Forced Landing trouble check drill
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Joined: Jun 2000
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From: Australia
Forced Landing trouble check drill
During the forced landing engine failure trouble check, do you agree that part of the trouble check (assuming a mysterious failure) should include operating the primer (Cessnas and Warriors et al) then try a re-start?
I notice that in all manuals that I have read on the subject of practice forced landings without power, there is no mention of using the primer as part of any attempt to re-start in flight.
I notice that in all manuals that I have read on the subject of practice forced landings without power, there is no mention of using the primer as part of any attempt to re-start in flight.
Joined: Dec 1998
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From: Escapee from Ultima Thule
I included it in trouble check drills I taught ever since I saw how an unlocked primer can stop the engine.
It occurred on the ground with a student once but I'm bright enough to extrapolate!
It occurred on the ground with a student once but I'm bright enough to extrapolate!
Joined: Jul 2001
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From: South Yorkshire
Centaurus has asked an odd question, and then gone on to cloud the issue with an even odder comment (IMHO)!
I don't agree that operating the primer as part of your investigation into the cause of the failure is a reasonable thing to do. As Tinstaafl says, operating the primer is likely to lead to the engine STOPPING, not causing it to burst back into life following a mysterious stoppage. If fuel starvation was the cause of the stoppage, I think it highly unlikely to primer could suck any fuel in (where would it suck it from) - and if it did manage to suck in some fuel, so what - the only impact would be to supply a drop of fuel to an engine that has stopped because it has run out. If you operate the primer quickly while the engine is still coughing and spluttering it, will just cough and splutter some more and die about one turn of the crankshaft after it would have died if you had not operated the primer. So no gain there, and if you operate the primer after the engine has died, you just get a primed engine. The action would not, in my opinion assist with the fault diagnosis.
Centaurus' odder comment was that use of the primer help, or indeed be needed to, re-start an engine after it had stopped. I think this very unlikely unless you have spent ages descending and the engine had got cold like wot it is in the morning.
I don't agree that operating the primer as part of your investigation into the cause of the failure is a reasonable thing to do. As Tinstaafl says, operating the primer is likely to lead to the engine STOPPING, not causing it to burst back into life following a mysterious stoppage. If fuel starvation was the cause of the stoppage, I think it highly unlikely to primer could suck any fuel in (where would it suck it from) - and if it did manage to suck in some fuel, so what - the only impact would be to supply a drop of fuel to an engine that has stopped because it has run out. If you operate the primer quickly while the engine is still coughing and spluttering it, will just cough and splutter some more and die about one turn of the crankshaft after it would have died if you had not operated the primer. So no gain there, and if you operate the primer after the engine has died, you just get a primed engine. The action would not, in my opinion assist with the fault diagnosis.
Centaurus' odder comment was that use of the primer help, or indeed be needed to, re-start an engine after it had stopped. I think this very unlikely unless you have spent ages descending and the engine had got cold like wot it is in the morning.
Joined: Dec 1998
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From: Escapee from Ultima Thule
Ensuring that the primer is locked helps with fault diagnosis. If an unlocked primer is the cause of the stoppage then correcting that problem may be all that's needed to restart the engine.
Joined: Oct 2001
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From: Vancouver Island
Im a bit puzzeled about how an unlocked primer can stop an airplane engine in flight.
Can anyone elaborate on what make of engine this phenomenom occurs with and just how this can happen?
..............
The hardest thing about flying is knowing when to say no.
Can anyone elaborate on what make of engine this phenomenom occurs with and just how this can happen?
..............
The hardest thing about flying is knowing when to say no.
Joined: Oct 2001
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From: United Kingdom
Cat Driver.
This can happen to engines in most training aircraft, certainly Lycoming. If the primer is out during flight too much fuel is drawn into the carb causing a 'rich cut', too much fuel and not enough air for proper combustion.
This can happen to engines in most training aircraft, certainly Lycoming. If the primer is out during flight too much fuel is drawn into the carb causing a 'rich cut', too much fuel and not enough air for proper combustion.
Joined: Oct 2001
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From: Vancouver Island
Buster:
O.K.... however I have never experienced such a failure in flight. I have experimented with unlocking the primer to see just what effect it has and it can or will run rough, however with the throttle in the cruise position I have never experienced a complete loss of power.
Don't get me wrong I am not saying it won't happen on some engine, carb. setups, I just never experienced it.
Another observation... with regard to a primer becoming unlocked in cruise flight, that would be a remote possibility, because if it was not properly locked after priming for the engine start it would in all likelyhood unlock either during taxi ( where it can definately stop the engine ) or during the take off climb segment of the flight.
Any further ideas on my comments? Cause I sure as hell do not pretend know everything about airplanes.
................
The hardest thing about flying is knowing when to say no.
