F27 single engine ceiling??

[m&v]

My son is flying the F27 over the rocks.His Airplane flight Manual is showing it's age and the graph depicting the eng-out ceiling is hard to decipher.Ergo what sort of 'altitude'can the F27 drift down to,at a reasonable weight,and maintain on one??
Many thanks..
M&V:confused:

[john_tullamarine]

... going to depend on Mark, engine, weight, ambients .. a bit more info might help ...

[Loose rivets]

Hi,

I have executed some of the most turbulent approaches imaginable in an F27.... Leeds-B was one of the worst, with a 60kt gust on the stb rear quarter just on touch-down. A somewhat memorable night. It seemed a robust and reliable old aircraft...but. The drift-down needs careful thought, the graphs being only the first consideration. When flying in mountainous terrain in rough air, obviously energy is soaked up and the graphs are meaningless. I would council a very cautious routes, and don't be bullied into straight-lining it, just because an ancient graph says it's OK

[fruitbatflyer]

OK, here are some ballpark figures derived from old test notes, taken in the days when I did some pre delivery testing and annual C of A tests etc on these wonderful machines.
They fall a bit short of Flight Manual figures, but then the airframes were not new and I was only self-taught as a test pilot.
Hence probably realistic for Joe Average flying an old dog of an airframe.

SERIES 100 with 514 engines at 18,000kg would maintain 9000 ft with pressurization OFF (spill valves open) at ISA, no ice, one engine feathered.
At ISA+25, same weight, same engines, it would only maintain 4500ft with pressurization off.

The later series such as 200 with 528 engines were a little better but then we got up to the 500 series with 536 engines which could operate up to about 21,000kg but at that weight they were just as bad as the 100 series, especially at ISA + 25. The only difference was that you didn't have to dump the pressurization if you lost an engine, but at those altitudes it was a bit academic.

I flew all variants in high temps and also in icing conditions in the Iranian winters over terrain around the 17,000ft mark. Any ice, especially on the belly, where it sticks like poo to a blanket, and you quickly got back near stick shaker even at full throttle on BOTH engines! We had to plan our drift downs very carefully.

One would hope that Transport Canada requires such drift down planning when flying over the rocks. In doing so, remember that you have to clear the highest terrain in the drift down path by 2000ft, not 1000ft as is often supposed. The only reason I can think of for this is to allow for unknown headwind, but will stand corrected if anyone has another answer.

[m&v]

Thanks FBF for the info.Needless to say they've gone into the charts/graphs etc and started their 'cruise' at a reasonable level(18/19K),but the question always raised the point -where would they end up.The low alt enroute MEA's need about 11600 at one point,but they can drift down to a 'lower' segment(as you say depending on wind component).TransPort Can do expect the operator will do the proper thing(driftdown/escaperoutes etc)but they don't necessarily demand an flight test....
Thanks again...
Thanks JT i'll try to get the exact type/eng marques etc..
Cheers:confused:

FBF,the 2000 buffer is to account for Temp/Pressure corrections
Transport canada AIP:Min IFR alts 8.5 of rules o' the air..
again many thanks
cheers...:O

[john_tullamarine]

re 2000 vs 1000, I have never seen anything definitive. However there is a simple, and likely rationale.

For the level cruise case data is based on flight test. For a book aircraft and appropriate met conditions, the aircraft could be expected to make published OEI level plus a delta reflecting the certification fudge factor .. ie the operation is somewhat predictable. In the real world, naturally enough, we put in some fat for mum and the kids to account for age and met conditions even if this is only done on a seat of the pants basis to some extent.

For the drift down case, the certification flight test data may well be repeatable for book aircraft and appropriate met conditions but there is a considerable credibility gap in the accuracy of matching the critical obstacle to the physical drift down locus in 3D space. Remember that these rules go back a long way when the pilot might well have only an approximate idea of his real location. Someone, somewhere in the regulatory business had to draw a line in the sand and than line was 2000ft. Keep in mind also that there is a certification fudge factor in the performance so the book figures provide an additional margin for book aircraft and appropriate met conditions.