# JASC 4960: APU Controls

- Type: JASC system/component code (FAA)
- ATA chapter: 49 Airborne Auxiliary Power
- Title in the code table: APU CONTROLS
- Service difficulty reports: 383
- FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=44
- Page: https://openairdocs.org/jasc/4960

## What it covers

The system components which electrically and manually control operation of the APU engine. Typical parts are relay, control box, etc.

## Service difficulty reports (383, newest 50)

- [SDR ABXA20261006459](https://openairdocs.org/sdr/ABXA20261006459), Oct 6, 2026: Boeing 767360. PNEUMATIC SYSTEM. WEAK. APU PNEUMATIC PRESSURE INSUFFICIENT FOR ENGINE START. CREW RETURNED TO THE GATE (BTB). MTC DEFERRED APU PER MEL 49-11-1A (N487CM)
- [SDR I5PA2026091468810](https://openairdocs.org/sdr/I5PA2026091468810), Sep 14, 2026: Boeing 757230. ECU. INOPERATIVE. ETOPS SIGNIFICANT REPORT - APU FAILED TO START. REPLACED APU ECU PER AMM (N688SL)
- [SDR I5PA2025101268801](https://openairdocs.org/sdr/I5PA2025101268801), Oct 13, 2025: Boeing 757230. ECU. FAULTY. FLT: MGE820, APU FAULT, QRH PERFORMED AND RESTART OK. R & R APU ECU IAW AMM, OPS CHECK NORMAL. NO FAULTS ON ECU. (N688SL)
- [SDR SWAA2025080196261](https://openairdocs.org/sdr/SWAA2025080196261), Jul 28, 2025: Boeing 7378. SENSOR. FAULTED. APU OVERSPEED FAULT CODE 49-31014. OK TO CONT PER MEL 49-11-01. R & R APU SPEED SENSOR REF AMM 49-61-21. (N8706W)
- [SDR ABXA202506065119](https://openairdocs.org/sdr/ABXA202506065119), Jun 5, 2025: Boeing 767328. CONTROL UNIT. MALFUNCTIONED. DURING TAXI OUT ALL THREE A/C TEMP CONTROLLERS INDICATED INOP, A/C RETURNED TO THE GATE (BTB) AND MTX GROUNDED A/C . AFT (N1499A)
- [SDR HEEA202505270001](https://openairdocs.org/sdr/HEEA202505270001), May 25, 2025: Skrsky S92A. SENSOR. INOPERATIVE. APU FAIL CAUTION LIGHT ILLUMINATED DURING BEFORE LANDING CHECKS. (N929PH)
- [SDR I5PA2025050588801](https://openairdocs.org/sdr/I5PA2025050588801), May 5, 2025: Boeing 757230. ECU. FAULTY. MX INSP. ESI - APU PNEUMATIC FUNCTON INOP. R & R APU ECU PER AMM. (N888LT)
- [SDR DALA2023111509426](https://openairdocs.org/sdr/DALA2023111509426), Nov 14, 2023: Airbus A330323. UNKNOWN. UNKNOWN. SHIP 3317 WHILE AT GATE DURING PREFLIGHT, APU AUTO SHUTDOWN AFTER FAILED TEST. ECAM MSG -APU "FAULT" EMER SHUT DOWN - F/ (N817NW)
- [SDR I5PA2023110888801](https://openairdocs.org/sdr/I5PA2023110888801), Nov 8, 2023: Boeing 757230. ECU. FAULTY. FLT NO: MGE300. ESI - NO APU BLEED UPON LANDING. R/R APU ECU PER AMM 49-61-05. (N888LT)
- [SDR ASAA2023102345813](https://openairdocs.org/sdr/ASAA2023102345813), Oct 23, 2023: Boeing 7379. UNKNOWN. UNKNOWN. APU FAULT LIGHT ON START. GROUNDED - YES. NO CORRELATED MESSAGE FOUND. NO HISTORY PAST 30 DAYS. CYCLED CB A14 AUX POWER  (N982AK)