O.K.... however I have never experienced such a failure in flight. I have experimented with unlocking the primer to see just what effect it has and it can or will run rough, however with the throttle in the cruise position I have never experienced a complete loss of power.
Don't get me wrong I am not saying it won't happen on some engine, carb. setups, I just never experienced it.
Another observation... with regard to a primer becoming unlocked in cruise flight, that would be a remote possibility, because if it was not properly locked after priming for the engine start it would in all likelyhood unlock either during taxi ( where it can definately stop the engine ) or during the take off climb segment of the flight.
Any further ideas on my comments? Cause I sure as hell do not pretend know everything about airplanes.
................
The hardest thing about flying is knowing when to say no.
Joined: Oct 2001
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From: United Kingdom
Cat Driver
The fact that an unlocked primer can cause rough running is good enough for me to make sure that it is locked when I have an engine failure. It may not be the primer that has caused the problem but the idea of the engine failure cx is to eliminate all the possible causes,or hopefully find the problem. As you say it is only a remote possibility but for all the time it takes its worth checking. Even if it had been locked, the locking pin could have broken!!! ok so that really is a remote possibility but we read strange things in accident reports all the time.
The fact that an unlocked primer can cause rough running is good enough for me to make sure that it is locked when I have an engine failure. It may not be the primer that has caused the problem but the idea of the engine failure cx is to eliminate all the possible causes,or hopefully find the problem. As you say it is only a remote possibility but for all the time it takes its worth checking. Even if it had been locked, the locking pin could have broken!!! ok so that really is a remote possibility but we read strange things in accident reports all the time.
Joined: Nov 2000
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From: St Albans, herts, UK
A quick Google using "primer unlocked accident" found these easily.
<a href="http://www.canard.com/ntsb/LAX/88A050.htm" target="_blank">accident 1</a>
<a href="http://www.canard.com/ntsb/FTW/89A017.htm" target="_blank">accident 2</a>
<a href="http://www.eagletribune.com/news/stories/19991114/LN_005.htm" target="_blank">accident 3</a>
It's enough for me to make sure the primer's locked and stays locked....
<a href="http://www.canard.com/ntsb/LAX/88A050.htm" target="_blank">accident 1</a>
<a href="http://www.canard.com/ntsb/FTW/89A017.htm" target="_blank">accident 2</a>
<a href="http://www.eagletribune.com/news/stories/19991114/LN_005.htm" target="_blank">accident 3</a>
It's enough for me to make sure the primer's locked and stays locked....
Joined: Oct 2001
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From: Vancouver Island
Hey guys:
I was not suggesting that checking the primer was incorrect after an engine failure, I was merely pointing out that a primer is extreemly unlikely to cause a complete loss of power.
Continental 0-200's are generaly primed into the intake above the carb as I recall. Lycomings generally are primed straight into the cyl. heads , it varies on the engine how many cylinders are primed.
So to reiterate, all I was doing was trying to clarify the cause of a complete engine failure in flight. To be more precise when instructing students in forced landing procedures we are normally at a sufficient altitude to complete all nessary checks. The only exception would be an engine failure right after take off, going through a lenghthy check list would be the last thng you would do in that case.
The three accident reports that were posted reinforces the point I was trying to make. Unlocked primers do not result in complete engine failures.
As to my unlocking the primer in flight why should that prove to be problimatic?
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The hardest thing about flying is knowing when to say no.
I was not suggesting that checking the primer was incorrect after an engine failure, I was merely pointing out that a primer is extreemly unlikely to cause a complete loss of power.
Continental 0-200's are generaly primed into the intake above the carb as I recall. Lycomings generally are primed straight into the cyl. heads , it varies on the engine how many cylinders are primed.
So to reiterate, all I was doing was trying to clarify the cause of a complete engine failure in flight. To be more precise when instructing students in forced landing procedures we are normally at a sufficient altitude to complete all nessary checks. The only exception would be an engine failure right after take off, going through a lenghthy check list would be the last thng you would do in that case.
The three accident reports that were posted reinforces the point I was trying to make. Unlocked primers do not result in complete engine failures.
As to my unlocking the primer in flight why should that prove to be problimatic?
..........
The hardest thing about flying is knowing when to say no.
Joined: Dec 1998
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Likes: 6
From: Escapee from Ultima Thule
Because it will change the mixture. Depending on circumstances eg throttle & mixture settings, Density Ht, Carby Ht/presence of intake icing etc it can be enough to give you an engine failure.
As for checking it immediately after take-off, I think we have a difference in terminology/procedures. What I give below are very generalised & often change depending on a/c type.
