TBM 700 accidents

[bookworm]

BRL has requested that the original thread I started yesterday become a condolences thread, hence I'll start a new one.

9 TBM 700 accidents in the NTSB database, including the one at Moulins. We've had two recently in the UK, at Dundee and now at Oxford. I've ridden in the TBM 700 and consider it to be a fine aeroplane, but I'm struck by some of the similarities:

1998 Truckee CA (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001211X09714&key=1) Loss of control in a night circling approach. Pilot inadvertently enters a 70-80 deg left bank. Recovers attitude but cannot avoid ground impact.

1998 Spearfish SD (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001211X10911&key=1) Loss of control on approach. "As the airplane came out of the cloud, it turned left in about a 30-degree turn. The angle of bank increased to about 70 to 80 degrees, the tail of the airplane came up, and the airplane impacted the ground nose first."

1999 Winchester VA was a gear up, no one badly hurt.

2000 Harrisburg IL (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001220X45451&key=1) Loss of control on approach. "I added power to stop the descent, however, there was a significant delay (much longer than normal) in the response of the engine. The engine finally spooled and at that moment a gust lifted the right wing and the left wing dropped, I corrected but there was not enough altitude and the left wing impacted the ground."

2001 Englewood, CO (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20010328X00660&key=1) Loss of control after departure in low IMC. "The first radar contact was at 0718:38.69, when the airplane was in a climbing left turn at an encoded altitude of 5,800 feet and at a ground speed of 109 knots. The data showed the airplane achieving a maximum encoded altitude of 7,000 feet before entering a descending left turn. The last recorded contact was at 0719:38.62 when the airplane was at 6,700 feet."

2002 Moulins, France (http://www.bea-fr.org/docspa/2002/n-ar020513/pdf/n-ar020513.pdf) Loss of control on short final "Peu avant d'effectuer l'arrondi, il estime qu'il va "être un peu court", il effectue une action à cabrer et augmente légèrement de puissance. Jugeant que l'assiette à cabrer devient trop importante il remet les gaz. L'avion s'incline à gauche. Le saumon d'aile gauche touche la raquette du seuil de piste."

2003 Aspen CO (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030221X00244&key=1) Loss of control on approach "The approach was normal until approximately 100 feet above the runway at which time the airplane encountered a turbulence condition causing rapid-roll tendencies right and left. As the student began his landing flare at about 15 feet above the runway, the left wing dropped rapidly combined with a sudden high sink rate."

2003 Leesburg VA (Prelim) (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030310X00310&key=1) Loss of control on approach. A witness reports: "The airplane then made a sharp left bank and started to turn toward the north. It continued to increase the left bank, when the nose dropped down into the trees, and the witness lost sight of it." Another reportsS: "When he looked up, he saw it exiting the clouds, about four stories above the ground, in a level attitude, headed east. The airplane then made a sharp left bank and started to turn towards the north. The nose of the airplane "was being pulled up" while in the turn. It then dropped, and pointed down toward the ground. "

2003 Mobile AL (Prelim) (http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030429X00591&key=1) Ground impact after engine shutdown. No details in the report yet.

Then we have 2003 Dundee, in which the aircraft suffers a dramatic left wing drop on final and leaves the left side of the runway (maybe WCollins can offer a comment).

Now 2003 Oxford, A witness said: "The aircraft appeared to be making a fairly normal approach at about 200-300 yards before the end of the runway. It made a level left turn and rolled to the left and then went down, almost spiralling perpendicularly."

Am I clutching at straws or is the word "left" coming up with more regularity than is reasonable?

[2Donkeys]

So the amateur investigator would perhaps conclude that the torque generated by adding a gob of power to the PT6 when the aircraft is slow and perhaps a bit nose high can easily overwhelm the pilot... It would not be a big surprise if that were the case.

[Timothy]

I don't want to say too much, but it is a matter of record that we were in the landing phase, left wing touched the ground, we turned left before hitting the water.

That's another couple of "lefts" for you.

W

[Monocock]

Could this be described as Electronic Rubber Necking?

