TBO, APU

Hope to hear from some-one knowledgeable on this subject. What limits TBO (cycles/hours) of an APU ? The APU that is found in the An-32B (intended for operations from high-altitude airfields) can also be found on other Russian fixed-wing aircraft - yet when it is installed in the AN-32B, APU life is reduced by half. Why is this ? Does starting an APU under high altitude conditions impose a special burden on hot-end parts ?

 

[IRstuff]

In military reliability, the key factors are temperature and vibration. If your aircraft has higher vibration or allows the APU to run hotter, that could also explain the difference.

TTFN

 

We are talking about the TG-16M APU, found in the AN-32B, AN-24, AN-26 etc. When the APU is overhauled as for the AN-32B a'cft, Ov'hl Center determines TBO at half that for other aircraft - and makes up the Log Book accordingly. This is on the basis of maker's instructions - we are advised. Hope there is some-one knowledge-able on the TG-16M APU out there (also knowldge-able in English), who can enlighten us on the TG-16M APU, its Fuel Metering equipment etc (configuration for the AN-32B).