What this system is
ATA 49 covers the airborne auxiliary power unit and its installation, control, starting, fuel, oil, air and electrical interfaces.
AIRCRAFT SYSTEM LEARNING
ATA 49 — Airborne Auxiliary Power
ATA 49 covers the airborne auxiliary power unit and its installation, control, starting, fuel, oil, air and electrical interfaces.
LEARNStart with system fundamentalsUse guided learning paths and beginner-friendly explanations.
SOLVEReview troubleshooting casesFind reported symptoms, findings, causes and verified outcomes.
ASKAsk a technical questionUse the community when indexed knowledge does not answer the problem.
UNDERSTANDLook up technical termsMove from unfamiliar terminology into connected learning.
ATA 49
Airborne Auxiliary Power
APU operation, control, fuel, starting and indication.
78%Developing profileNeeds refresh
START LEARNINGStart with the system purpose and major component groups, then use the linked glossary, resources and videos before moving into aircraft-specific detail.
TROUBLESHOOT THIS SYSTEMDefine the reported symptom, confirm aircraft and configuration applicability, then follow current approved fault-isolation and maintenance data.
Why it exists
Provide auxiliary electrical and pneumatic power, commonly for ground operation and sometimes for selected flight conditions.
What belongs here
- APU engine and gearbox
- Air inlet and exhaust
- Starting system
- Fuel and control system
- Oil system
- Bleed-air load control
- Generator
- Fire detection and extinguishing
- Electronic control unit
What users may see
APU speed, exhaust-gas temperature, oil status, generator load, bleed status, start sequence, fire warning and fault messages may be displayed.
What technicians commonly evaluate
Start sequence, inlet and exhaust condition, oil and fuel leaks, hot-section condition, generator and bleed loading, fire protection, control-unit faults and cooldown requirements are common concerns.
AIRCRAFT APPLICABILITY
General ATA knowledge
General ATA knowledge is separated from aircraft-family and exact-variant information.
Choose an aircraft family to narrow resources, cases, questions and indexed applicability.
Choose aircraftCONNECTED KNOWLEDGE
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Content is filtered by the selected ATA chapter and, where indexed, the aircraft and exact variant.
SOURCE & REVIEW BOUNDARY
Use the right information for the right decision.
TechOpsBase supports learning and technical discovery. Current approved maintenance data, engineering instructions and company procedures control real aircraft work.
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