Propeller Striking Passenger Exiting Piper Tomahawk
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Propeller Striking Passenger Exiting Piper Tomahawk
Reading about this propeller-related accident at RAF Henlow got my attention, because it amazes me that the pilot asked her passenger to vacate the aircraft whilst the propeller was still turning.
AAIB Bullentin Report available here.
I remember being told during my own flying training (albeit on a Cessna 150) that if the 'Low Voltage' warning light remained lit, then the engine should immediately be shut down. I've not looked at a Piper checklist for sometime, but I believe that this is the same. Can shutting down the engine immediately after start cause damage to the engine, and how?
AAIB Bullentin Report available here.
The pilot had been told during training that, in order to protect the engine, she should not shut down immediately after start and so, instead, she reduced the power to idle before the passenger stepped onto the wing.
I remember being told during my own flying training (albeit on a Cessna 150) that if the 'Low Voltage' warning light remained lit, then the engine should immediately be shut down. I've not looked at a Piper checklist for sometime, but I believe that this is the same. Can shutting down the engine immediately after start cause damage to the engine, and how?
A more likely reason for the low volt light to be on is that the charging system is not charging. This can be verified by the ammeter showing a slight discharge. An increase in RPM should be tried to see if the situation changes, but most probably there is a fault in the alternator or voltage regulator. You will not be going anywhere with no charging system so you will have to shut down and snag the aircraft but there is no hurry for the shutdown.
I am disappointed that your instructor did not explain all this during your training
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I remember being told during my own flying training (albeit on a Cessna 150) that if the 'Low Voltage' warning light remained lit, then the engine should immediately be shut down.
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I am not aware of any reason why a piston aircraft engine cannot be shut down soon after starting.
This is a really pointless accident, more horrid because the woman passenger probably got her arm chopped off. No pilot should let somebody get out with an engine running, unless the person getting out clearly knows what he or she is doing.
On my first solo, the instructor did a few circuits with me, and then got out with the engine still running, but obviously got off to the rear and not towards the prop. In fact I did my "first solo" twice (because I changed schools c. the 20hr point) and the 2nd instructor also got out with the engine running.
This is a really pointless accident, more horrid because the woman passenger probably got her arm chopped off. No pilot should let somebody get out with an engine running, unless the person getting out clearly knows what he or she is doing.
On my first solo, the instructor did a few circuits with me, and then got out with the engine still running, but obviously got off to the rear and not towards the prop. In fact I did my "first solo" twice (because I changed schools c. the 20hr point) and the 2nd instructor also got out with the engine running.
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I'll check next time I'm in the cockpit of a C150 but I'm sure its a 'low voltage' warning light. I don't think there is a warning light for low oil pressure, just a gauge next to the temperature gauge.
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There is a low voltage light your not going mad its yellow. And there is also a starter light as well which is linked to the a relay which is engaged when the starter is engaged it should be red.
Low voltage light isn't a reason to get excited.
But there is no great worry if it is showing after start especially if you are at idle rpm instead of 1200rpm. It should go off when sitting at 1200rpm.
It means that there isn't 14V in the electrics which means the battery isn't charging from memory it triggers under 13Volts. Which in the grand scale of things for PPL is a very good reason to shut down and get another plane. Basically once the battery runs out of juice you won't have any electrical instruments or radios. Nothing stopping someone in the know from getting airborne turning the master switch off and turning it on again at the other end to get the aircraft to a maint shop in class G.
Again if it comes on in the air just tell which ever ATS your talking to what your plans are and what the issue is then turn the master switch off and continue and turn it on again 10mins out from where you are going to land.
The red starter light means the starter motor is still engaged and all matter of nasty things can happen including the aircraft going on fire. If this is the case and you should shut down ASAP.
I suggest you have some time to yourself in the cockpit and just go through all the lights and gauges and then have a list of all the warning lights and then find out how each of them works and what they are telling you and what happens when they go on.
As for what the pilot had been told about shutting the engine down its another one of those urban flying school myths which has been twisted from its initial purpose into utter ****e.
Starting the plane multiple times in a short period can flatten the battery because you don't give it a chance to recharge (crap flying school batteries are more prone to this)
If the engine has been sat over night there won't be any oil on the moving parts and thats when most wear occurs. Once the oil is warmed up it isn't such an issue.
