Ted
The pilot formerly known as Twin Engine Ted
- Joined
- Oct 9, 2007
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iFlyNothing
I posted this on the Twin Cessna forum, but I thought this would be a good lesson for pilots here.
On the ferry flight when I flew the 414 from BVO to BIE for the annual, I discovered on short final that my airspeed indicator had failed. It did NOT fail by going to zero. It was sticking and thus not decreasing the indicated value as it should have, providing misleading information telling me that I was flying faster than I actually was. For an electronic flight deck, this would be given a hazard level of "Catastrophic." During takeoff and in flight I didn't notice anything that would have me believe the plane was flying abnormally or giving me abnormal airspeed indications, of course I was well within the green arc at that point, taking off faster from a long runway, etc. I also had never flown a 414 before, although I have about 1,000 hours in the 310 and another few hundred hours in Navajos and cabin class turbines.
Because this was a new to me plane (both of type and specific aircraft), I made a 747 sized pattern. I also did this on last weekend's dog run, getting to know the plane more and keeping things conservative. Shallow bank angles.
On about 1 mile final, I had 15 degrees of flaps in, indicating around 100 KIAS. The plane just "felt" slow and mushy. I had a long runway (over 5k feet), no need to do a short field landing, so I pushed the nose down, left the flaps alone, added some power, and came in to land. When I parked and shut off the engines, the airspeed indicator still showed 90 KIAS.
I have no idea how slow I actually was. The stall warning horn didn't go off, but I'm assuming that I was down closer in the 75-80 KIAS range given how the plane felt on final (which is the bottom of the white arc). I Because I recognized the first indication of a stall (starting to feel mushy) I was able to do an easy recovery. Nose down, add some power. DON'T TOUCH THE FLAPS. I gained that extra few knots to make things more comfortable, did a partial flap landing (which is and should be a non-event). It was even a soft landing.
The plane had been sitting for a long time. The right airspeed indicator was labeled inop, but the left one was not. I'm guessing that it was sticking because it had sat for so long.
That said, we should always be vigilant about these sorts of things. Trust thine instruments, but cross check and verify. If you have a GPS, you could diagnose the above problem by cross checking airspeed and ground speed. Keep your stick and rudder skills up to speed and keep the rust off of them. Last week a Cirrus crashed for what appears to have been the same reason. The pilot was on her 3rd attempt to land the plane, and ended up in what was clearly a stall/spin from the video posted of the crash.
Close to 2 years ago, a 414 crashed that had been sitting when the new owner was flying it (only weeks after purchase):
http://www.ntsb.gov/_layouts/ntsb.a...-7b78-4716-b28a-518cbd095163&pgno=1&pgsize=50
While the NTSB final report hasn't come out yet, the fact that it occurred while maneuvering at the destination airport and was a 3-turn spin would tend to indicate a stick and rudder issue, potentially compounded by a mechanical issue such as what happened to me.
But, fortunately, I'm the one telling you about it, and not the NTSB.
On the ferry flight when I flew the 414 from BVO to BIE for the annual, I discovered on short final that my airspeed indicator had failed. It did NOT fail by going to zero. It was sticking and thus not decreasing the indicated value as it should have, providing misleading information telling me that I was flying faster than I actually was. For an electronic flight deck, this would be given a hazard level of "Catastrophic." During takeoff and in flight I didn't notice anything that would have me believe the plane was flying abnormally or giving me abnormal airspeed indications, of course I was well within the green arc at that point, taking off faster from a long runway, etc. I also had never flown a 414 before, although I have about 1,000 hours in the 310 and another few hundred hours in Navajos and cabin class turbines.
Because this was a new to me plane (both of type and specific aircraft), I made a 747 sized pattern. I also did this on last weekend's dog run, getting to know the plane more and keeping things conservative. Shallow bank angles.
On about 1 mile final, I had 15 degrees of flaps in, indicating around 100 KIAS. The plane just "felt" slow and mushy. I had a long runway (over 5k feet), no need to do a short field landing, so I pushed the nose down, left the flaps alone, added some power, and came in to land. When I parked and shut off the engines, the airspeed indicator still showed 90 KIAS.
I have no idea how slow I actually was. The stall warning horn didn't go off, but I'm assuming that I was down closer in the 75-80 KIAS range given how the plane felt on final (which is the bottom of the white arc). I Because I recognized the first indication of a stall (starting to feel mushy) I was able to do an easy recovery. Nose down, add some power. DON'T TOUCH THE FLAPS. I gained that extra few knots to make things more comfortable, did a partial flap landing (which is and should be a non-event). It was even a soft landing.
The plane had been sitting for a long time. The right airspeed indicator was labeled inop, but the left one was not. I'm guessing that it was sticking because it had sat for so long.
That said, we should always be vigilant about these sorts of things. Trust thine instruments, but cross check and verify. If you have a GPS, you could diagnose the above problem by cross checking airspeed and ground speed. Keep your stick and rudder skills up to speed and keep the rust off of them. Last week a Cirrus crashed for what appears to have been the same reason. The pilot was on her 3rd attempt to land the plane, and ended up in what was clearly a stall/spin from the video posted of the crash.
Close to 2 years ago, a 414 crashed that had been sitting when the new owner was flying it (only weeks after purchase):
http://www.ntsb.gov/_layouts/ntsb.a...-7b78-4716-b28a-518cbd095163&pgno=1&pgsize=50
While the NTSB final report hasn't come out yet, the fact that it occurred while maneuvering at the destination airport and was a 3-turn spin would tend to indicate a stick and rudder issue, potentially compounded by a mechanical issue such as what happened to me.
But, fortunately, I'm the one telling you about it, and not the NTSB.
