Metroliner Wheels Up Landing YBBN
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If you look really closely at the photo you will see the flaps are down. I don't believe hydraulics had anything to do with it, and in any case, and as mentioned, the gear would have been able to free fall once the uplocks were released.
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to the pilot for a successful landing - it would have been a big challenge completing all of the above single pilot. I'm glad people have avoided so far the argument "props shouldn't have been feathered". In the Metro it isn't about preserving the engines or parts, rather about avoiding further damage to systems (which may cause a fire!) and its occupants.
A bit of aluminium, few rivets, it will be just like a new one.
Aimpoint, thanks for pasting the old manual extracts.
Propeller blades contacting the surface while turning under
power tend to disintegrate and throw shrapnel which may
puncture the fuselage. Blades contacting the surface when
feathered, or nearly feathered, will bend slightly and wear away
but most likely will not shatter and will aid in holding the wings
and nacelles off the runway.
power tend to disintegrate and throw shrapnel which may
puncture the fuselage. Blades contacting the surface when
feathered, or nearly feathered, will bend slightly and wear away
but most likely will not shatter and will aid in holding the wings
Sorry though I cannot agree with that course of action.
There are many factors to consider in any given situation of course however the chances of rotating blades under idle power breaking up and throwing some shrapnel and the damage likely to be caused by that is far less than the catastrophic damage to the airframe that will occur if a feathered prop possibly digs into the ground if on a dirt strip (and it can even happen on a paved runway).
In that case the entire engine being ripped off its mounts and the airframe and possibly taking the wing with it and opening up the fuel tanks are far far worse.
Sadly this has happened many times before.
It thankfully didn't in this case though.
Airframes have been totally destroyed and lives lost by feathering before wheels up landings that otherwise would not have been had they let them hit and bend under idle power.
Often this has been done under the misguided belief by the pilot that he can minimize the damage to the aircraft, engines, props etc.
The cost of new props ,engines and some airframe repairs is usually less than a total write off.
There doesn't need to be a long debate ( or any at all, I don't want one) about what I have stated, some will agree, some simply wont. It is just my opinion based on things I have seen and heard from old veterans.
So what you're saying, is that you should contravene what the flight manual says?
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That's ok, some people just know more than the manufacturer.
What a load of rubbish! That takes this week's pprune bullsh!t award.
There are many factors to consider in any given situation of course however the chances of rotating blades under idle power breaking up and throwing some shrapnel and the damage likely to be caused by that is far less than the catastrophic damage to the airframe that will occur if a feathered prop possibly digs into the ground if on a dirt strip (and it can even happen on a paved runway).
In that case the entire engine being ripped off its mounts and the airframe and possibly taking the wing with it and opening up the fuel tanks are far far worse.
In that case the entire engine being ripped off its mounts and the airframe and possibly taking the wing with it and opening up the fuel tanks are far far worse.
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Propeller blades contacting the surface while turning under
power tend to disintegrate and throw shrapnel which may
puncture the fuselage.
power tend to disintegrate and throw shrapnel which may
puncture the fuselage.
the chances of rotating blades under idle power breaking up and throwing some shrapnel
Thanks for the insult FTS, much appreciated.
As I said my opinion based on what I have seen and been told, you are entitled to your own. (without insulting me)
No I am not claiming to know more than a manufacturer at all.
They have have stated an opinion re possible shrapnel damage and an opinion of a piloting technique to be used in a given circumstance. They did not mention the possible alternative I did in the manual.
I remember the B1900 photo, not the details of the incident.
Any casualties due shrapnel damage?? was that on runway or earth, cannot tell from pic??
The plane skidded to a halt intact.
As i stated if they were feathered and had "dug in" or however you want to describe it on either runway or earth the entire engines would have most likely been ripped from the airframe etc as I stated in previous post.
In the past going back since their invention most metal props have tended to bend back on impact and maybe shed a tip or blade rather than totally shatter and disintergrate as appears in that photo.
As I said my opinion based on what I have seen and been told, you are entitled to your own. (without insulting me)
No I am not claiming to know more than a manufacturer at all.
They have have stated an opinion re possible shrapnel damage and an opinion of a piloting technique to be used in a given circumstance. They did not mention the possible alternative I did in the manual.