Vital or immediate actions: Things to be done as soon as an engine failure is recognised
*Carby Ht: ON
*Mixture: RICH
Fuel pump: ON
Fuel: ON or change tanks
Then:
*Pick a place to land & establish a flight path to get to it
*Get a MAYDAY broadcast
*Look after the pax
Troubleshoot checks:
In a nutshell try everything else that might get the engine running.
*Recheck the vital actions (in the initial...erm... 'excitement' it's easy to mis-select something.
*Try each mag. in turn
*Primer: Locked
*Exercise the throttle
*Exercise the mixture
So, in the EFATO primer isn't appropriate BUT in other cases where there is time to troubleshoot then it is.
Hope that clarifies things a bit.
As for checking it immediately after take-off, I think we have a difference in terminology/procedures. What I give below are very generalised & often change depending on a/c type.
Vital or immediate actions: Things to be done as soon as an engine failure is recognised
*Carby Ht: ON
*Mixture: RICH
Fuel pump: ON
Fuel: ON or change tanks
Then:
*Pick a place to land & establish a flight path to get to it
*Get a MAYDAY broadcast
*Look after the pax
Troubleshoot checks:
In a nutshell try everything else that might get the engine running.
*Recheck the vital actions (in the initial...erm... 'excitement' it's easy to mis-select something.
*Try each mag. in turn
*Primer: Locked
*Exercise the throttle
*Exercise the mixture
So, in the EFATO primer isn't appropriate BUT in other cases where there is time to troubleshoot then it is.
Hope that clarifies things a bit.
Joined: Oct 2001
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From: Vancouver Island
Why, oh why, do I get myself into these discussions on the flight instructor forum????
I guess I will never learn.
Tinstaafl..... my last question on my last post was rhetorical, if you would read one of my first posts on this subject you will note that I only commented that I have unlocked the primer in flight to demonstrate to some student somewhere in the dim past that the engine would run excessively rich and lose power, it would not however quit completely.
I will once again confess to being my own worst enemy by even trying to comment on an instructor forum.
From now on I will desperately try to be less opinionated about flight training. <img src="wink.gif" border="0"> <img src="wink.gif" border="0"> <img src="wink.gif" border="0">
.................
The hardest thing about flying is knowing when to say no.
I guess I will never learn.
Tinstaafl..... my last question on my last post was rhetorical, if you would read one of my first posts on this subject you will note that I only commented that I have unlocked the primer in flight to demonstrate to some student somewhere in the dim past that the engine would run excessively rich and lose power, it would not however quit completely.
I will once again confess to being my own worst enemy by even trying to comment on an instructor forum.
From now on I will desperately try to be less opinionated about flight training. <img src="wink.gif" border="0"> <img src="wink.gif" border="0"> <img src="wink.gif" border="0">
.................
The hardest thing about flying is knowing when to say no.
Joined: Dec 1998
Posts: 4,282
Likes: 6
From: Escapee from Ultima Thule
[quote]...I have never experienced such a failure in flight. I have experimented with unlocking the primer to see just what effect it has and it can or will run rough, however with the throttle in the cruise position I have never experienced a complete loss of power.<hr></blockquote>
Later you refer to teaching PFLs.
No mention of you experimenting with a student on board. Only that you did it.
As for problematic: Isn't the unlocked primer(s) mentioned in the accident reports indicative of 'problematic'?
Later you refer to teaching PFLs.
No mention of you experimenting with a student on board. Only that you did it.
As for problematic: Isn't the unlocked primer(s) mentioned in the accident reports indicative of 'problematic'?
Joined: Oct 2001
Posts: 2,517
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From: Vancouver Island
OK Guys:
Lets do this once more.
The three accident reports do not state that an unlocked primer caused the engine to stop. Except for report #2 which suggested that excessive fuel burn led to fuel exhaustion over a period of time not stated. The unlocked primer was noted as maybe a contributing factor to running out of fuel.
Report #3 is pure rubbish, just read the idiotic descriptions of the probable cause and check who wrote it.
Several 0f you claim an unlocked primer will cause a complete stoppage of the engine.
Please tell me when this has ever happened.
For what it is worth the last time I instructed at the PPL level was some time ago, however it seems to me that a lot of flying instructors make the most basic things into bigger issues than they really are.
Anyhow guys show me proof that an unlocked primer will cause a complete stoppage of an engine on these basic trainers.
................
Lets do this once more.
The three accident reports do not state that an unlocked primer caused the engine to stop. Except for report #2 which suggested that excessive fuel burn led to fuel exhaustion over a period of time not stated. The unlocked primer was noted as maybe a contributing factor to running out of fuel.
Report #3 is pure rubbish, just read the idiotic descriptions of the probable cause and check who wrote it.
Several 0f you claim an unlocked primer will cause a complete stoppage of the engine.
Please tell me when this has ever happened.
For what it is worth the last time I instructed at the PPL level was some time ago, however it seems to me that a lot of flying instructors make the most basic things into bigger issues than they really are.
