Propeller Striking Passenger Exiting Piper Tomahawk

[The Heff]

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 (http://www.aaib.gov.uk/publications/bulletins/october_2011/piper_pa_38_112_tomahawk__g_otft.cfm).

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?

[Big Pistons Forever]

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?

One cause of the low volt light being on could be that the starter bendix has not disengaged after the engine started. In other words the starter motor is still trying to turn the prop. This will cause a massive draw of power and result in the low voltage light staying on. This situation can be verified by looking at the ammeter. If the starter is still engaged and the engine is running the ammeter will be pegged at + 60 amps as the charging system tries to keep up with the massive draw of power. Damage to the starter and electrical system will occur quickly so it is important that the engine be immediately shut down.

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

[BackPacker]

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.

Sure you're not confused with the "Low Oil Pressure" warning light?

[S-Works]

How do you not notice a turning prop?

[IO540]

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.

[The Heff]

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.

[mad_jock]

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.

[24Carrot]

I suggest you have some time to yourself in the cockpit and just go through all the lights and gauges ...

If you take some photos of the panel, you can go through them at home as well.

[fireflybob]

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.

Surely you mean the starter solenoid energised light which should extinguish after you release the starter key and if not a shutdown should be made immediately.

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.

[Pilot DAR]

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:

...... 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.

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!

[Them thar hills]

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....

[stevelup]

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.

[Jan Olieslagers]

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 focused more on the "Over voltage" warning light to my understanding it is rather the UNDER-voltage light that is getting such a lot of unwonted interest.

[S-Works]

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.

[The Heff]

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!

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.

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.

Passenger safety is totally the pilot's responsibility!

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?

[RTN11]

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.

[mad_jock]

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.

[Gertrude the Wombat]

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.

[EddieHeli]

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.

[The Heff]

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 didn't really want to 'read between the lines' of the AAIB bulletin report, but I can't help thinking that both the pilot and the passenger were in a rush, and the differing stories indicate a bit of a 'blame game'.

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.

[pasir]

On a related thread the Cessna 337 Skymaster with props front and rear offers a double hazard. I seem to recall that there was a tragic accident many years ago where one of the passengers on a 337 for reasons I cannot recall exited the a/c while engines were running and was beleived to have assumed it was safe to cross to the rear - and walked straight into the spinning prop.

...

[piperarcher]

On a few occasions I have been in the left hand seat, with the engine on idle, while an instructor or fellow pilot have got it. I guess for me, I considered this to be acceptable as instructors have done this (as IO540 mentions when doing solo's etc). However, its one thing when the person getting in and out is a fellow pilot and is very familiar with the dangers, and has the sense to make sure they exit behind a wing or any object that could hit them if the brakes became free, and another allowing a non-pilot with no aircraft experience to do so.

A very unfortunate accident, and something which in hindsight makes one think about any future change overs with a idle engine.

[Big Pistons Forever]

re the original headline: I would suggest that the universal SOP is a non pilot passenger should never get out of an aircraft with the engine running and if a pilot is going to get out of a passenger seat with the engine running then the PIC would brief the pilot passenger so everyone understood what actions he would expect the pilot passenger to do including making sure none of the seat belts got left outside and he would close the door with the PIC responsible for locking it, and finally the passenger would exit out and to the back and give a thumbs up when he was clear and it was safe for the aircraft to manoever

With respect to the electrical issues which are also being discussed, I have never seen a C 150/152 with a "starter engaged" warning light. Is this a UK unique requirement ?

Finally I miss read the original post and thought he was talking about a C 152. The later 1982 and up vintage C 152's have a low voltage light but No C 150 ever came from the factory with one.

However the 1970's vintage L and M model C 150's do have an "over voltage" light. This is connected to a over voltage sensor which, in the event of an over voltage condition being detected, will automatically disconnect the alternator from the electrical system, by removing the field current. The electrical system will now be powered only by the battery. Illumination of the light indicates the over voltage sensor has activated. Of note the charging system can fail without the light illuminating, if for example the alternator were itself to stop producing current, The only sure way to know that the electrical system is functioning correctly is to monitor the ammeter.

[mad_jock]

I am racking my brains on that one BPF.