Perhaps if the thread was started after the blinkin' wreck had been cleared away it wouldn't seem so bad.

Sorry chaps, I cant help feeling it's all a bit "bad form" this close to the incident.

Do you know who the couple were visiting for the weekend in Oxford? No, precisely.

[larrylarmor]

I think its fair to say that any pilot is keen to review the reasons why an accident might have happened, ASAP, so that they don't follow the same path.

Probably 5 or 10 different ideas come to mind about this crash, so I, for one, run through them quickly and think "would I be able to prevent or handle that scenario".

Any suggestions speculations therefore have some value. Whether the incident is 12hrs or 12 weeks old makes little difference. Reading the report is also interesting.

It is certainly part of TBM training to be aware of the need to apply a lot of right rudder to compensate for Torque when applying a lot of power for example on a go around. Many incidents involving left wing striking ground have been presumed to be caused by such a scenario. Truckee for example.

[bookworm]

Sorry chaps, I cant help feeling it's all a bit "bad form" this close to the incident.

If it's bad form to analyse accidents and attempt to learn from the misfortune of others, then I'm guilty as charged.

Do you know who the couple were visiting for the weekend in Oxford? No, precisely.

No. I didn't know them. I do know others who operate similar aircraft in similar circumstances. I can do nothing to save the couple that died yesterday. Thinking about the possible causes of accidents gives those still alive a rather better chance of remaining so.

[Timothy]

Why only commiserate with the families of those who died at Oxford? (On a point of order, Bookworm, there were three of them, not a couple.)

Why not commiserate with the families of those who died of cancer this weekend, or in action in Iraq, or in car crashes (on average there will have been more than 30 of them alone) ?

The answer is, of course, because the deaths of these people mean more to us. There but for the grace...and all that. We are interested in them and their families only because they died in an aircraft crash, not because they died per se.

If it is the aviation-related aspect of their death that touches us, and we think that we can see a pattern that might stop other such deaths, why the moritorium on discussion?

If the worry is that journos get hold of it, should we worry that, unusually, those journos have more, and more accurate, information than they usually do, thanks to Bookworm's research?

W

[Monocock]

My thread wasn't a flare and I'm glad it wasn't taken as one either. Having read what you have posted I suppose I can see where you are coming from.

In this instance it is constructive and I am probably guilty of jumping to the conclusion that it was another one of those ones like that thread about the "fuel starved Seneca at Shoreham". That thread did get me ranting as it seemed there were so many people with ridiculous theories that perhaps even verged on slanderous. When the guy was axquitted I must admit I smirked quietly.

larrylarmor's points in his first three paragraphs are very true.

I therefore retract my comments! (for the first time ever!):\

[eyeinthesky]

Without wanting to divert this thread like the original one got diverted...

Am I the only one who finds these threads offering hundreds of 'condolences' somewhat nauseating?

Any untimely death is a tragedy to those who know the victims or those connected with them, and the fact that it is an aircraft accident perhaps makes it a bit too close for comfort to this fraternity. However, why do so many people feel the need to offer 'condolences' to families of people they have never and probably will never know? It is not to make those families feel better, but in some way to make the offerers feel better.

When Princess Diana was killed, there was a massive outpouring of 'national grief' and thousands of eulogies by people who had never met, been helped by, or even seen the lady. I bet many of those were formerly as keen as many others to buy the tabloids which printed long-lens pictures of her trying to get on with her life. They found such snatched indiscretion titillating or fascinating, but suddenly, when she is dead, they join the bandwagon in saying how sorry they are and what a great lady she was.

Don't get me wrong, I'm not diminishing genuine grief, but I find it hard to understand why some feel that it is necessary to express their 'condolences' just because it is an aircraft accident. We don't see threads running offering condolences to the families of soldiers killed in Iraq or the latest victim of a road accident.

Why are aircraft accidents different, other than for reasons that they might one day happen to us? If that is the case, then discussion of the possible reasons at an early stage is healthy and has no negative impact upon the official investigation. If, by sharing our experiences, opinions or fears we can make each other a little more careful or aware of the issues and maybe prevent a future accident, then that has to be healthy. It is in no way disrespectful to those who have died. We should try to learn from their deaths, not hide behind sentimentality.

