PA31 Engine Failure Drill
I check the pumps every flight in the way that has been explained. What the manual doesn’t tell you is what is an acceptable time and what isn’t.... discussed with the engineer and was told that anymore than 11 seconds= dicky pump.....
EFATO and Cowl Flaps
I understand some PA31-310's only have one hydraulic pump
Assymetric Flap
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Hi all
I have some 8000hrs of great flying in the PA31-350 and not once did the old girl give me a scare. There were 5 PA31,s in the fleet and were about the same with build dates from 74 through 82.
I admit that it has been a few years since i flew one but do remember most of the operational requirments of it.
TORUK
The prop governor is controlled by oil pressure and fly weights. If you had a complete loss of oil quantity, very quickly , the prop will feather without you doing anything due to the lack of oil pressure. The only way the prop locks will work to keep the prop fine is if the engine gets below 800 rpm. If that happens then the prop will not feather. I have seen this happen to one of the aircraft after a fuel fire and the Pilot put the aircraft into a dive to put it out after shutting of the fire wall shut off valve, he did not feather the prop. When he pulled out of the dive to gain some height back, he then tried to feather to prop but it was stuck in fine. The only way to get it to feather would be to restart the engine to get it above 800rpm.
The out come of this was that with a shut down engine, and a prop not feathered he could not hold height and the landing on a rough road took out the undercarrage.
717tech
As for the gear and hyd pump check you are correct and i did this on every flight.
There has been a lot of talk about the lack of performance on one engine.
I have had a number of shutdowns over that 8000 hrs and not once have i been not able to hold height on one, on hot days and heavy loads.One of the shutdowns was on climb when a seal and a vac pump let go and pumped all the oil out of the right engine, which started the prop into feather before i started to pull the prop lever. I was able to turn back some 70 nm out and climb to 7000ft as i had to cross 50nm water, and was was able to hold that alt all the way back.
43Inches
Your comments as i see it are correct.
As for assymetric flap, i cant remember having a problem, but the aircraft were well looked after
I have some 8000hrs of great flying in the PA31-350 and not once did the old girl give me a scare. There were 5 PA31,s in the fleet and were about the same with build dates from 74 through 82.
I admit that it has been a few years since i flew one but do remember most of the operational requirments of it.
TORUK
The prop governor is controlled by oil pressure and fly weights. If you had a complete loss of oil quantity, very quickly , the prop will feather without you doing anything due to the lack of oil pressure. The only way the prop locks will work to keep the prop fine is if the engine gets below 800 rpm. If that happens then the prop will not feather. I have seen this happen to one of the aircraft after a fuel fire and the Pilot put the aircraft into a dive to put it out after shutting of the fire wall shut off valve, he did not feather the prop. When he pulled out of the dive to gain some height back, he then tried to feather to prop but it was stuck in fine. The only way to get it to feather would be to restart the engine to get it above 800rpm.
The out come of this was that with a shut down engine, and a prop not feathered he could not hold height and the landing on a rough road took out the undercarrage.
717tech
As for the gear and hyd pump check you are correct and i did this on every flight.
There has been a lot of talk about the lack of performance on one engine.
I have had a number of shutdowns over that 8000 hrs and not once have i been not able to hold height on one, on hot days and heavy loads.One of the shutdowns was on climb when a seal and a vac pump let go and pumped all the oil out of the right engine, which started the prop into feather before i started to pull the prop lever. I was able to turn back some 70 nm out and climb to 7000ft as i had to cross 50nm water, and was was able to hold that alt all the way back.
43Inches
Your comments as i see it are correct.
As for assymetric flap, i cant remember having a problem, but the aircraft were well looked after
Thanks GG for the explanation, thats at least two of us that know about the system
Start the left engine first
Quote:
Start the left engine first
Hey goblin I been agreeing with you way too much lately. Finally something to prove that you are backwards afterall!
Start the left engine first
Hey goblin I been agreeing with you way too much lately. Finally something to prove that you are backwards afterall!
Of course now on the turbines it's always the right engine first
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Oei Pa31
Toruk Macto
Re the loss of oil pressure scenario, you are correct that it should feather, I can speak from experience. The other think I can add from experience is that the single engine performance of the PA-31 (admittedly the Chieftain at about MTOW) is woeful. I also ran out of sky, fortunately with something larger and softer to hit.
Re the loss of oil pressure scenario, you are correct that it should feather, I can speak from experience. The other think I can add from experience is that the single engine performance of the PA-31 (admittedly the Chieftain at about MTOW) is woeful. I also ran out of sky, fortunately with something larger and softer to hit.
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43 inches
Tell me about the cabling and/or pushrods in the PA31 undercarriage. As I remember them there was a hydraulic ram for each wheel.
The handpump for the hydraulic system had a saatandpipe which held enough fluid to lower the gear, and this fluid would still be there after a leak in the main system.
Tell me about the cabling and/or pushrods in the PA31 undercarriage. As I remember them there was a hydraulic ram for each wheel.
The handpump for the hydraulic system had a saatandpipe which held enough fluid to lower the gear, and this fluid would still be there after a leak in the main system.
