How long to feather in a Seneca 1?
Thread Starter
Joined: Jun 2000
Aviation Qualifications: ATP+Mil
Posts: 4,698
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From: Australia
How long to feather in a Seneca 1?
During endorsement training in a Seneca 1, it took 6 seconds to feather the right engine, which I believe is a normal time. However, the left engine took 20 seconds to stop in the feather position from the time the pitch lever hit the feather position.
This could be deadly as there is significant drag for this amount of time, which certainly would reduce the already poor rate of climb.
It was also noticed that during the run-up and feather action checked on the suspect engine, the drop in rpm was very slow. The maintenance engineer signed out the feather system as serviceable. I do not agree.
Request info on certification times for feathering in the air. I think it is around six seconds. Are the certification times for feather in the Seneca 1 valid for a range of speeds or is it only valid for feather action at blue line speed?
Also, when the manifold pressure and RPM was set for 65% power (from the tables)in cruise (around 140 knots IAS), as soon as the mixtures were adjusted to give 65% on the fuel flow needles, the aircraft lost 20 knots IAS. When the mixtures were set to full rich the aircraft returned to normal cruise IAS of 140 knots. This was repeated several times as we did not believe our eyes. Altitude was 3500 ft at ISA temp. Any ideas on this would be appreciated.
[ 23 February 2002: Message edited by: Centaurus ]</p>
This could be deadly as there is significant drag for this amount of time, which certainly would reduce the already poor rate of climb.
It was also noticed that during the run-up and feather action checked on the suspect engine, the drop in rpm was very slow. The maintenance engineer signed out the feather system as serviceable. I do not agree.
Request info on certification times for feathering in the air. I think it is around six seconds. Are the certification times for feather in the Seneca 1 valid for a range of speeds or is it only valid for feather action at blue line speed?
Also, when the manifold pressure and RPM was set for 65% power (from the tables)in cruise (around 140 knots IAS), as soon as the mixtures were adjusted to give 65% on the fuel flow needles, the aircraft lost 20 knots IAS. When the mixtures were set to full rich the aircraft returned to normal cruise IAS of 140 knots. This was repeated several times as we did not believe our eyes. Altitude was 3500 ft at ISA temp. Any ideas on this would be appreciated.
[ 23 February 2002: Message edited by: Centaurus ]</p>
Joined: Jul 2001
Posts: 156
Likes: 0
From: England
Sounds like a severley knackered Seneca and I would agree that 20 seconds to feather is dangerous. The Seneca I's I have flown have all feathered in about 6 seconds. Lets face it the Seneca I is dangerous without having a problem like that!
Joined: May 2001
Posts: 4,729
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From: 75N 16E
If its the same as Seneca II then the feather system is operated by pressurized Nitrogen....could be low on pressure and needs a top up...but it certainly needs a good check. I wouldn't fly that aircraft.......
Joined: Feb 2002
Posts: 42
Likes: 0
From: 5 km from ESGG
A few years ago I flew the Seneca II quite a lot. On one flight I was asked by the maintenance manager to test feather the left prop after a prop change. If my memory serves me right he said the limit was 8 seconds.