I remember the B1900 photo, not the details of the incident.
Any casualties due shrapnel damage?? was that on runway or earth, cannot tell from pic??
The plane skidded to a halt intact.
As i stated if they were feathered and had "dug in" or however you want to describe it on either runway or earth the entire engines would have most likely been ripped from the airframe etc as I stated in previous post.
In the past going back since their invention most metal props have tended to bend back on impact and maybe shed a tip or blade rather than totally shatter and disintergrate as appears in that photo.
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IIRC it was a undercarriage shuttle valve failure so they flew to the main base (Wellington?) and burnt off some fuel before landing on the main (sealed) runway. The props shattered on contact with the ground and peppered the fuse / cabin with shrapnel. Someone else will know more, but I seem to recall the pre-crash prep included moving pax out of the seats that aligned with the props. There is a video of the event on utube.
Some aircraft POH include shutting down engines and feathering, some state shut down and don't feather, some don't shut down. I suspect that the people who build the aircraft make those determinations for reasons based on knowledge of the airframe and systems and I am inclined to follow their instructions. Also my liability insurance requires that I do.
Some aircraft POH include shutting down engines and feathering, some state shut down and don't feather, some don't shut down. I suspect that the people who build the aircraft make those determinations for reasons based on knowledge of the airframe and systems and I am inclined to follow their instructions. Also my liability insurance requires that I do.
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True, you're entitled to your opinion, but just how many feathered props have you seen "dig in"? I'm not an engineer but I reckon the blades would shear off before digging in on Tarmac and causing the wings to snap off.
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Jams mate, not just your insurer.Reg's require adherance to flight manual procedures as well. Be a brave man standing in a coroners court trying to defend why he didnt adhere to manufacturers recommended procedures. Your rather lucky in NZ in that you have coherant, sensible, and understandable Regs, unlike OZ.
Anyone else out there experiencing bullying by CASA FOI's to depart from AFM procedures or manufacturers recommended, and insert their opions as to how it should be done??
Could be just me, but seems to be happening all the time now.
Its a bit worrying where you would stand legally if you aquiess to their demands and something went wrong. Would it give the insurance company an excuse not to pay out, and if they didnt would CASA cover your costs?
Anyone else out there experiencing bullying by CASA FOI's to depart from AFM procedures or manufacturers recommended, and insert their opions as to how it should be done??
Could be just me, but seems to be happening all the time now.
Its a bit worrying where you would stand legally if you aquiess to their demands and something went wrong. Would it give the insurance company an excuse not to pay out, and if they didnt would CASA cover your costs?
It's an interesting debate this one, feathered V rotating, shame that the subject can't be discussed rationally! I see little point in insults, that achieves nothing.
I do believe though that the general consensus is or was many years ago that feathering a prop/s just prior to shut down in these situations was considered more dangerous than leaving the prop spinning.
Some of the thinking behind this was the increased work load (actual reaching for the pitch lever/s & taking yr eyes off the flight path) right at a critical stage of the ldg & the sudden change in noise & performance in doing so even if only in an auditorial (made up word) form. Another was what has been suggested here already, a feathered prop has a far greater 'leverage' capability due to it being stronger presented to an obstruction edge on than a spinning one meaning it could dig in & cause sever damage & possible loss of airframe integrity before the event is over (A/C stopped).Obviously once the prop/s where/was feathered you have zero options but to land.
Both scenario's can have the same results, a prop/s that has disintegrated has lethal capabilities.
At the end of the day I personally would consider both options taking into account the surface to be used for landing, Emerg services avail, A/C type, prop to ground clearance with gear retracted and the type of fuel on board not to mention. the ease of escaping from the fuselage.
The POH may very well indeed suggest either way but they (the manufacturers) aren't in it !
Someone mentioned insurance recourse if the POH is not followed, damn litigation these days is more dangerous than the event itself!
So keep the debate alive guys but lets keep it civilized hey?
Wmk2
I do believe though that the general consensus is or was many years ago that feathering a prop/s just prior to shut down in these situations was considered more dangerous than leaving the prop spinning.