Low voltage light isn't a reason to get excited.
But there is no great worry if it is showing after start especially if you are at idle rpm instead of 1200rpm. It should go off when sitting at 1200rpm.
It means that there isn't 14V in the electrics which means the battery isn't charging from memory it triggers under 13Volts. Which in the grand scale of things for PPL is a very good reason to shut down and get another plane. Basically once the battery runs out of juice you won't have any electrical instruments or radios. Nothing stopping someone in the know from getting airborne turning the master switch off and turning it on again at the other end to get the aircraft to a maint shop in class G.
Again if it comes on in the air just tell which ever ATS your talking to what your plans are and what the issue is then turn the master switch off and continue and turn it on again 10mins out from where you are going to land.
The red starter light means the starter motor is still engaged and all matter of nasty things can happen including the aircraft going on fire. If this is the case and you should shut down ASAP.
I suggest you have some time to yourself in the cockpit and just go through all the lights and gauges and then have a list of all the warning lights and then find out how each of them works and what they are telling you and what happens when they go on.
As for what the pilot had been told about shutting the engine down its another one of those urban flying school myths which has been twisted from its initial purpose into utter ****e.
Starting the plane multiple times in a short period can flatten the battery because you don't give it a chance to recharge (crap flying school batteries are more prone to this)
If the engine has been sat over night there won't be any oil on the moving parts and thats when most wear occurs. Once the oil is warmed up it isn't such an issue.
Last edited by mad_jock; 31st Oct 2011 at 15:54.
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I suggest you have some time to yourself in the cockpit and just go through all the lights and gauges ...
I remember being told during my own flying training (albeit on a Cessna 150) that if the 'Low Voltage' warning light remained lit, then the engine should immediately be shut down.
The low voltage light is something else but they are not the same thing.
So long as people are trained and qualified and properly supervised doing a running change in a PA38 should not present any undue hazard.
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Respecting that this thread is titled Propeller striking....
It seems however to be focused more on the "Over voltage" warning light, as a contributing factor... Referring to the C150/152/172 system (but I'm sure that the Tomahawk is very similar), I do not agree with:
The alternator can have some variability in it's low speed (RPM) efficiency. If the Low voltage light is not indicating at high idle to flying power engine speeds, and your ammeter is not showing a discharge, the plane is fine. If it is indicating at mid range RPM, you should expect to see a discharge on the ammeter also (though a small discharge can be hard to distinguish). Landing light on, and increase RPM (during run up is a good time for this). If you now see a discharge, then take the plane back, you do have a fault. Try cycling the alternator side of the master switch if it is split.
If in flight, you have an alternator failure, (ammeter discharge indicated, LV light on), with some economizing of electrical load, and a decent battery, you have a half hour of flying with no problem.
You will not hurt the engine running with the LV warning light on - for any length of time - it's approved to run that way. (many of these engines have direct ancestors who were in aircraft with no electrical systems). You just won't have battery charging going on. I have not seen oil pressure warning lights on these aircraft, but if you have an illuminated low oil pressure warning (some STC'd instruments have this function), then yes, on the ground, shut down with no delay. In flight, plan for an engine failure soon, unless you're content to shut it down and forced approach from where you are.
Few aircraft have "starter lights" but they are a great idea. If you have one, and it is warning you of a stuck starter contactor, shut down right away.
As for not shutting down right after a start, no problem. If you would like to leave it running for any appropriate reason, keep non pilot passengers inside with you. ANY time I allow a pilot passenger to exit with the engine running, I'll turn the aircraft so their exit path is away from the turning prop, and still remind them about the running propeller.
Passenger safety is totally the pilot's responsibility!
It seems however to be focused more on the "Over voltage" warning light, as a contributing factor... Referring to the C150/152/172 system (but I'm sure that the Tomahawk is very similar), I do not agree with:
...... It should go off when sitting at 1200rpm.
It means that there isn't 14V in the electrics which means the battery isn't charging from memory it triggers under 13Volts. Which in the grand scale of things for PPL is a very good reason to shut down and get another plane.
It means that there isn't 14V in the electrics which means the battery isn't charging from memory it triggers under 13Volts. Which in the grand scale of things for PPL is a very good reason to shut down and get another plane.