- [SDR I5PA2023090688801](https://openairdocs.org/sdr/I5PA2023090688801), Sep 6, 2023: Boeing 757230. ECU. FAULTY. FLT NO: N/A (MX INSP.) ESI - APU PNEUMATIC FUNCTIONS INOP. REPLACED APU ECU PER AMM 49-61-05, OPS TEST OK PER AMM 49-11- (N888LT)
- [SDR ASAA2023090145390](https://openairdocs.org/sdr/ASAA2023090145390), Sep 1, 2023: Boeing 737890. EEC. FAULTY. APU REPORTS SHOW A RAPID RISE IN CT5ATP TEMP AND HAS SURPASSED THE 605 DEGREE THRESHOLD. (#PRI1/ETOPS) CONTACT ETOPS MAI (N594AS)
- [SDR I5PA2023083075703](https://openairdocs.org/sdr/I5PA2023083075703), Aug 30, 2023: Boeing 75729J. ECU. FAULTY. FLT NO: N/A (MX INSP.) ESI - NO APU BLEED PRESSURE. R/R APU POWER CONTROL UNIT PER AMM 49-61-05. (N757QM)
- [SDR I5PA2023082175702](https://openairdocs.org/sdr/I5PA2023082175702), Aug 21, 2023: Boeing 75729J. ECU. FAULTY. FLT NO: MGE301. ESI - APU FAULT. R/R APU POWER CONTROL UNIT PER AMM 49-61-05. (N757QM)
- [SDR I5PA2023052875702](https://openairdocs.org/sdr/I5PA2023052875702), May 28, 2023: Boeing 75729J. ECU. FAULTY. FLT NO: MGE901. ESI - APU FAILED TO START ON GROUND. FOUND FAULTY APU ECU. REPLACED ECU AND PERFORMED APU OPS CHECK PER  (N757QM)
- [SDR ASAA2023051443222](https://openairdocs.org/sdr/ASAA2023051443222), May 14, 2023: Boeing 737890. EEC. FAULTY. APU FAULT LIGHT CHRONIC. GROUNDED - YES. REMOVED AND REPLACED APU ECU, VERIFIED S/N AND SOFTWARE REF B737-800 AMM 49-61- (N513AS)
- [SDR ASAA2023051243233](https://openairdocs.org/sdr/ASAA2023051243233), May 12, 2023: Boeing 7379. UNKNOWN. UNKNOWN. APU FAULT LIGHT ILLUMINATED DURING APU START. GROUNDED - YES. WHILE DOING AN EXISTING FAULT CHECK OF THE APU IN REF TO B (N963AK)
- [SDR ASAA2023050843193](https://openairdocs.org/sdr/ASAA2023050843193), May 8, 2023: Boeing 737890. UNKNOWN. UNKNOWN. APU FAULT LIGHT CAME ON DURING AFTER START FLOW AFTER BOTH ENG'S RUNNING - FAULT LT EXTINGUISHED AFTER ABOUT 5 MINS. GRO (N513AS)
- [SDR ASAA2023050443158](https://openairdocs.org/sdr/ASAA2023050443158), May 4, 2023: Boeing 7379. EEC. FAULTY. DURING PRE-FLIGHT, THE AMBER MAINT LIGHT ON THE OVERHEAD PANEL WAS ILLUMINATED. GROUNDED - YES. STATUS SHOWS APU OIL FAU (N963AK)
- [SDR ASAA2023042342986](https://openairdocs.org/sdr/ASAA2023042342986), Apr 23, 2023: Boeing 737890. UNKNOWN. UNKNOWN. APU FAULT LIGHT. GROUNDED - YES. PERFORMED B737-800 FIM 49-60 TASK 802 FOUND FAULT CODE 49-61116 ECU INTERNAL FAILURE TO (N513AS)
- [SDR ASAA2023030742233](https://openairdocs.org/sdr/ASAA2023030742233), Mar 7, 2023: Boeing 7379. ELECTRONIC UNIT. FAILED. FOLLOWUP TO HISTORY OF APU SHUTDOWN WITH ECU FAILURE MESSAGE. GROUNDED - YES. REMOVED AND REPLACED APU ELEC. CONTROL UNI (N936AK)