Some of the thinking behind this was the increased work load (actual reaching for the pitch lever/s & taking yr eyes off the flight path) right at a critical stage of the ldg & the sudden change in noise & performance in doing so even if only in an auditorial (made up word) form. Another was what has been suggested here already, a feathered prop has a far greater 'leverage' capability due to it being stronger presented to an obstruction edge on than a spinning one meaning it could dig in & cause sever damage & possible loss of airframe integrity before the event is over (A/C stopped).Obviously once the prop/s where/was feathered you have zero options but to land.
Both scenario's can have the same results, a prop/s that has disintegrated has lethal capabilities.
At the end of the day I personally would consider both options taking into account the surface to be used for landing, Emerg services avail, A/C type, prop to ground clearance with gear retracted and the type of fuel on board not to mention. the ease of escaping from the fuselage.
The POH may very well indeed suggest either way but they (the manufacturers) aren't in it !
Someone mentioned insurance recourse if the POH is not followed, damn litigation these days is more dangerous than the event itself!
So keep the debate alive guys but lets keep it civilized hey?
Wmk2
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You've hit the nail on the head Thorn Bird.
If there's a procedure for the emergency in the AFM/POH then follow it to the letter. If not the PIC will be a lamb to the slaughter in the eyes of the regulator and, worse, the insurance company. CASA approve checklists for this very reason. To 'encourage' crew to do it by the book. And rightfully so.
"....damn litigation these days is more dangerous than the event itself!".
How true.
D
If there's a procedure for the emergency in the AFM/POH then follow it to the letter. If not the PIC will be a lamb to the slaughter in the eyes of the regulator and, worse, the insurance company. CASA approve checklists for this very reason. To 'encourage' crew to do it by the book. And rightfully so.
"....damn litigation these days is more dangerous than the event itself!".
How true.
D
Wally, THANK YOU VERY MUCH, ALL MY POINTS SPELLED OUT EXACTLY.
You have expanded out exactly what I was thinking and tried to say briefly in a few paras without going into too much detail.
Everybody please reread Wally's post again carefully, word for word.
To emphasize a few points he stated very clearly,again--
The prop does have far greater strength and leverage edge on if it hits anything from soft ground to the pavement or any kind of resistance to forward motion. I have seen the wreckage from such an event on a number of occasions.
Once feathered your options are all gone, except to land.
A crew consideration of all relevant factors should be considered at the time.
Blind adherence to flight manual procedures or rather "recommendations" in this case is not always the safest or smartest course of action.
The manufactures are most certainly not aboard nor do they get to pay the price when / if it goes badly wrong.
Most aircraft have never actually been landed wheels up by the test pilots during type certification flights. Just like they haven't actually ditched them, nor is it required. (IIRC)
AFM procedures in many such cases are "recommended", based on best possible "guessed outcomes" in certain scenarios.
The engineers Best guesses/estimates" are certainly not always right by any stretch!!
(Eg NASA and Rockwell engineers, ALL of them, considering the Q of leading edge damage to shuttle wings in the event of being hit by foam on launch etc had decided that max damage would possibly be a few scratches a few mm deep IIRC from the investigation reporting at the time, NOT a massive hole as was the case in the actual event.
When they did fire a piece of foam at a flight certified leading edge panel, same as actually damaged one at whatever speed it was they were ALL STUNNED by the totally devastating results, a massive hole, compared to what they had "estimated".
As something I read just last week stated, "A series of actual tests is worth hundreds of expert opinions" )
I am not talking about trying to rewrite a "systems based procedure", eg what to do and what order to do certain items like in a specific electrical system problem for eg, thinking I know the system better than the engineers who designed it etc etc.
Nor saying I can just disregard an outright AFM WARNING such as -" Do not pull power levers below Flight Idle in flight or loss of the aircraft will result", such as has been discussed at length in the Dash 8 Crash thread.
ThornBird, Your statements also very true.
Too many lawyers and regulators too interested in litigation and prosecution after an accident instead of trying to learn from it and make whatever changes may be required to try and prevent a recurrence.
As I said before, my opinions, based on what I have seen and been told by far "older and bolder pilots" than me over the past 30 yrs. Just trying to put forward other views based on past tragic events so they hopefully may not be repeated by others who have never heard of them or even considered them.