Now ducking behind the parapet...:ouch:

[John Farley]

Why are aircraft accidents different, other than for reasons that they might one day happen to us? If that is the case, then discussion of the possible reasons at an early stage is healthy and has no negative impact upon the official investigation. If, by sharing our experiences, opinions or fears we can make each other a little more careful or aware of the issues and maybe prevent a future accident, then that has to be healthy. It is in no way disrespectful to those who have died. We should try to learn from their deaths, not hide behind sentimentality.

Very well said eyeinthesky.

When the new junior pilot at an RAF 2TAF airbase in the 50's was told by the CO that there was no spare locker for him, he joined the others ouside to watch the local display ace do a rehearsal. He tentpegged in the middle of it, whereupon the JP asked "which was his locker?"

None of the other aviators was shocked. Hard maybe. They also knew it was a much softer school than it had been 10 years earlier.

[Mr Wolfie]

I too find the armchair pontificating on TBM safety in this (and the earlier) thread a little nauseating as it is so closely related to yesterdays tragedy.

W Collins following his own involvement in a TBM misshap less than two months ago asked at the time -


"I would consider it a favour if, as ever, there is no speculation as to the cause until the report comes out.

Feeling happy to be alive.
W"


I think it would have been wise and more respectful for him to have followed his own advice on this occasion too (along with a few others). I wholeheartedly support BRL putting the lid on the original thread and think that this one too ought to be kicked into touch.

Mr.W

[Timothy]

I would consider it a favour if, as ever, there is no speculation as to the cause until the report comes out.At that time I had no inkling that there might be a pattern here.

I was talking this evening to my mother (who was another pax at Dundee) who had drawn her own conclusions from what she had experienced in our crash and what she had heard on the TV about Oxford, and she was quite adamant that lessons must be learned quickly. She is all too aware what might have happened.

Obviously no-one is going to add strakes to, or ground, or whatever the TBM fleet before the formal AAIB report. But if just one TBM pilot looks at Bookworm's list and, I don't know, adds a greater gust factor, or gets more right rudder in a go-around or whatever, then it can do no harm and maybe a little good.

W

[Keef]

There is a difference, I suggest, between armchair speculation, and informed discussion. In this case, we have verified information from Bookworm, and direct experience from WCollins. If that leads to some TBM pilots being more aware of potential risks, then that's excellent. Anyone who's against that has a problem.

We'll know a lot more when the AAIB reports on these two events. Meanwhile, I (who know nothing) will refrain from speculation. But I will read avidly the input of people who know.

As to eulogies - it's a topic I'm slightly familiar with: I've probably done more of those "for real" than most folks on here. Without going into the reasons, people need to say something about a tragedy, particularly one that comes close to them or one they feel sympathy towards, or even more, one where they feel guilt. Let them be, if that's what they need.

[down&out]

I have to agree with Keef, WCollins, Bookworm & others here. Normally I keep quiet during the accident discussion threads as I don't normally have anything to add. However I do read them, and the AAIB reports, as I know I will always have plenty to learn to keep my flying as safe as possible.

I think it IS right that we, as aviators, should learn from each other and as quickly as possible. In fact, our "industry/ hobby/ sport etc" is often looked upon with respect in the way that accidents are fairly investigated by the AAIB with the aim of finding cause (and not blame) so others may learn - I know the medical profession would like to be able to emulate it...

So back to the point, if the discussion enables fellow pilots to be aware of potential issues more quickly (without undue speculation or mud slinging) and maybe prevent further incidents then great. Personally I think condolences can also be valuable, we are all human, share a love for what we done and think "there for the grace of God...". Some people prefer doing one more than the other so BRL has done us a good service by separating the threads and this thread has done well to remain pretty much focused on discussing known facts.

[IO540]

Bookwork / Keef

How about catastrophic autopilot failure (max aileron deflection)?

[2Donkeys]

IO540

With that suggestion you really are getting into pure speculation. There is something of a trend in the TBM700 world for pilots to come to grief when power is applied at low airspeed. The accidents have strikingly similar characteristics.

