beechnut;
Well, I don't think so. I tried AvWeb, AirDisaster etc as well, although I think it's shut down- anyone? Al Wheeler was there and a few others - good guys from AVSIG etc, (anyone know what became of Randy Sohn?).

The quality of the input here, even given the M-Factor so delicately put by an honorable member is without equal in terms of breadth/depth. Others may differ but it is here that experts in their aviation/technical fields come first; - I truly don't think many here are verbal or mental whatever's although there seems enough wet dreams to last for a while...

That fertile ground overgrows with weeds that drive out healthy plants is a fact of life everywhere - some seeds are lucky to find sunshine and flourish, others wither. I find patience is more rewarded than giving up in frustration although there are times...:ugh:

I'm a little bit apprehensive about straying into postulations (since posts have a way of haunting one) but just musing at the end of the day.

Accepting the reasonable explanation for one reverser deployed as stated in today's posts (one reverser MELed and the other deployed at first re-contact with the ground)

I am left with an aircraft either with insufficient speed or insufficient configuration to climb out of ground effect. A lack of speed has time to be noticed while a misconfiguration is a gotcha after you "set power" and if the gotcha is not annunciated during the takeoff roll then it is often a fatal flaw as NW255 and Delta at DFW demonstrated.

I do not yet see convincing evidence that too little speed was present (after all it did lift off in ground efect) although ground tract radar and/or useable DFDR data may answer this more positively

As in NW255 the DFDR would clearly show flap configuration and unlike NW255 it has not been leaked yet into the public domain.

Then there is the damage impact marks of the actuation for the flaps and slats and typically in spite of fire damage some of it remains on one side or the other to confirm their position at impact.

I suspect that people very close to the investigation allready have some very positive clues for and against many of the theories postulated on this board.

lomapaseo;
I think so. And here we begin to enter the territory which Sidney Dekker discusses so well in his "Field Guide for Understanding Human Error"..."hindsight". In fact, the entire thread is a wonderful lesson in "determining cause" both in accidents and in human affairs, isn't it? We don't know, so we each draw on our experience, our prejudices, our history and our training. As you say, very soon, many posts will be seen as, "having been prescient", (very likely without good reason except luck and some good guessing!), and others will be dumped into file 13 and the next round of rabbit trails will begin..."Why did the crew....? etc" in terms of "attempted rejects", "retracted slats/flaps", etc, etc etc.

The key in the end is Dekker's point: What made sense to the crew at the time such that they made the decisions that they did? And if those who posited the various scenarios about returns to the gate, including some very poignant and bluntly honest posts I recall, how will, if shown to be the case, will "the killer items" be dealt with from here on in?

I have no trouble picking the berries from the vines, although I have gotten pricked from time to time. I agree that the depth (if you can draw it out) far surpasses any other forum listed so far.

That way if I happen to rub elbows with experienced investigators I can ask intelligent questions and actually understand their brief answers.

I'm worried about this (general statement). These are very rare and engender a "it won't happen to me because I know better" In the NW and Delta events it was my strong conviction that it was human traits common to all of us that initiated the event. That's why we put in additional barriers.

For me, I'm going to ask most of my questions in the end, why did the barriers not work? It is very valuable teaching tool and I am going to stress it to a higher degree.

I have an extreme unliking of a machine that is not tollerant of the pilot to the point where it throws a "gotcha" at you.

Some more information thrown around by the press (a TV channel in this case). As usual, it shouldn't be taken as too accurate.

-First point of impact: 20m away (to the right) from runaway.
-Altitude reached by the airplane: no more than 15m (previous visual estimation of only 7m was given to the judge).
-After take-off, it "turned" (deviated from a straight line) 25º (previosuly thought to be more like 35º)
-It took two seconds since it started to go down until it hit the ground. (Consistent with prior reports that it took between 6 and 7 seconds from the moment the wheels left the ground til the plane touched it again, say 4s going up and 2s coming back down).
-As previously reported, the right engine reverser is now said to have been locked-out-of-service for 3 days (MEL, up to 10 days). The LEFT engine reverser seems to have been found properly deployed.

TR Deactivation
 

In the media reports regarding TR deactivation or in any other reports, has there been any mention of WHICH engine? If #2 the causal TR theories are less valid? However, if it was the #2 engine which seperated on initial impact, the pictures earlier in the thread show that the TR was deployed, suggesting the #1 engine was the one with deactivated TR. Although, of course, the TR could still have deployed on impact even if deactivated?