- [SDR ASAA2023030542255](https://openairdocs.org/sdr/ASAA2023030542255), Mar 5, 2023: Boeing 7379. UNKNOWN. UNKNOWN. DURING APU START AT GATE, AUTO-SHUTDOWN AND APU FAULT LIGHT ILLUMINATED. EXTINGUISHED AFTER 4 MINUTES. GROUNDED - YES. A (N936AK)
- [SDR ASAA2023021441939](https://openairdocs.org/sdr/ASAA2023021441939), Feb 14, 2023: Boeing 7379. UNKNOWN. UNKNOWN. APU FAULT ILLUMINATED DURING START ON FIRST AND SECOND ATTEMPT. GROUNDED - YES. FOUND MAINT MSG 49-61002 & 49-61144 IN F (N928AK)
- [SDR ASAA2023020841882](https://openairdocs.org/sdr/ASAA2023020841882), Feb 8, 2023: Boeing 737990ER. SENSOR. FAULTY. FAULT LIGHT ILLUMINATES ON APU START. GROUNDED - YES. REMOVED & REPLACED INLET TEMP SW REF B737-900 AMM 49-61-31. (N462AS)
- [SDR DALA2023020600905](https://openairdocs.org/sdr/DALA2023020600905), Feb 3, 2023: Boeing 757232. NOT REPORTED. NOT REPORTED. SHIP 6716 - DIV - DISPATCHED WITH RT ENGINE IDG ON MEL. DURING FLIGHT, APU OIL STATUS MESSAGE. APU AUTO SHUTDOWN. DIVERT (N6716C)
- [SDR I5PA2022121175701](https://openairdocs.org/sdr/I5PA2022121175701), Dec 11, 2022: Boeing 75729J. ECU. FAULTY. FLT NO. N/A (MX INSP). ESI - FOUND APU ECU FAULT. REMOVED AND REPLACED ECU. (N757QM)
- [SDR I5PA2022112075703](https://openairdocs.org/sdr/I5PA2022112075703), Nov 20, 2022: Boeing 75729J. SENSOR. FAULTY. FLT. NO. N/A (MX INSP.). ESI - FOUND P2 SENSOR FAULT ON ECU. REMOVED AND REPLACE P2 SENSOR. (N757QM)
- [SDR ASAA2022111940863](https://openairdocs.org/sdr/ASAA2022111940863), Nov 19, 2022: Boeing 7379. ECU. FAULTY. IN 2 APU START ATTEMPTS, AS SOON AS SWITCH IS SELECTED TO START, APU FAULT LIGHT ILLUMINATES. GROUNDED - YES. CHECK FOUN (N953AK)
- [SDR ASAA2022111540824](https://openairdocs.org/sdr/ASAA2022111540824), Nov 15, 2022: Boeing 7379. EEC. FAULTED. FAULT LIGHT DURING APU START ATTEMPT. GROUNDED - YES. PERFORMED APU BITE PROCEDURE IAW B737-9 AMM 49-61-00, NO FAULTS FO (N949AK)
- [SDR ASAA2022102340487](https://openairdocs.org/sdr/ASAA2022102340487), Oct 23, 2022: Boeing 7379. FAULT LIGHT. FALSE ACTIVATION. APU FAULT LT ON APU START. GROUNDED - YES. CHECKED AND FOUND FAULT MESSAGE 49-89002 "ONBOARD MAINTENANCE FUNCTION HAS NO (N949AK)
- [SDR ASAA2022093040134](https://openairdocs.org/sdr/ASAA2022093040134), Sep 30, 2022: Boeing 7379. APU. FAILED. FAULT LIGHT CAME ON TWICE WHEN STARTING APU. GROUNDED - YES. REMOVED AND REPLACED APU ECU REF B737-9 AMM 49-61-12. (N926AK)
- [SDR ASAA2022080939435](https://openairdocs.org/sdr/ASAA2022080939435), Aug 9, 2022: Boeing 737990ER. SENSOR. DIRTY. WHILE PERFORMING ASA T.C.# 78249000, APU CDU HAS MTX MSG 49-61259 SPEED SENSOR 1 SHOWS OPEN CIRCUIT ON EVERY LEG FOR 15+ (N471AS)
