PA31 Engine Failure Drill
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PA31 Engine Failure Drill
This may or may not be related to the tragic accident at Canley Vale but who amongst us, endorsed on PA31, would physically select the gear up as part of the engine failure drill if it is already up?
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I would like to know also if there is someone with a tech back ground. The prop governor is controlled by oil pressure and fly weights I believe. If you had a complete loss of oil quantity, very quickly , would you be able to still feather the prop? If you lose pressure would the prop locks work to keep the prop fine / course.
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Captain
The question is necessarily cryptic because I am trying to gauge the level of systems knowledge amongst those endorsed on the type and because a lack of knowledge of that particular system can be a huge gotcha on final with an engine failed.
Been a while since I flew the PA31 (3 years now) however you should check the hydraulic pumps on each engine every flight. Start the left engine first, once she has started pull the gear selector down. On shutdown you would shut the left engine down first then select gear down again to check the right pump.
If you had a left engine failure and you had not had the opportunity to check the right pump, then it's operation could be questioned and you would be wondering if there was enough residual pressure in the system to lower the gear. If however there was not, there is always a manual gear extension available to you. It could be too late however when you decide to lower it to find out you have no pressure and require a manual extension, particularly if you have left it late in the approach sequence due to the marginal performance that is characteristic of a PA31 on one donk.
The gear doors might also open when you select gear up. This is a huge drag penalty if you can't get them closed even with two engines running.
Are you implying the gear doors could have been open on PGW after the gear was selected up on the engine failure drills and was a contributing factor in the loss of performance?
If you had a left engine failure and you had not had the opportunity to check the right pump, then it's operation could be questioned and you would be wondering if there was enough residual pressure in the system to lower the gear. If however there was not, there is always a manual gear extension available to you. It could be too late however when you decide to lower it to find out you have no pressure and require a manual extension, particularly if you have left it late in the approach sequence due to the marginal performance that is characteristic of a PA31 on one donk.
The gear doors might also open when you select gear up. This is a huge drag penalty if you can't get them closed even with two engines running.
Are you implying the gear doors could have been open on PGW after the gear was selected up on the engine failure drills and was a contributing factor in the loss of performance?
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Flying Spike
There are better, more effective ways if imparting your valuable knowledge than this one.
Your approach comes across as rather wankerish.
If you've got something to share it then do so. Otherwise start a poll.
There are better, more effective ways if imparting your valuable knowledge than this one.
Your approach comes across as rather wankerish.
If you've got something to share it then do so. Otherwise start a poll.
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Ok, I will come out with it now. I don't think it is in the manual, but if you select the gear up (with it already up) if there is sufficient pressure from the surviving pump the handle will just reset from the up to the up neutral position. If the handle doesn't reset or is very slow you know you may not be able to extend the gear with the remaining pump and be faced with a manual extention and will have to plan your descent and approach accordingly. I hope that helps somebody
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With that in mind then, as per your first post
1. How is selecting up in an engine failure drill a "gotcha" in a PA-31 when it is already up?
2. How could it possibly have anything to do with the Canley Vale accident?
1. How is selecting up in an engine failure drill a "gotcha" in a PA-31 when it is already up?
2. How could it possibly have anything to do with the Canley Vale accident?
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Consider this: You are on final, haven't checked the gear will come down with the surviving pump, then when you do select the gear down it just unlocks and dangles. Large amounts of drag, pulling you towards Vmca and not enough time to manually extend the gear. I did say it may or may not be a factor in this accident but if helps prevent an accident I will gladly be called "wankerish" by the likes of you. After all I just had to explain that to you.
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Well done on the change of tack.
Imparting knowledge with the use of poorly worded and obscure questioning is generally considered a poor instructional technique.
Is this widely useful for most light twins or is it PA31 specific?
Imparting knowledge with the use of poorly worded and obscure questioning is generally considered a poor instructional technique.
Is this widely useful for most light twins or is it PA31 specific?
is this widely useful for most light twins or is it PA31 specific?
A PA31 has two hydraulic pumps operating a common system powered by each engine. Either is capable of operating the system on their own at a reduced rate. Most light twins have an electrically driven pump.
When you select gear up or down in the PA31 after the cycle is complete the gear handle will spring back to the neutral position. Sometimes it will be very slow if the engine is at idle or the pump is dicky. If you check it and it does not spring back to the neutral position the pump(s) are faulty.
Quite common on takeoff is for the gear doors to not close properly and you will have a red gear position light. Instead of selecting the gear down again and then up, you just need to lift the handle from neutral to up and it should solve the problem then spring back to neutral when the system is pressurized again.
Thinking about this further I don't think the gear doors could open if you selected the gear up in your EFATO drill. It could dissipate pressure in the system for an extension if the operating engines pump was faulty however as I previously mentioned.
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Thanks GG for the explanation, thats at least two of us that know about the system. I was going to expand on it but you beat me to it and did a better job than I would have done.
P.S. I wonder if Waren 9 knows of his namesake in QF? If he did he may well be an expert on "wankerishness"
P.S. I wonder if Waren 9 knows of his namesake in QF? If he did he may well be an expert on "wankerishness"
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Assymetric Flap
I only ever had it happen once and that was on take-off in a Dove. PA31, I am not sure but I am sure it has something to do with with those roller thingies on the flapp runners I used to check underneath every pre-flight.
Piper service letter 959 also explains the mod to fix problems with th 20:1 drive as well. Might be worth a look
http://www.airdisaster.com/reports/ntsb/AAR82-11.pdf
is also a good read
Piper service letter 959 also explains the mod to fix problems with th 20:1 drive as well. Might be worth a look
http://www.airdisaster.com/reports/ntsb/AAR82-11.pdf
is also a good read
Last edited by flying-spike; 20th Jun 2010 at 02:58.
The good 'ole assymetric flap extension in the PA31 
Many I flew had the runners jammed so the flaps could not extend past 30 degrees, you used to be able to get it pretty slow at 40 degrees that's for sure!
I used to count when I selected flap on the Navajos, 1000, 2000, 3000. That would give me 10 degrees on downwind. Count the same again for 20 degrees and let them run down on their own for 30 (or 40) degrees. I used to count to 5 for the cowl flaps too. That would give you a 5 knot reduction in airspeed and was good to slow down if you were a little too quick on your profile (in warm weather) I'd leave them closed until exiting the runway if it were cold.
As much as they are a bucket, I do miss them occasionally but I cry for a Baron and a 404!
Many I flew had the runners jammed so the flaps could not extend past 30 degrees, you used to be able to get it pretty slow at 40 degrees that's for sure!
I used to count when I selected flap on the Navajos, 1000, 2000, 3000. That would give me 10 degrees on downwind. Count the same again for 20 degrees and let them run down on their own for 30 (or 40) degrees. I used to count to 5 for the cowl flaps too. That would give you a 5 knot reduction in airspeed and was good to slow down if you were a little too quick on your profile (in warm weather) I'd leave them closed until exiting the runway if it were cold.
As much as they are a bucket, I do miss them occasionally but I cry for a Baron and a 404!
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Which PA31?
Well I have been waiting for a while and no one has mentioned that there are different PA31's as in I understand some PA31-310's only have one hydraulic pump. Any comments!
groggy
groggy