look at the Jetprop in Denmark which was written off because it did extend the gear on such a descent.
What happened?
What happened?
https://aviation-safety.net/wikibase/202945
Regarding the gear the red fluid becomes rock solid at very low temperatures. Then when you operate the gear bad things happen to the hydraulics. I operated the gear twice at low temperatures. Once it did not want to lock fully down and second time the hydraulic pump cb did pop and fluid did leak on an actuator afterwards. Just leave the gear in and let it heat up a bit in warmer air. Only then extend it and all is fine.
So Piper have an approved AFM that calls for gear down in case of emergency descent, and following the procedure damages the gear and creates another serious problem? The only way to know this is to coincidentally read about it in an online forum? Sometimes I wonder. . .
Snoopy wrote:
The only way to know this is to coincidentally read about it in an online forum? Sometimes I wonder. . .
I love the PA46 but the POH is rather low quality. Probably written by the lawyers instead of the engineers. But Piper must have been aware of the landing gear issues at low temperatures. The manual contains a remark that the gravity emergency gear extension can be very slow at low temperatures.
Also the PA46 was initially designed for FL250 and as we can read above the piston engine is not very happy up there so the nomal cruise is more like FL200. But the Jetprop took the airframe up to FL270 and it performs so well up there this is the normal cruise altitude for the plane at much lower temperature on a regular basis.
But then for the Meridian they did certify it to FL300 without doing anything about the gear ;-)
Surely there must be a suitable hydraulic fluid? How do airliners solve this?
Also, statistically, FL250 is just the same as FL270. I have seen -39C on the TB20 
What climb/decend profile do you use to get to FL180?
I climb on IAS/FLC mode at 125KIAS, at 35” 2500RPM, fuel flow to keep CHTs below 370 and TIT below 1450, which usually means 33-35USG; that gives me about 650fpm average up to FL180.
Descent is also on IAS mode at 165KIAS (I know most people prefer VS but the PA46 is quite slippery, descending on IAS keeps me on the green arc); power is 26” 2400RPM 14USG (LOP), giving 800-1000FPM (which in cabin terms is about 300FPM).
Re: oxygen; with its 25K feet ceiling the piston PA46 doesn’t HAVE to have emergency oxygen. I’ve removed mine and I have a Mountain High bottle instead.
Peter wrote:
How do airliners solve this?
They are supposed to have this yellow stuff but I was once told it is highly toxic to the personel working on it whereas the normal red fluid 4 is apparently much nicer.
denopa wrote:
Re: oxygen; with its 25K feet ceiling the piston PA46 doesn’t HAVE to have emergency oxygen. I’ve removed mine and I have a Mountain High bottle instead.
Interesting. I thought that’s only for passengers (at least it ins in CAT ops). Need to read up on it.
I’m enjoying this thread. The Piston PA-46 is my ‘realistic’ dream aircraft.
They are supposed to have this yellow stuff but I was once told it is highly toxic to the personel working on it whereas the normal red fluid 4 is apparently much nicer.
You mean Fluid 41? Airbus uses that for the landing gear (just checked).
That’s used in the TB20 also.
Fatal to eat or inhale.