At first blush, the Oxford accident bears all the familiar hallmarks so that some early suspicions may reasonably be held. Once you start worrying about autopilots you are in the realms of pure speculation without basis.


2D

[Keef]

IO540

As 2D said. I know nothing about autopilot misbehaviour in TBMs and don't plan to speculate about it. My knowledge of autopilots ends with the one I use - in an Arrow III - which must be OFF below 1,000 feet. I know why it must be off, and I comply with that ruling.

I understand (from some people I respect highly) that TBMs can bite when low, that this involves left-wing-down, and that engine torque may be involved. I don't fly a TBM, and have no intention of getting into one until I've read the AAIB report on these accidents.

[Timothy]

Though I wasn't following through every detail, I don't believe the pilot engaged the a/p at any point on the flight into Dundee.

I agree that that kind of speculation is unhelpful. This does appear to be some kind of issue with control authority at low speed and high power.

W

[QDMQDMQDM]

Since this appears to be a perennial discussion of debate, I just want to add that:

a) It seems absurd to condemn such sensible discussion of accident cause such as this and, if everyone will forgive me, rather sanctimonious.

b) I too don't like these condolences threads which in the absence of direct knowledge of the people involved seem pointless and, again, rather sanctimonious. If I ever pile in, God forbid, please don't start one for me. (And if you knew me personally you probably wouldn't!)

Well done to BRL for separating the threads.

The Curmudgeon

[Circuit Basher]

QDM cubed - my sentiments precisely.

If ever I'm contained in a pile of smoking wreckage, my wishes are:

Salvage whatever is usable of the aircraft to help something else fly.
Any unusable aircraft parts should be sold as scrap to pay for the booze at a wake.
Salvage whatever is usable of me to help someone else live.
Any unusable body parts should be sold as scrap to pay for the booze at a wake. :D :D
Fill in the hole.

[Keef]

If you folks pile in, I will care! I will do what I always do in such cases (but won't post it on the Internet).

I'll even take the funeral, if you want me to (no fee for pilots!).

Meanwhile, let's keep sensible discussion going, avoid speculation, and listen to those who were involved or who know something. That might just save a life.

[Kolibear]

Keef,

Do you take advance bookings?

[Engine overtemp]

WCollins I was talking this evening to my mother .

I suggest she 'phones the AAIB and tells them what caused the accident then, as initial indications are that it was not at all similar to the incident you were involved in!!

I have to agree with Mr Wolfie and suggest that you follow your own initial reaction to the Dundee incident and wait until the facts come out!

[Keef]

Kolibear

Yep. You pick the date, I'll be there :)

[IO540]

I agree with QDM in that some discussion of possible cause is worth doing. The AAIB report can take absolute ages to come out.

Also, I've read many of these reports (the original long ones, not the summaries which the flying mags print) and in the absence of a FDR or CVR, many, perhaps most, of the fatal ones are never resolved and the report ends with several options which are merely plausible.

[BEagle]

Is there any likelihood of fin stall in a TBM 700 at low speed and inadvertant sideslip conditions - such as high power, low IAS and ball not in the middle?

This is a quastion, not a comment!

[Timothy]

If anyone still cares the AAIB Report (http://www.dft.gov.uk/stellent/groups/dft_avsafety/documents/page/dft_avsafety_027213.hcsp) is now available.

I don't think that it adds a huge amount, but I can say that it seems to me to be accurate (except that the engine is turbine, not piston. :hmm: )

Timothy

[bookworm]

I'd be interested to know how severe the yaw was before the power was applied.

[Keef]

What surprised me about the report is that there are no conclusions or recommendations. The description is what Timothy told us last year - no surprises there.

But is there an underlying problem with the aircraft type? I'd like to know. I don't think I want to fly in a TBM700 till I know that!

If it was yawing left, and full right rudder wouldn't sort it, wasn't adding power - for which right rudder input is required - likely to make things worse?

Or do the AAIB comments and recommendations come later?

[Flyin'Dutch']

Do TBMs have a Vmc?

