat_c': -7, 'mtow': 2550}, [8570, 2430]], ['sampled case 3', {'elev_ft': 8250, 'altimeter': 29.93, 'oat_c': 35, 'mtow': 2300}, [12618, 2100]]], [['hot high field', {'elev_ft': 5400, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8248, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.340000000000003, 'oat_c': 25, 'mtow': 2400}, [3779, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -6, 'mtow': 3100}, [5540, 3040]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 39, 'mtow': 2550}, [2285, 2550]], ['sampled case 1', {'elev_ft': 8680, 'altimeter': 29.91, 'oat_c': -21, 'mtow': 2550}, [6456, 2480]], ['sampled case 2', {'elev_ft': 5840, 'altimeter': 29.35, 'oat_c': 15, 'mtow': 2300}, [7948, 2200]], ['sampled case 3', {'elev_ft': 200, 'altimeter': 30.56, 'oat_c': 11, 'mtow': 2550}, [-1026, 2550]]], [['hot high field', {'elev_ft': 5500, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8372, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.32, 'oat_c': 25, 'mtow': 2400}, [3804, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -5, 'mtow': 3100}, [5660, 3040]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 40, 'mtow': 2550}, [2405, 2550]], ['sampled case 1', {'elev_ft': 5350, 'altimeter': 29.18, 'oat_c': -19, 'mtow': 2550}, [3472, 2540]], ['sampled case 2', {'elev_ft': 1480, 'altimeter': 30.27, 'oat_c': -13, 'mtow': 3600}, [-1959, 3600]], ['sampled case 3', {'elev_ft': 5150, 'altimeter': 30.11, 'oat_c': 16, 'mtow': 3600}, [6270, 3530]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
hot high field[7876, 2450][7876, 2450]Passed
standard sea level[0, 2490][0, 2550]Failed
low pressure[3705, 2380][3705, 2380]Passed
cold high field[5180, 3050][5180, 3050]Passed
just above threshold[3560, 2530][3560, 2530]Passed
below sea level[1925, 2520][1925, 2550]Failed
sampled case 1[6842, 3520][6842, 3520]Passed
sampled case 2[14557, 2310][14557, 2310]Passed
sampled case 3[8165, 2440][8165, 2440]Passed