Anyhow guys show me proof that an unlocked primer will cause a complete stoppage of an engine on these basic trainers.
................
Joined: Oct 2001
Posts: 2,517
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From: Vancouver Island
Tinstaafl:
From your profile it is difficult to determine if you are a licensed, working flight instructor.
In any event I had assumed you and I are discussing the an unlocked primer causing a complete engine failure in flight in the air.
Then this morning I went back and read all the posts on this subject and I note your opinion is based on that you can extrapolate.
Flying instructors have a duty to teach and pass on information based on facts, not their ability to "extrapolate" in the discussion we are having regarding unlocked primers the facts are that a light aircraft engine such as for instance the Cessna 150 can stop at idle RPM on the ground, however the stoppage could also have been attributed to carb. ice something that is normal for this engine..Cont. 0-200.
Once again I stand by my statement, a unlocked primer will not on its own cause a complete engine stoppage in flight under cruise power, where I came into this discussion.
Please do me a favour and find positive proof that shows my statement to be incorrect.
Now I hope this will end this discussion and you have a nice day.
<img src="wink.gif" border="0"> <img src="wink.gif" border="0"> <img src="wink.gif" border="0">
..................
The hardest thing about flying is knowing when to say no.
From your profile it is difficult to determine if you are a licensed, working flight instructor.
In any event I had assumed you and I are discussing the an unlocked primer causing a complete engine failure in flight in the air.
Then this morning I went back and read all the posts on this subject and I note your opinion is based on that you can extrapolate.
Flying instructors have a duty to teach and pass on information based on facts, not their ability to "extrapolate" in the discussion we are having regarding unlocked primers the facts are that a light aircraft engine such as for instance the Cessna 150 can stop at idle RPM on the ground, however the stoppage could also have been attributed to carb. ice something that is normal for this engine..Cont. 0-200.
Once again I stand by my statement, a unlocked primer will not on its own cause a complete engine stoppage in flight under cruise power, where I came into this discussion.
Please do me a favour and find positive proof that shows my statement to be incorrect.
Now I hope this will end this discussion and you have a nice day.
<img src="wink.gif" border="0"> <img src="wink.gif" border="0"> <img src="wink.gif" border="0">
..................
The hardest thing about flying is knowing when to say no.
Joined: Oct 2001
Posts: 16
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From: United Kingdom
Cat Driver,
I hav'nt read through all the previous post's but from memory I dont think anybody has said that an unlocked primer WILL on it's own cause an engine failure. What we are saying is that it MAY cause engine failure and that, if for example the mixture was already to rich this possibility is increased. As you have stated, at idle power an unlocked primer CAN cause engine failure. Why temp fate by pulling it out in flight?. Does it demonstrate anything to the student that you cant show them on the ground?.To get back to the origional question, which if I remember was should we check the primer after an engine failure, I think we are all agreed that it can at least contribute to a complete failure so YES we should check that it is locked as part of the restart drill.
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I hav'nt read through all the previous post's but from memory I dont think anybody has said that an unlocked primer WILL on it's own cause an engine failure. What we are saying is that it MAY cause engine failure and that, if for example the mixture was already to rich this possibility is increased. As you have stated, at idle power an unlocked primer CAN cause engine failure. Why temp fate by pulling it out in flight?. Does it demonstrate anything to the student that you cant show them on the ground?.To get back to the origional question, which if I remember was should we check the primer after an engine failure, I think we are all agreed that it can at least contribute to a complete failure so YES we should check that it is locked as part of the restart drill.
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stop animal testing
use taliban prisoners instead
Joined: Dec 1998
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From: Escapee from Ultima Thule
And our duty as a flying instructors is to ensure that we teach in accordance with the a/c manual.
Cessna & Piper both specify that the primer is to be locked prior to take-off. Not one of their inflight procedures specifies the use of the primer with the possible exception of an inflight restart. Don't have access to a manual to check...
Cat, to answer your (unspoken) query. No, I'm not now an instructor. I last instructed in 1999, having instructed since 1989. My instructing experience ranged from aero club to airline college; PPL, CPL, IR, night, multi, instructor, aeros and CFI positions for schools that taught these. There were also a few test approvals that came with the CFI jobs.
Cessna & Piper both specify that the primer is to be locked prior to take-off. Not one of their inflight procedures specifies the use of the primer with the possible exception of an inflight restart. Don't have access to a manual to check...
Cat, to answer your (unspoken) query. No, I'm not now an instructor. I last instructed in 1999, having instructed since 1989. My instructing experience ranged from aero club to airline college; PPL, CPL, IR, night, multi, instructor, aeros and CFI positions for schools that taught these. There were also a few test approvals that came with the CFI jobs.