Baronpilot244
Killick Stoker
So we are cruising at FL210 - and its -35C O.A.T. we are in the clear and do not have the ice vanes extended. This btw is in a King Air C90B.
We note that the oil temps on both engines are climbing toward the red line (99C)
Our engines are PT6A-21s with Raisebeck 4 blade turbofan props.
The ITTs are quite low - around 640 and the torque is set at 1200 pounds per side.
Has anyone seen this before? We believe the oil cooler bypasses were probably either frozen open or the probes were thinking it was colder outside than it actually was - this was also a longer than normal flight for us so we really cold soaked the airplane.
We descended to 15000 and the temps came back to normal.
The other problem we had was our pressurization system started acting goofy - cabin diff went into the red and the pneumatic pressure gauge was pegged off the scale. As we descended the diff gauge kept climbing like a reverse altimeter - but the cabin altimeter remained constant so we were confident we weren't overpressurizing the cabin. We turned off the bleeds to confirm the were operating correctly and found this to be true as the cabin became cold. Also once were below 8000 we selected the cabin dump valve to open and basically landed without incident - no ears popping etc.
A night in a heated hangar sorted these problems and the next day i had a mechanic look at the system. He purged the P3 lines with N2 and it hasn't acted up since.
That is until heading home and the EFIS quit cold on me! Was a little exciting for a while as we were in IMC and the copilot's AH tumbled! Turning off the EFIS and allowing it to rest a few minutes helped, I was able to turn it on again and it came back up only to go down about 15 minutes later. Diverted to IAD and managed to get it ack working for an ILS approach in blowing snow!
Now back in warmer temps it all seems to be working fine - it seems it didn't think much of going North!
Anyone have any similar experiences in the 90? Or the 200/350 for that matter?
Bp244
We note that the oil temps on both engines are climbing toward the red line (99C)
Our engines are PT6A-21s with Raisebeck 4 blade turbofan props.
The ITTs are quite low - around 640 and the torque is set at 1200 pounds per side.
Has anyone seen this before? We believe the oil cooler bypasses were probably either frozen open or the probes were thinking it was colder outside than it actually was - this was also a longer than normal flight for us so we really cold soaked the airplane.
We descended to 15000 and the temps came back to normal.
The other problem we had was our pressurization system started acting goofy - cabin diff went into the red and the pneumatic pressure gauge was pegged off the scale. As we descended the diff gauge kept climbing like a reverse altimeter - but the cabin altimeter remained constant so we were confident we weren't overpressurizing the cabin. We turned off the bleeds to confirm the were operating correctly and found this to be true as the cabin became cold. Also once were below 8000 we selected the cabin dump valve to open and basically landed without incident - no ears popping etc.
A night in a heated hangar sorted these problems and the next day i had a mechanic look at the system. He purged the P3 lines with N2 and it hasn't acted up since.
That is until heading home and the EFIS quit cold on me! Was a little exciting for a while as we were in IMC and the copilot's AH tumbled! Turning off the EFIS and allowing it to rest a few minutes helped, I was able to turn it on again and it came back up only to go down about 15 minutes later. Diverted to IAD and managed to get it ack working for an ILS approach in blowing snow!
Now back in warmer temps it all seems to be working fine - it seems it didn't think much of going North!
Anyone have any similar experiences in the 90? Or the 200/350 for that matter?
Bp244