From memory when the gear was up and the uplocks held the gear the hydraulic pressure released and the gear would be held by the uplocks and not the pressure in combination with the uplocks.
When you hand pump the ram is pressurized to extend but I can't remember what disengages the uplock. There is a standpipe in the system to prevent complete loss of fluid like any system however I can't for the life of me remember about the uplock???
When you hand pump the ram is pressurized to extend but I can't remember what disengages the uplock. There is a standpipe in the system to prevent complete loss of fluid like any system however I can't for the life of me remember about the uplock???
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Information Charles
The shut downs did not give me a scare.
Start the right engine first so you could here the starter was in good order. Then the left as you could hear that starter as well.
The shut downs did not give me a scare.
Start the right engine first so you could here the starter was in good order. Then the left as you could hear that starter as well.
Tell me about the cabling and/or pushrods in the PA31 undercarriage. As I remember them there was a hydraulic ram for each wheel.
The handpump for the hydraulic system had a saatandpipe which held enough fluid to lower the gear, and this fluid would still be there after a leak in the main system.
The handpump for the hydraulic system had a saatandpipe which held enough fluid to lower the gear, and this fluid would still be there after a leak in the main system.
Have seen a few instances of the actuator breaking and releasing fluid then there is nothing to release the uplock (on that leg) and only gravity fall if it does unlock. I suppose its more actuator failure than a straight out fluid loss issue. It would have been better for the system to have an uplock release mechanism independant of the hydrualics and gravity fall.
The down locks were a bit touchy about lubrication and roller freedom. Tested the downlocks by lifting them slightly during pre-flight to ensure freedom.
Last edited by 43Inches; 21st Jun 2010 at 07:39.
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Glekichi
I suppose I should have added " out of the respondents on here" not trying to sound smug but also not wanting to state what whould be the bleeding obvious. And yes (I know grammatically incorrect), I am insinuating that there are dodgy endorsements. I have personally seen a C402 endorsement done in one lap of the Phillip Island circuit and checked a newly endorsed pilot (by somebody else) who told me the PA31 had and electrically actuated undercarriage!
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Delta 7
Mate I would only be guessing, it has been 17 years since I flew one and haven't preflighted one for that long. I still have my endorsing notes though
checked a newly endorsed pilot (by somebody else) who told me the PA31 had and electrically actuated undercarriage!
Maybe newly endorsed pilot should have read the POH!
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On another note, colmill do an STC to remove the inner flipper doors.
This would take some of the electrical switching for the HYD system out of the equation.
From memory after gear retraction when the inner doors are closing and don't close the micro switch fully, the system then gives you a red in transit light and the inner doors drop and are left flapping free.
This STC should stop this happening ??, maybe
And as the inner doors are not there for extension, this should be a more simple system.???
This would take some of the electrical switching for the HYD system out of the equation.
From memory after gear retraction when the inner doors are closing and don't close the micro switch fully, the system then gives you a red in transit light and the inner doors drop and are left flapping free.
This STC should stop this happening ??, maybe
And as the inner doors are not there for extension, this should be a more simple system.???
The answer is Yes and No,
The original protection mechanism is what you have described;
The 1 second delay cut-out only occurs if one flap is against a limit switch (fully retracted or extended) and the other is not.
If both flaps are off the limit switch then full assymetry can posibly occur.
Flaps on these aircraft are controlled by the two way switch, you hold the switch in the direction you want flap to travel and monitor the flap guage for position.
In serial numbers 31-7952001 onwards the system has a number of sensors which monitor both flaps position and cut-out the system if a split of 5 degrees or more occurs (no delay). These aircraft have a user freindly flap handle with detents for each flap stage.
However no matter which system you have the basic rules are the same;
1. Don't extend flap with autopilot engaged (it will mask the roll)
2. Extend flap in small increments at a time, Piper recomend no more than half second application in the old paddle type switch.
3. A further recomendation by piper on old models is use no more than 15 degrees flap if the flap breaker has a popping history as it indicates a flight load issue.
With the PA31 know what serial number you are flying and the difference between them. There are some critical speed and operating changes throughout the range even though they all look the same.
The original protection mechanism is what you have described;
The 1 second delay cut-out only occurs if one flap is against a limit switch (fully retracted or extended) and the other is not.
If both flaps are off the limit switch then full assymetry can posibly occur.
Flaps on these aircraft are controlled by the two way switch, you hold the switch in the direction you want flap to travel and monitor the flap guage for position.
In serial numbers 31-7952001 onwards the system has a number of sensors which monitor both flaps position and cut-out the system if a split of 5 degrees or more occurs (no delay). These aircraft have a user freindly flap handle with detents for each flap stage.
However no matter which system you have the basic rules are the same;
1. Don't extend flap with autopilot engaged (it will mask the roll)
2. Extend flap in small increments at a time, Piper recomend no more than half second application in the old paddle type switch.
3. A further recomendation by piper on old models is use no more than 15 degrees flap if the flap breaker has a popping history as it indicates a flight load issue.
With the PA31 know what serial number you are flying and the difference between them. There are some critical speed and operating changes throughout the range even though they all look the same.
Last edited by 43Inches; 21st Jun 2010 at 12:31.