Thanks Nick; at least that gives an idea of about how many times is considered to be OK to use up to 5 min of 'Takeoff' power before starting to cut into engine life more than is ideal .
I guess the sad fact is that unless a limit is written specifically, rather than as something that can be argued about, it will be pushed to the letter rather than the spirit of it by those who choose to do so.
Given that use of the 5 minute limit more than about 2.5 times per hour will cause the engine to deteriorate more rapidly than is expected in TBO planning, I guess it follows that a machine that's been subjected to much more than about 12 - 15 minutes per hour in the T/O range for numerous hours is looking statistically worse for likelihood of an engine failure than one that's been 'babied', as some have been terming it; looking for power trends etc to catch it before it fails in that case seems a bit hopeful, to say the least.
Blender mentioned the experienced hands who advised against 'babying' aircraft; experience counts for a lot, certainly, but urban myths and dubious practices can also become accepted truth sometimes, until someone says 'hang on, is what we're doing really a good idea?'
I'm all for working to the limits, but it seems to me to go against logic to pretend that lowering the lever momentarily into the green range and going for it again somehow complies with the manufacturer's intent.
Last edited by Arm out the window; 17th June 2005 at 06:12.