Cheers all.
You have expanded out exactly what I was thinking and tried to say briefly in a few paras without going into too much detail.
Everybody please reread Wally's post again carefully, word for word.
To emphasize a few points he stated very clearly,again--
The prop does have far greater strength and leverage edge on if it hits anything from soft ground to the pavement or any kind of resistance to forward motion. I have seen the wreckage from such an event on a number of occasions.
Once feathered your options are all gone, except to land.
A crew consideration of all relevant factors should be considered at the time.
Blind adherence to flight manual procedures or rather "recommendations" in this case is not always the safest or smartest course of action.
The manufactures are most certainly not aboard nor do they get to pay the price when / if it goes badly wrong.
Most aircraft have never actually been landed wheels up by the test pilots during type certification flights. Just like they haven't actually ditched them, nor is it required. (IIRC)
AFM procedures in many such cases are "recommended", based on best possible "guessed outcomes" in certain scenarios.
The engineers Best guesses/estimates" are certainly not always right by any stretch!!
(Eg NASA and Rockwell engineers, ALL of them, considering the Q of leading edge damage to shuttle wings in the event of being hit by foam on launch etc had decided that max damage would possibly be a few scratches a few mm deep IIRC from the investigation reporting at the time, NOT a massive hole as was the case in the actual event.
When they did fire a piece of foam at a flight certified leading edge panel, same as actually damaged one at whatever speed it was they were ALL STUNNED by the totally devastating results, a massive hole, compared to what they had "estimated".
As something I read just last week stated, "A series of actual tests is worth hundreds of expert opinions" )
I am not talking about trying to rewrite a "systems based procedure", eg what to do and what order to do certain items like in a specific electrical system problem for eg, thinking I know the system better than the engineers who designed it etc etc.
Nor saying I can just disregard an outright AFM WARNING such as -" Do not pull power levers below Flight Idle in flight or loss of the aircraft will result", such as has been discussed at length in the Dash 8 Crash thread.
ThornBird, Your statements also very true.
Too many lawyers and regulators too interested in litigation and prosecution after an accident instead of trying to learn from it and make whatever changes may be required to try and prevent a recurrence.
As I said before, my opinions, based on what I have seen and been told by far "older and bolder pilots" than me over the past 30 yrs. Just trying to put forward other views based on past tragic events so they hopefully may not be repeated by others who have never heard of them or even considered them.
Cheers all.
Last edited by aussie027; 23rd Feb 2012 at 11:31.
I hate to add to all this pedantry but an important point with any aeroplane fitted with Garrett TPE-331's is that at idle power the props are still doing the same rpm as at full power, there's just less torque happening.
The props also don't stop all that quickly when you pull the stop & feather knob due to the inertia of the big prop, gearbox, and engine.
Anyway, just follow the flight manual unless there's something unusual that would require a change to that procedure. And never rush .... unless you have no choice.
The props also don't stop all that quickly when you pull the stop & feather knob due to the inertia of the big prop, gearbox, and engine.
Anyway, just follow the flight manual unless there's something unusual that would require a change to that procedure. And never rush .... unless you have no choice.
Would different procedures apply with free turbine engines such as the PT6 compared to fixed shaft such as the TPE331 ?
Wouldn't the PT6 automatically feather when shutdown due to loss of oil pressure where as the TPE331 would have to be manually feathered ? My turboprop days where quite a while ago.
Wouldn't the PT6 automatically feather when shutdown due to loss of oil pressure where as the TPE331 would have to be manually feathered ? My turboprop days where quite a while ago.
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I think this event's successful outcome of feathering the props at an appropriate time shows the manufacturer knows what it is talking about and pilots shouldn't rely on hearsay. The props didn't dig in or rip the plane to pieces. Different procedures for different aircraft of course, but we should never pretend to know more than Mr. Swearingen, Mr. Beechcraft etc., particularly during times of high stress.
Common sense applies though - it would have been unlikely for the pilot to have one prop already feathered and one ready to go if the weather was down to the minima.
Common sense applies though - it would have been unlikely for the pilot to have one prop already feathered and one ready to go if the weather was down to the minima.
Feathered
vs.
Not feathered
Sorry bout the double up.....