:}

FD

[larrylarmor]

TBM700 is single engine. No Vmc (other than the 61kias stall speed)

[Timothy]

I guess that there will be more detail in the Oxford report, on account of the fatalities.

Timothy

[Phil Rigg]

----- This mesage is written from first-hand experience and in the interests of making unfamiliar pilots aware of a potential visual anomily on approach to R01/19 at Oxford/Kidlington -----

Rwy 01 at Oxford is relatively narrow for its 1200m length being only 23m wide. From experience it is easy for an unfamiliar pilot to become low and slow (and thus nose-high) on approach after becoming visual because of the non-standard aspect ratio (long and thin). After realising late in the approach this would necessitate a sudden application of significant power to regain the correct glideslope possibly leading to the postulated loss of control.

For safety, all unfamiliar pilots in all a/c should be aware of this potential visual anomily at Oxford/Kidlington.

Further, if our informed speculation here were to be true we would recommend all TBM700 pilots to practise slow stall-approach recoveries at safe altitude using a gentle application of sufficient power only and noting the IAS prior to recovery, any potential wing-drop, any opposite rudder or aileron required and the maxmium recovery height loss to be fully prepared for this potential situation on approach.

Phil

[Big Hilly]

Phil Rigg,

For safety, all unfamiliar pilots in all a/c should be aware of this potential visual anomily at Oxford/Kidlington.

A very good point indeed and a fact that is demonstrated well in THIS (http://www.airliners.net/open.file/342254/L/) photograph that I found on 'the other site'.

Best wishes,

Big Hilly

[eyeinthesky]

OK, so a chance of visual illusion with the runway length/width, but aren't the four lights on the left supposed to help you combat that (two reds, two whites being the glideslope)..?

[Big Hilly]

Up to a point eyeinthesky,

But what happens if the PAPI's are u/s?. . . . . .

Big Hilly

[Flyin'Dutch']

approach after becoming visual because of the non-standard aspect ratio (long and thin).

Two points:

1. ISTR that this happened in VMC conditions not at the end of an instrument approach so becoming visual was not an issue

2. While optical illusions can play be a factor, that is on the whole more thought to be a problem in night and marginal conditions and usually more so for the less experienced pilots.

FD

Edited to say: Doh, Larry I know that but reading between the lines; may be it needs one!

[Timothy]

Bookworm

How many of the pilots of these TBM incidents were basically heavy metal drivers, as opposed to light aircraft types?

I am pretty sure that our man at Dundee was, and I believe that the guy at Oxford may have been a 747 pilot?

Does your database access tell you such details?

Timothy

[Phil Rigg]

Many thanks for the responses. My further comments are as follows:

Big Hilly - An excellent documented example of the issue on the very runway itself! At any given approach point to a standard width (45m) runway if you are too high then the runway appears tall and thin, if on the glideslope it appears 'normal' and if too low it appears short and fat. If the runway is half the usual width then when on glideslope it will appear tall and thin and thus create the illusion of being to high causing an unfamiliar pilot to want to descend below the glideslope to recreate the 'normal' picture. This is exacerbated further during daylight at Oxford because the asphalt is actually 1535m long by only 23m wide even though the licensed runway length is shorter, due to displaced thresholds, thus further enhancing the tall and thin perception.

eyeinthesky - It is widely recognised and taught during training that an inexperienced pilot can fly low on a visual approach at night due to an optical illusion even with the PAPIs fully operational. The above illusion I have pointed out is less well known and taught and thus can catch-out the very experienced but unfamiliar pilot who usually operates from standard aspect ratio runways. That is why I have published this warning for Oxford/Kidlington.

Flyin'Dutch' - I do not now whether the pilot of the accident flight was conducting a visual or an instrument approach, however, regardless of the approach at some point it became visual with the possibility of an experienced but unwary pilot being caught-out by the above illusion.

Timothy - Would the above thoughts be behind your asking Bookworm if he can confirm the experience levels of the prior accident pilots?

Phil Rigg - I must learn to spell anomaly!