I suspect that and the low voltage light have been a compulsory ADD for some 11 years now. I am sure A and C can confirm or say I am talking rubbish. They have always both looked like an addition in all light aircraft I flown on G reg. The N reg ones I have flown haven't had either.

And as for walking forward in a tommy the door would get in the way for a start you would struggle to get round it with the prop wash even if at idle so something smells fishy to me anyway.

[RTN11]

With respect to the electrical issues which are also being discussed, I have never seen a C 150/152 with a "starter engaged" warning light. Is this a UK unique requirement ?Yes it is. All SEP aircraft have it in the UK - there should be a UK supplement in the back of the POH stating the requirement.

You end up with 3 lights - one for starter engage, one showing the alternator isn't working and one showing low bus voltage.

And as for walking forward in a tommy the door would get in the way for a start you would struggle to get round it with the prop wash even if at idle so something smells fishy to me anyway.

Agreed, but I'm assuming they shut the door first and then stepped off the front of the wing. How you wouldn't notice the spinning prop is beyond me.

If they were in a hurry, it wouldn't of helped. Not being too experienced probably means everything was done relatively slowly and from the checklist which may mean they didn't want to go through all the faff of getting the thing going again. A tommy restart is simply mixture rich, throttle crack, master switch on, turn the key, not the 50 or so checks listed.

[Gertrude the Wombat]

Would it be a sensible assumption that the pilot and the passenger were in a rush?
Possibly.

Yet another opportunity for accident avoidance? If I find myself getting into a rush around aeroplanes I quite deliberately stop, calm down, think, and go back a few steps in case I've missed something.

I've never yet got to the point of deciding "I'm not in the right mood for this, I'm going home" but I've heard of other people doing it and I'm aware it's an option.
A tommy restart is simply mixture rich, throttle crack, master switch on, turn the key, not the 50 or so checks listed.
Yes well, I got caught once doing the equivalent of that in a 172. The bit I missed out on the restart was making sure the fuel tap was pointing the right way.

[mad_jock]

Agreed, but I'm assuming they shut the door first and then stepped off the front of the wing. How you wouldn't notice the spinning prop is beyond me.

Aye but you would have to shove it open, then get out with it pushing against you which would put you halfway down the wing anyway towards the trailing edge. Why on earth would you then head forward again?

If you stayed on the black walkway you would be inside the prop disk, you wouldn't just get your arm taken off. You would needed to have headed out from the door at 30degrees plus.

Personally I think the PAX is at it for the insurance claim. Either that or Darwin is at work.

[AdamFrisch]

The more I hear about it, the more I think old Ted Smith was right when he designed the Aerostar; One of the big gripes about that airplane is that the entry to the cabin is via the pilots door with the pilot's seat slid back, but I bet nobody has walked out onto a spinning prop in that aircraft and hurt themselves.

[abgd]

Also baffled as to how one might not be viscerally aware of a turning propeller.

Perhaps if there was a nearby plane going full-throttle as a distraction, it would be easier to neglect the fact that your own aeroplane was making an engine-noise and spinning blades on the front.

It would be an odd sort of a scam, but there is a precedent:

2002 Darwin Award: Chainsaw Insurance (http://www.darwinawards.com/darwin/darwin2002-01.html)

[Big Pistons Forever]

The more I hear about it, the more I think old Ted Smith was right when he designed the Aerostar; One of the big gripes about that airplane is that the entry to the cabin is via the pilots door with the pilot's seat slid back, but I bet nobody has walked out onto a spinning prop in that aircraft and hurt themselves.

No but several pilots have lost fingers when then stuck their hand into the spinning prop while reaching up to close the top half of the clamshell door.....

[osmosis]

"First flight in a light aircraft..."
It appears the pax briefing, if any, was not understood or retained by the pax for it to be functional. The pilot wasn't aware (enough) and the pax wasn't effectively briefed (enough).

It can also happen to the most experienced; a story was told to me years ago of a jackaroo who used to be a regular spotter in a Bell 47G during mustering. The heli pilot and jackaroo had flown together quite a lot and the latter had been told when he exited the RHS of the heli he had to walk forward away from the rotor blades each time so the pilot knew he was out of danger from the tail rotor. The two regularly flew together and this became a matter of routine for them both. But on one occasion they were mustering in a fixed wing and after landing the same jackaroo exited the RHS and, you guessed it, walked forward straight into the spinning propeller. If I was told how it all ended up I have long since forgotten but my point is pax are the innocent and ignorant parties; nothing is to be assumed.