If in flight, you have an alternator failure, (ammeter discharge indicated, LV light on), with some economizing of electrical load, and a decent battery, you have a half hour of flying with no problem.
You will not hurt the engine running with the LV warning light on - for any length of time - it's approved to run that way. (many of these engines have direct ancestors who were in aircraft with no electrical systems). You just won't have battery charging going on. I have not seen oil pressure warning lights on these aircraft, but if you have an illuminated low oil pressure warning (some STC'd instruments have this function), then yes, on the ground, shut down with no delay. In flight, plan for an engine failure soon, unless you're content to shut it down and forced approach from where you are.
Few aircraft have "starter lights" but they are a great idea. If you have one, and it is warning you of a stuck starter contactor, shut down right away.
As for not shutting down right after a start, no problem. If you would like to leave it running for any appropriate reason, keep non pilot passengers inside with you. ANY time I allow a pilot passenger to exit with the engine running, I'll turn the aircraft so their exit path is away from the turning prop, and still remind them about the running propeller.
Passenger safety is totally the pilot's responsibility!
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Expensive low volts warning.
On an 0-200 or C90 the generator drive is in the accessory gearcase along with mag drive gears and starter drive. Not a good place to have metal debris from a sheared generator drive shaft. A rare event maybe, but I've known it happen.
Generator light on at much more than idle may indicate a failure such as this....
Generator light on at much more than idle may indicate a failure such as this....
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As an aside, I wouldn't have thought the ammeter is any use in these circumstances as the power to the starter motor does not pass through it and the solenoid itself is unlikely to make much of a deflection.
No indeed, but the starter will draw such an awful lot of current from the battery that the alternator will supply every amp it can muster to make up for the loss. And that "charge" current does pass by way of the am(p)meter.
as for
to my understanding it is rather the UNDER-voltage light that is getting such a lot of unwonted interest.
as for
focused more on the "Over voltage" warning light
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An interesting and yet utterly pointless diversion from the original incident. An incident that was totally avoidable regardless of the state of any flashing lights.
A passenger inexperienced in light aircraft operation should not have been allowed to get out of the aircraft with the prop running unless being met and guided by a responsible person outside the aircraft.
Regardless of the pilots claims on briefing the passenger they should have made them sit there until the engine was shut down or as above the passenger was supervised.
The whole incident was avoidable and inexcusible.
A passenger inexperienced in light aircraft operation should not have been allowed to get out of the aircraft with the prop running unless being met and guided by a responsible person outside the aircraft.
Regardless of the pilots claims on briefing the passenger they should have made them sit there until the engine was shut down or as above the passenger was supervised.
The whole incident was avoidable and inexcusible.
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My mistake, I meant the red starter light! Sat behind my computer, I incorrectly thought it was the Low Voltage warning I was thinking of. I'll follow mad_jock and 24carrot's advice about re-familiarising myself with the C150 and PA-28 panel!
I thought this would probably be the case, because I couldn't think of any mechanical reason why starting up the engine and promptly shutting down would cause any substantial damage.
I also agree with Pilot DAR's conclusion, and am confident that in this situation I would have shut the engine down prior to the passenger's departure. I'd like to think that I would have walked with them back to the control tower to obtain the second head-set, rather than let them wander about airside on their own!
I'm still getting used to my new aeroplane, which is a vintage hand-start design; which has already taught me lots of new things about propeller safety and engine ignition systems!
However, judging by the differing recollections by the pilot and the passenger, I wonder if they're still friends?
Originally Posted by mad_jock
As for what the pilot had been told about shutting the engine down its another one of those urban flying school myths which has been twisted from its initial purpose into utter ****e.
Originally Posted by Pilot DAR
Passenger safety is totally the pilot's responsibility!
I'm still getting used to my new aeroplane, which is a vintage hand-start design; which has already taught me lots of new things about propeller safety and engine ignition systems!
However, judging by the differing recollections by the pilot and the passenger, I wonder if they're still friends?
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As part of a pre-flight brief, as well as how to operate hatches and harnesses, you should always include that you must ALWAYS vacate the aircraft by opening the door and exiting to the REAR as the propellor may be spinning, emergency vacate or not.
There's no reason to ever step off the front of the wing. This just highlights the need to brief passengers who are not familiar with aircraft.