Media reporting the news speaks cathegorically of RIGHT engine reverser locked out of service for maintenance. But then only say that "AN engine" was found with the reverser properly (fully) deployed. That "an engine" does not imply it was only ONE engine nor that it was THE OTHER engine.

So nobody can tell for sure from that report, but casual reading of that article, in one of Spain's large TV stations web page, would lead you to believe that, i.e, the pilot could not possibly had deployed the right reverser because "it didn't work" and that he deployed the left one to try to brake (they actually go as far as claiming that that was the case).

Can someone positively ID which one is the engine shown on the picture with the reverser deployed?

Could the experts elaborate if a 25º "turn" to the right could be accomplished from a (hard-ish) roll (no yaw) of only a few (say 3) seconds? The witnesses speak of what possibly was a roll to the left followed by a "steep" roll to the right after becoming airborne and before hitting the ground. Airplane is said to have been airborne for 7s max total.

Here is another tragic reverser deployment during takeoff!

ASN Aircraft accident Fokker 100 PT-MRK São Paulo, SP TAM F-100 in Conghonas, Brazil - 1996

A dreadful accident! As much as the Dr Reason stuff has made me want to reach for my gun in the past, this accident could be the poster for the next 10 years.

I fly a variant of the MD82. The members talking no flap and pilot commanded TR deployment (with one locked out) know what they are talking about.

A return to the gate and subsequent go go go from ground people are pressures.

Operators still using the aircraft (not sim) for training have mostly trended away from abbreviated checklists for circuits and make every landing a full stop

Several posters have mentioned that one of the TRs was locked out (and I guess MEL'd) some time prior to this flight. Is this normal practice with MD aircraft? I would have thought it more normal to lock both out if one is U/S.

PJ2: AirDisaster has been re-ignited as airdisaster.info by some former members. Wild speculations are the order of the day.
Per

Taxi2parking

no, we don't disable both TR's if only one is broken. we are however very careful when we use just ONE.

taxi2parking, consider, if we have an engine failure prior to V1 on an airplane with all thrust reversers working, and we elect to deploy thrust reversers to aid us in stopping, only ONE will be providing reverse thrust, as the other engine is already dead. to be sure, we get some drag by deploying even a dead engine reverser.

so one is better than none. but we are limited by controlability in the amount of reverse thrust used.

ALSO...AIRBUBBA, thanks for telling us about that bizare continued takeoff in the face of a blaring warning horn...yikes.

There is a terrible trend in modern airline training to just teach enough about a plane to get a pilot to pass a checkride. In depth knowledge of your plane seems to be an antiquated concept. And yes, its all about money.


I voiced a theory regarding ground shift, thinking the plane was airborne, etc many,many pages ago. I still think it is right (except for that brief phony cvr bit).

I encourage all pilots to make sure they practice safe flying and never trust a warning system to save them. Get paranoid if you have to, be "MR. MONK" and be compulsive and check your flaps a couple of times before takeoff (landing too)

Certainly the LAPA and Helios accidents showed a lack in training concepts and methods as warning horn sounds (take-off config, cabin altitude) where never heard by either crew members before. This should be the first thing in the sim, how the horn sounds.

The 3 Killers
 

PJ2:
I think I know where you are going with this. It is apparent from earlier posts by highly experienced pilots such as yourself, that the three killers at TO are already informally re-checked again immediately prior to takeoff. Given that confiuration related accidents are far from infrequent, would it be desirable and/or feasible to formalise this final check?

This policy is also depending on local authority regulations. Since the S7 778 accident in Irkutsk, the Russian AR-IAC does no longer allow to disable T/R asymmetric. So either you disable two T/R, or you are not going to fly. Traditionally the Russians did not know an MMEL, so it is only possible for western type aircraft to disable anything and still fly.

Some more elaboration from the media in Spain.

August 17th (3 days before the accident) the airplane was subjected to a revision by two company technicians after the RIGHT engine showed a diagnosis light on the reverser (more precisely , the electronic control system to deploy it), according to documentation given to the judge. Some anomaly on a valve on the hydraulic system involved with the device was found as the cause. No leaks could be found.

It's unclear at this point (conflicting reports) if the fault was (thought to be) fixed or if the repairs were delayed and the reverser locked-out of service. Most sources speak of the item repair being delayed and the pilots knowing about it and unable to make use of the device, other (one source) speaks of it having been fixed. Regardless, everyone agrees it wasn't necessary to have it working for the flight (both airstrips were long enough).