- [SDR I5PA2022080268801](https://openairdocs.org/sdr/I5PA2022080268801), Aug 2, 2022: Boeing 757230. ECU. FAULTY. APU DUCT PRESSURE LOW. R/R APU ECU PER AMM 49-61-05. (N688SL)
- [SDR ASAA2022061038605](https://openairdocs.org/sdr/ASAA2022061038605), Jun 10, 2022: Boeing 737990ER. ECU. FAULTY. APU TREND DATA SHOWS CT5ATP TEMP IS AT OR ABOVE THE THRESHOLD 593 DEGREES BUT LESS THAN 605 DEGREES. GROUNDED - YES. REF (N494AS)
- [SDR ASAA2022060538584](https://openairdocs.org/sdr/ASAA2022060538584), Jun 5, 2022: Boeing 7379. ECU. FAILED. APU FAILS TO START - TWO ATEMPTS FAILED. GROUNDED - YES. INTERROGATED APU VIA OMF FOUND FAULT CODE MX MESSAGE 49-61144.  (N920AK)
- [SDR ASAA2022051738346](https://openairdocs.org/sdr/ASAA2022051738346), May 17, 2022: Boeing 737990ER. SENSOR. FAILED. FOLLOWUP TO HISTORY OF APU OVERSPEED LIGHT AND SHUTDOWN. ETOPS SIGNIFICANT SYSTEM TASK AFFECTS APU ON DEMAND IN-FLIGHT S (N494AS)
- [SDR ASAA2022050638245](https://openairdocs.org/sdr/ASAA2022050638245), May 6, 2022: Boeing 7379. APU. WARNING LIGHT. APU FAULT LIGHT ON START. GROUNDED - YES. FOUND FAULT CODES 49-61149 ECU INTERNAL FAILURE AND 49-61002 APU CONTROLLER DU (N933AK)
- [SDR ASAA2022050638213](https://openairdocs.org/sdr/ASAA2022050638213), May 6, 2022: Boeing 737990ER. APU. FAULTED. APU INOP. GROUNDED - YES. PERFORMED BITE REF B737-900 FIME 49-40-803, PERFORMED AS NORMAL OF THE APU, NO DEFECTS NOTED.  (N477AS)
- [SDR IPXA2022042581457](https://openairdocs.org/sdr/IPXA2022042581457), Apr 18, 2022: Boeing 75724APF. STRAP. CORRODED. INSPECTION TYPE:CCORROSION FOUND AT APU INLET DOOR CUTOUT FRAME AT STA 1825-00REPAIRED PER 757-200PF REV 113.00 CHAPTER  (N428UP)
- [SDR ASAA2022022637582](https://openairdocs.org/sdr/ASAA2022022637582), Feb 26, 2022: Boeing 7379. SENSOR. FAULTY. APU AUTO SHUTDOWN AND DISPLAYED "FAULT" LIGHT AFTER TAXI IN. GROUNDED - YES. REMOVED AND REPLACED INLET TEMP SENSOR REF  (N928AK)
- [SDR ASAA2022022437577](https://openairdocs.org/sdr/ASAA2022022437577), Feb 24, 2022: Boeing 7379. UNKNOWN. UNKNOWN. APU FAULT ILLUMINATED A FEW MINUTES AFTER NORMAL START AND APU SHUTDOWN. GROUNDED - YES. INTERROGATED FAULT HISTORY FOUN (N928AK)
- [SDR DALA2022011200242](https://openairdocs.org/sdr/DALA2022011200242), Jan 11, 2022: Boeing 757232. NONE. NONE. SHIP 6712 - DIV - TO TPA DUE TO SINGLE ELECTRICAL SOURCE. DEPARTED MCO WITH LT ENGINE IDG ON MEL. AFTER LEVEL OFF, APU S (N6712B)
- [SDR ASAA2022010637100](https://openairdocs.org/sdr/ASAA2022010637100), Jan 6, 2022: Boeing 737990ER. UNKNOWN. UNKNOWN. ON SHUTDOWN APU FAULT LIGHT. GROUNDED - YES. CONFIRMED FAULT CODE 49-61223 STARTED B737-900 FIM 49-60 TASK 812 A - F (4) (N457AS)
