Airworthiness Directive 97-24910
one-timeAirworthiness Directives; AlliedSignal Inc. TSCP700-4B and -5 Auxiliary Power Units
What this AD requires
This amendment supersedes an existing airworthiness directive (AD), applicable to AlliedSignal Inc. (formerly AiResearch and Garrett) TSCP700-4B and -5 Series Auxiliary Power Units (APUs), that currently requires restretching the first stage low pressure compressor (LPC) tie rods, or replacing affected disks at or before 8,000 cycles since new (CSN). This amendment requires removing from service affected disks, replacing them with serviceable parts, and establishing a life limit of 8,000 CSN for affected disks. This amendment is prompted by a report of a first stage LPC disk rim separation due to low cycle fatigue on an APU that had its tie rods restretched in accordance with the current AD. The actions specified by this AD are intended to prevent first stage LPC disk rim separation due to low cycle fatigue, which could result in an uncontained APU failure and damage to the aircraft.
Which aircraft AD 97-24910 applies to
Auxiliary power unit (APU); applies only to units with first stage low pressure compressor (LPC) disk P/N 3606429-1 installed.
Whether AD 97-24910 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
Supersession
Supersedes AD 88-24-07.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.