[OpenCirrus619]

Also baffled as to how one might not be viscerally aware of a turning propeller.

A number of years ago I would have agreed with you ...

Having held a PPL for a number of years I would hope I was aware of propellors.

I was at the launch point at a gliding club, waiting to "run wing" for an aerotow launch, when another glider landed and blocked the runway.

While waiting for the other glider to be moved I was chatting to the tug (Super Cub) pilot (tug engine running). I was standing just in front of the strut as it was the easiest place to stand to get my head close to his - made necessary because of the engine noise. After a couple of minutes the tug pilot asked me to check progress on the runway ...

To this day I don't know, if the tug pilot had not grabbed my arm, whether I would have walked through the prop disc. Still makes me go cold thinking about it.

OC619

[onetrack]

"First flight in a light aircraft", pretty much says it all. A totally unknowledgeable young woman, completely oblivious to the method of operation of mechanical devices, steps out onto the wing, totally focussed on going to the control tower, which she can see directly ahead, to get her forgotten headset. The spinning prop would not even have registered with her.

Add in the common failure of many younger people to not listen properly, to what was said by the pilot, and this was an accident that was sure to happen.
Possibly an additional factor was impetuousness, also a common fault in many younger people.

What the pilot failed to do was to fully and thoroughly impress upon the passenger, the extreme danger posed by the rotating propellor.
It's a danger easy enough to envisage to anyone with mechanical knowledge, but not to a person who has never been around anything mechanical.
The pilot was possibly also struggling with the many tasks required on takeoff, as a low hour pilot, with only 2 hrs logged in the previous 90 days, and 144 hrs in total on type, and failed to place a high priority on passenger education.

The passenger survived, she had her arm sewn back on in a 10 hr operation.

Warning to pilots after woman struck by propeller at RAF Henlow - News - The Comet (http://www.thecomet.net/news/warning_to_pilots_after_woman_struck_by_propeller_at_raf_hen low_1_1107148)

[fireflybob]

Another relevant point is that pilots are not nearly as "propeller aware" as they were in the days when we had to hand swing aircraft and pull the prop through a few times to "suck in" as in DH Gypsy Major engine etc.

Students would have to be checked out on "hand swinging" - this made one very aware of the hazards!

When you have someone involved who is not "aircraft aware" you have to do all the thinking for them. As an instructor there is no way I would have let a person whose flight was the first in a light a/c enter and/or exit with the prop running.

The responsibility for this sad mishap rests squarely with the pilot although I would also be looking at the training she received as a significant factor.

[rusty sparrow]

Disarm the engine, not the passenger.

Hope she made a full recovery - not an excusable accident!

[IO540]

Very much agree with onetrack above...

[Captain Smithy]

A gruesome incident with thankfully a lucky ending for the passenger, could have been much much worse!

Have always been aware of the dangers of props, always remember the unsubtle posters at airfields when I was in the Air Cadets warning of the dangers, that and common sense telling me that a whopping great metal thing spinning at 2500rpm is to be treated with some tactful caution & respect. :uhoh: :ouch:

Smithy

[Echo Romeo]

To this day I don't know, if the tug pilot had not grabbed my arm, whether I would have walked through the prop disc. Still makes me go cold thinking about it.

OC619

That line makes my blood run cold reading it:ouch:

[Sir George Cayley]

Having watched a young girl walk through a propellor arc all I can say it can happen, has happened and probably will happen again. We should discount the female pax coincidence.

I can recall the sound of metal and bone as if it was yesterday. I can also see the anguish on the pilots face straight after.

It must be some sort of human factor that differentiates between passengers and pilots I think.

The C337 tragedy happened at Liverpool many years ago when confusion between the pilot and marshaller resulted in the pax offering to go speak to him. She was both cabin crew and girlfriend of the pilot and I think it was the front engine's prop she walked into.

SGC

[Captain Smithy]

Jeez that's a pretty horrendous tale Sir George. Disturbing stuff and a lesson to all. :yuk:

[benppl]

Any info on the Liverpool accident?