The reverser has appeared deployed on that RIGHT engine according to most sources, while one major newpapers explicitly RETRACTS the previous information and now says that it was the LEFT engine that was found with the deployed reverser.

Of course it could've been deployed on purpose while on the ground and trying to brake, or become loose from the impacts, etc.

Aiport ground radar data was reviewed and found the airplane to reach 170kt (error marging up to 30km/h). Regardless, seemed to have reached enough speed to rotate and lose contact with the ground.

That same plane had an aborted T/O less than a month ago by another pilot flying Mallorca-Copenhagen because he observed "excessive noise from the landing gear".

Incidents related to performance calculations
 

I cite these two previous incidents below simply to show that it is surprising how large an error in performance calcs a crew will accept. (I'm the author of the first of the stories.)

Some posts above have suggested that an error in V speeds of sufficient magnitude to cause this accident was inconceivable. I'm not implying I have any insight into whether this was a factor at Madrid or not - but I do think these incidents make it clear that the notion is not out of the question.

Somebody out there may know whether the procedures/kit used by Spanair are the same as SAS, which I think is likely given their commercial/operational relationship. And you may have opinions on the subtle factors at play with the trend to uplinked weights and/or V speeds.


SAS probes procedures after close call on take-off
Kieran Daly, London (03Sep99, 12:16 GMT, 759 words)

SAS is reviewing its cockpit procedures after a Boeing 767 came close to catastrophe on take-off when the crew used the wrong aircraft weight for its performance calculations.

The captain of the Tokyo-bound 767-300ER aborted take-off at Copenhagen after rotation when he realised something was wrong and managed to stop inside the length of the airport's 3,570m (11,713ft) runway 22R from a speed of around 140kt (260km/hr).

The aircraft suffered a minor tailstrike and burst tyres and it has since been established that the crew had entered the aircraft's zero fuel weight (ZFW) instead of its gross weight - about a 65t difference.

SAS, which recently changed its procedure for calculating take-off speeds - switching from using a hand-held computer in the cockpit to the use of the ACARS (aircraft communications addressing and reporting system) datalink to have the final calculation performed elsewhere - is now trying to see if there is a way to reduce the chance of a repetition.

A senior Captain involved in the review tells ATI: "This happened to a very experienced professional colleague of mine. My first thought was that if this can happen to a solid fellow like this then it can happen to anyone. So we have to look into it and see what we can do."

Another SAS official - director of flight operations in Denmark, Fleming Jeppsson - relates how in the 24 August incident the co-pilot was conducting the take-off and rotated the aircraft at the calculated speed (VR).

Jeppsson says: "The take-off data computation was based on far too low a take-off weight. So that gave a very, very low V1, V2, and VR and when the rotation was performed it did not give the desired results. The aircraft over-rotated and there was a tailscrape although it turned out to be not bad enough to warrant changing the skid.

"The captain realised that something was wrong and told the co-pilot to lower the nose. All the indications told him to carry on, which is what they are told to do, but he realised something was wrong and he aborted the take-off."

Remarkably the aircraft suffered only a scraped tailskid and three of four tyres burst on the left main landing gear, requiring the tyres and brakes to be replaced. Jeppsson says some passengers did not immediately even realise anything was amiss.

The SAS captain explains that since implementing ACARS some six months ago, SAS' procedure on the 767 fleet is for one pilot to enter the data for the calculations into the flight management system datapage and for both pilots to verify the inputs and the results.

The data entered comprises the aircraft's actual gross weight as passed to the crew, the wind, temperature, altimeter setting and runway condition. That is transmitted via ACARS to SAS operations' department and, within about 20s, the calculated flap setting, full thrust, derated thrust if possible, and speeds are transmitted back and printed out in the cockpit.

Before the introduction of ACARS, the SAS 767 fleet was using hand-held "take-off calculators" in the cockpit to calculate the same data - a major advance on the paper charts used by airlines for decades.

The SAS captain says: "The charts gave us very exact but very conservative figures so the calculator was a great step forward and ACARS is even better. I don't think I would want to revert to the old system."

Because the old chart system required the use of very conservative assumptions it actually constrained the loads that aircraft could carry at marginal airports, meaning the switch to computed solutions had a direct effect on operating efficiency.

Both SAS officials confirm that, although the Swedish investigation authorities are examining what happened, there is no question that it was the crew that made the error and not the operations staff.

