{"abstract":"Low-pressure days compute a lower pressure altitude and more allowable weight.","category":"Aviation weight and balance","checks":9,"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].","contract_signature":"x","evaluation_group":"w2-aviation-weight-balance-density-altitude-weight","failed_approach":"Scaling by 100 ft per inch keeps the sign but understates the correction tenfold.","family":"w2-aviation-weight-balance-density-altitude-weight-altimeter-sign","id":"FA-66261","implementations":{"attempt":{"sha256":"1c92f7f100af21260a4218600f35cfa0979104f00c32c822e5149551ea861d09","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    pa = x['elev_ft'] + (29.92 - x['altimeter']) * 100\n    isa = 15 - 2 * pa / 1000\n    da = pa + 120 * (x['oat_c'] - isa)\n    excess = max(0.0, da - 3000)\n    red = 20 * excess / 1000\n    allowed = x['mtow'] - red\n    return [round(da), int(allowed // 10) * 10]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['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]]]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"0b1ab6b916328b2998d827430bc1194aacf79cbf5fbf7281cb9f692813bf84cf","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    pa = x['elev_ft'] + (x['altimeter'] - 29.92) * 1000\n    isa = 15 - 2 * pa / 1000\n    da = pa + 120 * (x['oat_c'] - isa)\n    excess = max(0.0, da - 3000)\n    red = 20 * excess / 1000\n    allowed = x['mtow'] - red\n    return [round(da), int(allowed // 10) * 10]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['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]]]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-aviation-weight-balance-density-altitude-weight-altimeter-sign","generated_at":"2026-09-29T14:47:41.810115+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A stipulated density-altitude weight derate: the reduction must use pressure altitude, the ISA temperature at that altitude, and conservative rounding.","root_cause":"The pressure altitude adds (altimeter - 29.92)*1000, reversing the correction.","sha256":"22a2eb9526be899f3b9726f540db925ffa796708c15940c125d22bf6e79f5489","title":"Altimeter setting correction applied with the wrong sign · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.315,"exit_code":1,"observations":[{"actual":[8099,2440],"check":"hot high field","expected":[7876,2450],"passed":false},{"actual":[0,2550],"check":"standard sea level","expected":[0,2550],"passed":true},{"actual":[3124,2390],"check":"low pressure","expected":[3705,2380],"passed":false},{"actual":[5180,3050],"check":"cold high field","expected":[5180,3050],"passed":true},{"actual":[3560,2530],"check":"just above threshold","expected":[3560,2530],"passed":true},{"actual":[2237,2550],"check":"below sea level","expected":[1925,2550],"passed":false},{"actual":[6931,3520],"check":"sampled case 1","expected":[6842,3520],"passed":false},{"actual":[13642,2330],"check":"sampled case 2","expected":[14557,2310],"passed":false},{"actual":[7339,2460],"check":"sampled case 3","expected":[8165,2440],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"hot high field\", \"actual\": [8099, 2440], \"expected\": [7876, 2450], \"passed\": false}, {\"check\": \"standard sea level\", \"actual\": [0, 2550], \"expected\": [0, 2550], \"passed\": true}, {\"check\": \"low pressure\", \"actual\": [3124, 2390], \"expected\": [3705, 2380], \"passed\": false}, {\"check\": \"cold high field\", \"actual\": [5180, 3050], \"expected\": [5180, 3050], \"passed\": true}, {\"check\": \"just above threshold\", \"actual\": [3560, 2530], \"expected\": [3560, 2530], \"passed\": true}, {\"check\": \"below sea level\", \"actual\": [2237, 2550], \"expected\": [1925, 2550], \"passed\": false}, {\"check\": \"sampled case 1\", \"actual\": [6931, 3520], \"expected\": [6842, 3520], \"passed\": false}, {\"check\": \"sampled case 2\", \"actual\": [13642, 2330], \"expected\": [14557, 2310], \"passed\": false}, {\"check\": \"sampled case 3\", \"actual\": [7339, 2460], \"expected\": [8165, 2440], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.871,"exit_code":1,"observations":[{"actual":[8372,2440],"check":"hot high field","expected":[7876,2450],"passed":false},{"actual":[0,2550],"check":"standard sea level","expected":[0,2550],"passed":true},{"actual":[2415,2400],"check":"low pressure","expected":[3705,2380],"passed":false},{"actual":[5180,3050],"check":"cold high field","expected":[5180,3050],"passed":true},{"actual":[3560,2530],"check":"just above threshold","expected":[3560,2530],"passed":true},{"actual":[2619,2550],"check":"below sea level","expected":[1925,2550],"passed":false},{"actual":[7040,3510],"check":"sampled case 1","expected":[6842,3520],"passed":false},{"actual":[12524,2350],"check":"sampled case 2","expected":[14557,2310],"passed":false},{"actual":[6330,2480],"check":"sampled case 3","expected":[8165,2440],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"hot high field\", \"actual\": [8372, 2440], \"expected\": [7876, 2450], \"passed\": false}, {\"check\": \"standard sea level\", \"actual\": [0, 2550], \"expected\": [0, 2550], \"passed\": true}, {\"check\": \"low pressure\", \"actual\": [2415, 2400], \"expected\": [3705, 2380], \"passed\": false}, {\"check\": \"cold high field\", \"actual\": [5180, 3050], \"expected\": [5180, 3050], \"passed\": true}, {\"check\": \"just above threshold\", \"actual\": [3560, 2530], \"expected\": [3560, 2530], \"passed\": true}, {\"check\": \"below sea level\", \"actual\": [2619, 2550], \"expected\": [1925, 2550], \"passed\": false}, {\"check\": \"sampled case 1\", \"actual\": [7040, 3510], \"expected\": [6842, 3520], \"passed\": false}, {\"check\": \"sampled case 2\", \"actual\": [12524, 2350], \"expected\": [14557, 2310], \"passed\": false}, {\"check\": \"sampled case 3\", \"actual\": [6330, 2480], \"expected\": [8165, 2440], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}