SHA-256 / c99a42c6812b6152af4c58a91d325aa1e4403f2b50298b26f2d1ab826a03b444

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    pa = x['elev_ft'] + (29.92 - x['altimeter']) * 1000
    isa = 15 - 2 * pa / 1000
    da = pa + 120 * (x['oat_c'] - isa)
    excess = max(0.0, da - 3000)
    red = 20 * excess / 1000
    allowed = x['mtow'] - red
    return [round(da), int(allowed // 10) * 10]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['hot high field', {'elev_ft': 5100, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [7876, 2450]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.400000000000002, 'oat_c': 25, 'mtow': 2400}, [3705, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -9, 'mtow': 3100}, [5180, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 36, 'mtow': 2550}, [1925, 2550]], ['sampled case 1', {'elev_ft': 4630, 'altimeter': 30.0, 'oat_c': 25, 'mtow': 3600}, [6842, 3520]], ['sampled case 2', {'elev_ft': 8210, 'altimeter': 29.1, 'oat_c': 43, 'mtow': 2550}, [14557, 2310]], ['sampled case 3', {'elev_ft': 4490, 'altimeter': 29.18, 'oat_c': 29, 'mtow': 2550}, [8165, 2440]]], [['hot high field', {'elev_ft': 5200, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8000, 2450]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.380000000000003, 'oat_c': 25, 'mtow': 2400}, [3730, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -8, 'mtow': 3100}, [5300, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 37, 'mtow': 2550}, [2045, 2550]], ['sampled case 1', {'elev_ft': 2900, 'altimeter': 29.44, 'oat_c': 26, 'mtow': 2300}, [5511, 2240]], ['sampled case 2', {'elev_ft': 2480, 'altimeter': 29.04, 'oat_c': -9, 'mtow': 3100}, [1286, 3100]], ['sampled case 3', {'elev_ft': 1880, 'altimeter': 29.23, 'oat_c': 38, 'mtow': 2550}, [5947, 2490]]], [['hot high field', {'elev_ft': 5300, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8124, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.360000000000003, 'oat_c': 25, 'mtow': 2400}, [3754, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -7, 'mtow': 3100}, [5420, 3050]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 38, 'mtow': 2550}, [2165, 2550]], ['sampled case 1', {'elev_ft': 5530, 'altimeter': 30.57, 'oat_c': 16, 'mtow': 2550}, [6171, 2480]], ['sampled case 2', {'elev_ft': 8640, 'altimeter': 29.52, 'oat_c': -7, 'mtow': 2550}, [8570, 2430]], ['sampled case 3', {'elev_ft': 8250, 'altimeter': 29.93, 'oat_c': 35, 'mtow': 2300}, [12618, 2100]]], [['hot high field', {'elev_ft': 5400, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8248, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.340000000000003, 'oat_c': 25, 'mtow': 2400}, [3779, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -6, 'mtow': 3100}, [5540, 3040]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 39, 'mtow': 2550}, [2285, 2550]], ['sampled case 1', {'elev_ft': 8680, 'altimeter': 29.91, 'oat_c': -21, 'mtow': 2550}, [6456, 2480]], ['sampled case 2', {'elev_ft': 5840, 'altimeter': 29.35, 'oat_c': 15, 'mtow': 2300}, [7948, 2200]], ['sampled case 3', {'elev_ft': 200, 'altimeter': 30.56, 'oat_c': 11, 'mtow': 2550}, [-1026, 2550]]], [['hot high field', {'elev_ft': 5500, 'altimeter': 30.12, 'oat_c': 30, 'mtow': 2550}, [8372, 2440]], ['standard sea level', {'elev_ft': 0, 'altimeter': 29.92, 'oat_c': 15, 'mtow': 2550}, [0, 2550]], ['low pressure', {'elev_ft': 1500, 'altimeter': 29.32, 'oat_c': 25, 'mtow': 2400}, [3804, 2380]], ['cold high field', {'elev_ft': 6500, 'altimeter': 29.92, 'oat_c': -5, 'mtow': 3100}, [5660, 3040]], ['just above threshold', {'elev_ft': 2000, 'altimeter': 29.92, 'oat_c': 24, 'mtow': 2550}, [3560, 2530]], ['below sea level', {'elev_ft': -200, 'altimeter': 30.2, 'oat_c': 40, 'mtow': 2550}, [2405, 2550]], ['sampled case 1', {'elev_ft': 5350, 'altimeter': 29.18, 'oat_c': -19, 'mtow': 2550}, [3472, 2540]], ['sampled case 2', {'elev_ft': 1480, 'altimeter': 30.27, 'oat_c': -13, 'mtow': 3600}, [-1959, 3600]], ['sampled case 3', {'elev_ft': 5150, 'altimeter': 30.11, 'oat_c': 16, 'mtow': 3600}, [6270, 3530]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
hot high field[7876, 2450][7876, 2450]Passed
standard sea level[0, 2550][0, 2550]Passed
low pressure[3705, 2380][3705, 2380]Passed
cold high field[5180, 3050][5180, 3050]Passed
just above threshold[3560, 2530][3560, 2530]Passed
below sea level[1925, 2550][1925, 2550]Passed
sampled case 1[6842, 3520][6842, 3520]Passed
sampled case 2[14557, 2310][14557, 2310]Passed
sampled case 3[8165, 2440][8165, 2440]Passed

SHA-256 / e4a92c10a5218a52e2f0f427327d7ad0ab59af2bc2f99f735ab4cb8c3a33ef35

Verification & scope

A deterministic toy loading model with stipulated constants; it is not an approved aircraft flight manual procedure and makes no claim of regulatory conformance. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:47:41.751556+00:00.

Case digest / c6c6a81ad99e2ed1186f78ce787dea18df77fdd529dee32316444c684618e176