Jeppsson says: "As soon as we identify the weak area then my idea would be to immediately correct it. But we don’t want to change a procedure or anything like that until we know exactly what we want to do.

"We have sent a message to pilots to say that obviously this is a grey area to put it mildly. It seems like something very basic but clearly it can happen."

What is certain is that SAS would be extremely reluctant to reduce the use of ACARS itself - it has been a hugely enthusiastic user of the system and datalink programme manager, Bjorn Syren, publicly identified its role in take-off calculations as "a big success" at an ARINC symposium in May.
Source: Air Transport Intelligence news


Pilot error blamed for SIA's Auckland tailscrape
Nicholas Ionides, Singapore (16Dec03, 01:08 GMT, 525 words)


A severe tailscrape incident on takeoff involving a Singapore Airlines (SIA) Boeing 747-400 at Auckland International Airport in March was caused by basic crew errors that resulted in a slower-than-required rotation speed, according to New Zealand accident investigators.

New Zealand’s Transport Accident Investigation Commission (TAIC) says in its final report that a takeoff weight transcription error led to a miscalculation of the takeoff data, which resulted in a low thrust setting “and excessively slow takeoff reference speeds”.

It says the rotation speed had been mistakenly calculated for an aircraft weighing 100t less than the actual weight of the 747-400, which suffered substantial damage to its lower rear fuselage.

As a result the rotation speed was 33kt (61km/h) less than the 163kt (302km/h) that was required for the aircraft. When the captain rotated the aircraft for takeoff the tail struck the runway “and scraped for some 490m until the aeroplane became airborne”.

The TAIC says in its report that the 49-year-old captain, who has since left SIA, had 12,475hr of flying experience at the time but only 54hr on the 747-400, as he had just converted from the lighter Airbus A340-300.

One of two first officers on board had 223hr of flying time on the 747-400 and only 1,309hr in total. The other “was a qualified and very experienced first officer”, with around 3,386hr on the aircraft type.

None of the 369 passengers or 20 crewmembers on board the aircraft was injured. The ten-year-old 747-400, registered as 9V-SMT, was operating as flight SQ286 on 12 March 2003, bound for Singapore. The crew returned the aircraft to Auckland after takeoff and made a successful overweight emergency landing.

“The system defences did not ensure the errors were detected, and the aeroplane flight management system itself did not provide a final defence against mismatched information being programmed into it,” says the TAIC.

“During the takeoff the aeroplane moved close to the runway edge and the pilots did not respond correctly to a stall warning. Had the aeroplane moved off the runway or stalled a more serious accident could have occurred.”

It adds: “The aeroplane takeoff performance was degraded by the inappropriately low thrust and reference speed settings, which compromised the ability of the aeroplane to cope with an engine failure and hence compromised the safety of the aeroplane and its occupants.”

The TAIC says “safety recommendations addressing operating procedures and training” were made to SIA, while a recommendation concerning the flight management system was made to Boeing.

Star Alliance carrier SIA says in a statement that the TAIC’s safety recommendations “have been, or are being, implemented in full”, adding that it is “sorry that pilot error prior to the takeoff led to this aviation occurrence”.

“The emergency procedures followed by our pilots led to the aircraft returning to Auckland safely a short time later with no injuries to passengers or crew. The safe return is a reflection of the pilots’ training and good airmanship,” it says.

“We wish to assure our customers that the lessons from this occurrence and arising out of this thorough investigation by the TAIC have been learnt and several procedural changes have already been implemented.”


Source: Air Transport Intelligence news

Excellent, this shows very clearly that the plane was going in a much straighter line than one would have thought. One small correction: What you have marked as "Debris A" is almost certainly a car on the runway.

I wonder if the statements about a slow take-off roll can give any clues to the "wrong take-off configuration" hypothesis.

IF the flaps and slats were retracted, one would expect the acceleration to look normal (possibly even slightly better) until the airplane is rotated (at a speed below Vr for the no-flaps configuration). From there on the acceleration would suffer due to the nose-up angle and ensuing high drag, prolonging the long ground roll before finally becoming airborne (as it briefly did).

IF on the other hand the take-off configuration was okay and the airplane still had a longer than normal take-off roll, then it would point to a thrust deficit below commanded thrust, and the abnormally slow take-off roll would be apparent already before it rotated.

The question is then, did the witnesses comment on a slow take-off in the early stages of it, or only after rotation? Anyone seen such statements?

A sub-question for the second case: What faults would possibly cause a thrust decrease and still not show up on the engine instruments or alarms?