With due respect to all,

Phil

[Timothy]

Phil

Isn't it funny how we bump into each other every decade or so? Must pass the news onto Topsham (where they have all returned as if the rest of their lives never happened....maybe it didn't, really) :p

Funnily enough my thought about pilot experience arose earlier in the evening than when I read your thoughts. Mine were more along the lines of whether someone who is used to flying big jets would make different instinctive control inputs during a go-around or other power burst from someone more schooled in torsional and propwash effects. It was only an idle thought based on what little I know of the background of the Dundee and Oxford pilots.

I do think, however, that you might be onto something; it's a clever thought.

Incidentally the hard runway at Shoreham has a similar illusion, whereas Manston is rather the opposite as it is soooo wide!

Get in touch when you are on the mainland sometime.

Timothy

[tmmorris]

Being based at Oxford I have the opposite problem quite often - getting better with experience, but the first time I went somewhere wider (Duxford, I think it was) I tried to land about 2ft above the runway and came down with rather a thump when it stalled finally!

Tim

[Phil Rigg]

For information, after experiencing 20° port wing and nose drops when approaching the clean stall in a TBM 700C2 flight test published in March 2004 Pilot magazine, author Peter Turner states:

"Recovery was satisfactory but I couldn't help feeling that if power was added too quickly the torque might just exacerbate the wing drop further."

He goes on to comment in the dirty stall that:

"..... departure came at 60 (kts), this time with a more pronounced nose and port wing drop."

I think the factory needs to do some work on this one. It would be interesting to discover how many of the accident a/c had a weather RADAR raydome as this is mounted on the port wing. If I was a designer knowing that engine torque would cause a port wing drop I would at least stack all items that contribute to asymmetry on the starboard wing!!

Phil

[TonyR]

I had a flight in a TBM 700 a few years ago.

I was in the right seat, the pilot on aproach behind a PA28 at about 90 knots.

We were quite light with 3 pob and were gaining on the PA28

He allowed the speed to get to about 80 knots at about 2 miles from touchdown and the aircraft began to "sink", the pilot applied quite a lot of power and the aircraft banked left over 30 degrees before he recovered, we also lost over 100 feet.

The pilot had 4500 hours with over 200 hours on type but had never experienced this before. but I could tell he was very concerned about the experience.

Yes there was a radar raydome fitted

[2Donkeys]

I don't think you need to go as far as to blame the Wx Radar Pod.

The issue that seems to be quietly acknowledged by Socata relates to the condition in which the aircraft is allowed to become slow and settles back into a Tail-Down flight attitude. At this point, the directional stability of the aircraft is weaker than is desireable in any case, and the combined effect of the torque and slipstream should significant power need to be applied are enough to do the rest. As a result, TBM pilots are actively being encouraged/re-educated to fly approaches whilst retaining a modest amount of torque in an attempt to avoid the syndrome. The combination of the power lever at flight-idle and a low and slow approach is a bad one.

I don't think anybody is really suggesting that the positioning of the radar pod has anything to do with this.

2D

[Phil Rigg]

2D

Thanks for the info regardng encouraging TBM 700 pilot recurrent type training. This is obviously the first point of action and the fundamental issue here is the torque/slipstream effect in slow flight with a nose-high attitude and the power at flight-idle.

However, my radome comment was not entirely flippant. When an a/c enters its marginal flight envelope approaching the stall any asymmetry has a more significant effect. For example, in a stall any asymmetry will cause one wing to drop, with the potential of entering a spin, whereas a symmetrical a/c will more likely experience a wings level nose drop/mush down.

Thus having entered the slow, nose-high and approaching stall part of the envelope any asymmetrical drag-inducing elements will aid recovery after power application on the starboard wing rather than worsen recovery on the port wing. The difference between the two alternatives being the degree of challenge the pilot would experience between the two cases and I know which one I would prefer!

Thanks again for your information.

Phil

[bookworm]

The AAIB report on the TBM 700 fatal accident at Oxford that started this thread has now been published (http://www.aaib.dft.gov.uk/publications/bulletins/may_2005/socata_tbm_700b__n30lt.cfm).