areobat,
Look at this link:
http://www.hamiltonsundstrand.com/St...eet%202011.pdf
Acc. this the APU may be started and operated up to 43100 feet.
You suggest that the use of APU should be prohibited until the case has been investigated - sounds reasonable.
I flew the BOEING 767 for many years and on this type a serviceable APU was required for flying ETOPS - I do not know the requirements for the BOEING 787, but I assume that the rules are similar. If so, a ban on APU operation airborne would severely restrict the operational capabilities of the BOEING 787.
CharlieDeltaUK,
Check Wikipedia regard ETOPS - they have a good explanation!
Or instead you can check this FAA paper for a VERY comprehensive explanation:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/2e0f31985abd83ef8625746b0057fd06/$FILE/AC%20120-42B.pdf
brgds