- [SDR ASAA2022010437099](https://openairdocs.org/sdr/ASAA2022010437099), Jan 4, 2022: Boeing 737890. UNKNOWN. UNKNOWN. APU FAULT LIGHT ILLUMINATED UPON ENGAGING START SWITCH AFTER LANDING. GROUNDED - YES. REMOVED AND REPLACED INLET TEMPERA (N538AS)
- [SDR AALA202112036883](https://openairdocs.org/sdr/AALA202112036883), Dec 2, 2021: Airbus A319112. CONTROL BOX. FAULTY. AIRCRAFT WAS GROUNDED: LEFT GENERATOR # 1 FAILED IN FLIGHT, APU WOULD NOT START. EMERGENCY DECLARED, FLIGHT DIVERTED TO  (N741UW)
- [SDR ASAA2021111436621](https://openairdocs.org/sdr/ASAA2021111436621), Nov 14, 2021: Boeing 7379. UNKNOWN. UNKNOWN. APU FAULT LIGHT ILLUMINATES WHEN STARTING APU. GROUNDED - YES. FOR MSG 49-89002 REF B737-9 IFIM 49-00-00-810-817 FAULT I (N921AK)
- [SDR UIEA2021091702041](https://openairdocs.org/sdr/UIEA2021091702041), Sep 16, 2021: Boeing 767306. ECU. FAULTY. APU FAULT 2 TIMES ON LANDING.(<P>PERFORMED APU BITE PROCEDURE REF AMM 49-61-05. FOUND MINIFLAG #34. RESET APU ECU AND ST (N1427A)
- [SDR UIEA2021071901591](https://openairdocs.org/sdr/UIEA2021071901591), Jul 17, 2021: Boeing 76731K. WARNING MESSAGE. FALSE ACTIVATION. UPON MX ARRIVAL TO FD, FOUND APU BAT CHG STATUS MSG(<P><SPAN>APU TURNED OFF BY INBOUND CREW. RESTARTED APU + FOLLOWED FA (N1487A)
- [SDR 9JLA2021062434856](https://openairdocs.org/sdr/9JLA2021062434856), Jun 17, 2021: Cessna 560XL. SENSOR. DEFECTIVE. THE FLIGHT CREW REPORTED THAT THE APU AUTO SHUTDOWN WHEN BLEED AIR WAS SELECTED ON. THE MAINTENANCE TEAM DETERMINED THAT (N426JN)
- [SDR I5PA2021050488801](https://openairdocs.org/sdr/I5PA2021050488801), May 4, 2021: Boeing 757230. SENSOR. FAULTED. AMBIENT PRESSURE (P2) SENSOR FAILED (LESS THAN 8PSI ON THE GROUND). REPLACED SAME. OPS CHECK NORMAL. (N888LT)

All 383: https://openairdocs.org/jasc/4960/reports.md

## Other codes in chapter 49

- [JASC 4900](https://openairdocs.org/jasc/4900): Airborne Auxiliary Power Unit (APU) System (1,839 reports)
- [JASC 4910](https://openairdocs.org/jasc/4910): APU Cowling/Containment (953 reports)
- [JASC 4920](https://openairdocs.org/jasc/4920): APU Core Engine (2,429 reports)
- [JASC 4930](https://openairdocs.org/jasc/4930): APU Engine Fuel and Control (1,087 reports)
- [JASC 4940](https://openairdocs.org/jasc/4940): APU Start/Ignition System (1,424 reports)
- [JASC 4950](https://openairdocs.org/jasc/4950): APU Bleed Air System (949 reports)
- [JASC 4970](https://openairdocs.org/jasc/4970): APU Indicating System (272 reports)
- [JASC 4980](https://openairdocs.org/jasc/4980): APU Exhaust System (164 reports)
- [JASC 4990](https://openairdocs.org/jasc/4990): APU Oil System (2,650 reports)
- [JASC 4997](https://openairdocs.org/jasc/4997): APU System Wiring (226 reports)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.