This also highlights the fact that inexperienced PPL pilots will blindly follow the advice of instructors. I have never known anyone say not to shut an engine down soon after starting. I have seen instructors with 10s of thousands of hours do it, seen engineers do it, and do it myself. This PPL may never have read the POH, and is just going on advice given years earlier.
I'm thinking perhaps the pilot had seen the same instructor jumping out with the engine running while he sent them solo, and therefore thinks it's the norm. Perhaps I will start including this as totally unacceptable practice for passengers in my post-course brief.
There's no reason to ever step off the front of the wing. This just highlights the need to brief passengers who are not familiar with aircraft.
This also highlights the fact that inexperienced PPL pilots will blindly follow the advice of instructors. I have never known anyone say not to shut an engine down soon after starting. I have seen instructors with 10s of thousands of hours do it, seen engineers do it, and do it myself. This PPL may never have read the POH, and is just going on advice given years earlier.
I'm thinking perhaps the pilot had seen the same instructor jumping out with the engine running while he sent them solo, and therefore thinks it's the norm. Perhaps I will start including this as totally unacceptable practice for passengers in my post-course brief.
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Must admit I am guilty as charged for jumping out engine running sending folk solo. Also getting in engine running after picking me up after refuelling for a post solo NAV sortie.
I think I will also change my ways. If the instructor never does it it will never be seen as acceptable or normal.
I think I will also change my ways. If the instructor never does it it will never be seen as acceptable or normal.
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This discussion is (largely) silly and completely beside the point.
Are there really clubs whose flying order books do not include "no running changes" (with the possible exception of the instructor getting out for a change from dual to solo)?
Do they really manage to leave their customers with the idea that following some not-understood engine management procedure takes precedence over safety? What's worse, destroying an engine or destroying a person?
Should it not occur to a pilot that if someone needs to get out and the engine can't be shut down yet (not matter how falsely that belief is held) the correct procedure is to sit there and wait until the engine can be shut down?
Are there really any pilots whose passenger briefing does not include fairly explicit briefings as to why the passenger should not go anywhere near a propellor?
I'm sure I've missed some, so there must be more than just four reasons why such accidents shouldn't happen.
Are there really clubs whose flying order books do not include "no running changes" (with the possible exception of the instructor getting out for a change from dual to solo)?
Do they really manage to leave their customers with the idea that following some not-understood engine management procedure takes precedence over safety? What's worse, destroying an engine or destroying a person?
Should it not occur to a pilot that if someone needs to get out and the engine can't be shut down yet (not matter how falsely that belief is held) the correct procedure is to sit there and wait until the engine can be shut down?
Are there really any pilots whose passenger briefing does not include fairly explicit briefings as to why the passenger should not go anywhere near a propellor?
I'm sure I've missed some, so there must be more than just four reasons why such accidents shouldn't happen.
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This is one of the reasons I don't like aircraft with the step in front of the wing, such as the RV12, and don't understand why manufacturers design them like this.
I don't believe it is sensible to get into the habit of exiting via the wing leading edge, because it might happen instinctively when exiting another type and accidents such as this may happen.
Even if the prop isn't turning it can cause injury if you were to stumble into it when getting down from the wing.
I don't believe it is sensible to get into the habit of exiting via the wing leading edge, because it might happen instinctively when exiting another type and accidents such as this may happen.
Even if the prop isn't turning it can cause injury if you were to stumble into it when getting down from the wing.
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Originally Posted by Gertrude the Wombat
Should it not occur to a pilot that if someone needs to get out and the engine can't be shut down yet (not matter how falsely that belief is held) the correct procedure is to sit there and wait until the engine can be shut down?
Are there really any pilots whose passenger briefing does not include fairly explicit briefings as to why the passenger should not go anywhere near a propellor?
Are there really any pilots whose passenger briefing does not include fairly explicit briefings as to why the passenger should not go anywhere near a propellor?
Would it be a sensible assumption that the pilot and the passenger were in a rush? Rather than shut the engine down, impatience and bad judgement got the better of the pilot and she did what she thought was sensible and throttled back to idle. Could the excitement and sense of haste cause the passenger to forget what she was told about how to safely exit the aeroplane and think the fastest way down was to head forward off the leading edge?
It seems too much like common sense to stay away from the propeller; common sense indeed for anyone familiar with SEP aircraft. Yet both the pilot and the passenger's action were in their opinion sensible at the time.