Incident at Airport Dortmund (Germany)

[IFixPlanes]

Airport Dortmund (Germany) is temporary closed.
A B737-800 operated by Air Berlin (AB 2450) overrun the Runway.
All Passengers (165) unharmed according Dortmund Airport Homepage (in german):
Startseite - Dortmund Airport (http://www.dortmund-airport.de/dortmund_airport.html)

Pictures (source http://www.blaulichtreporter.de/):
http://www.blaulichtreporter.de/garbage/16/169645/12357769.jpghttp://www.blaulichtreporter.de/garbage/16/169645/12357772.jpg
http://www.blaulichtreporter.de/garbage/16/169645/12357774.jpghttp://www.blaulichtreporter.de/garbage/16/169645/12357779.jpg
http://www.blaulichtreporter.de/garbage/16/169645/12357783.jpghttp://www.blaulichtreporter.de/garbage/16/169645/12357791.jpg

[Vrqs]

This morning 07.05 LT Flight AB 2450 aboarded T/O and came to a rest on a field behind the runway. According to the airport nobody was injured. 165 Pax on board.

TORA: 2000m

Actual METAR / TAF:
METAR: EDLW 030750Z 02010KT 2000 -SN OVC005 M05/M05 Q1018
short-TAF: EDLW 030530Z 0306/0315 02008KT 1000 SN OVC003 BECMG 0307/0310 3500 -SN BR BKN007 TEMPO 0310/0315 BKN012

www.blaulichtreporter.de (http://www.blaulichtreporter.de)
Startseite - Dortmund Airport (http://www.dortmund-airport.de/)

[eagle21]

Edlw 030550z 02008kt 1000 R06/1800d Sn Ovc003 M04/m04 Q1016 06snoclo=edlw 030520z 03008kt 1000 R06/1900n Sn Ovc003 M03/m03 Q1016 06snoclo=
Edlw 030450z Vrb02kt 1000 R24/p2000d Sn Sct001 Ovc002 M01/m01 Q1016 24snoclo=
Edlw 030420z Vrb01kt 1200 R24/p2000n -sn Br Bkn002 Bkn007 M01/m01 Q1015=

General news
03.01.2010 Air traffic at Dortmund Airport abandoned
At 7 o’clock this morning, an aircraft by airberlin (flight AB 2450, to Las Palmas/Gran Canaria) went off the runway during takeoff.

All 165 passengers are unharmed and will continue their journey from a neighboring airport.

The recovery of the aircraft is in progress. Until close of works the air traffic at Dortmund Airport is abandoned.

Incoming and outgoing flights must be deleted or redirected to other airports.

[747JJ]

EDLW has a history of overruns both TO and LDG. Runway is relatively short and stop margins with Airbus A320 with Conf 3 in the 30 to 60 meter region with WET RWY with medium weights and engine anti-ice on. TOGA thrust provides much better margins but it is still a short runway and many companies operating in and out have put restrictions as to who can be the pilot flying. Both RWY's 24 and 06 also have a displaced threshold.

[klm-md11]

EDLW has a history of overruns both TO and LDG. Runway is relatively short and stop margins with Airbus A320 with Conf 3 in the 30 to 60 meter region with WET RWY with medium weights and engine anti-ice on.

- except it was not an A320 but a 737.

Looking at the picture it seems to be a -800 with a collapsed nosegear, but not nearly as bad as the AA 737-800 of last week!

She'll be back flying...:ok:

KLM-MD11

Edited for a typo - I'm not a native English speaker, you see...;)

[76-er]

Anyone seen a runway state message or snowtam yet?

I have a feeling we're gonna see this one in some CRM recurrent course in a few years..

[747JJ]

I was aware of it being a 737. Same laws of aeromystics apply to a Boeing as it does to the Airbus. Since I have not been flying a 737 for over 10 years and certainly not to DTM but have on the Airbus, hence the example.

I would think that AB320 and B737 have very similar RWY performance out of DTM. Certainly they have same problems with friction coefficient and runway state and face same problems with weather even possibly with similar results.

[eagle21]

Why not passenger evacuation? I can see some steps attached to the 2R door. In most airlines an abnormal attitude such as this would generate an evacuation started by any cabin crew member without the need to wait for instructions from the flight deck.

[TheWanderer]

A short report on N-TV: Flughafen Dortmund gesperrt: Air-Berlin-Jet rutscht ab - n-tv.de (http://www.n-tv.de/panorama/Air-Berlin-Jet-rutscht-ab-article661929.html) (in German)

The report says 165 passengers on board, nobody hurt.
Pax left the airplane by stairs.

Air Berlin sieht keine Fehler bei ihrem Piloten. "[Er] hat korrekt gehandelt", sagte Sprecherin Diane Daedelow. Er habe den Start wegen zweier unterschiedlicher Geschwindigkeitsanzeigen im Cockpit abbrechen müssen. Anscheinend sei einer der Tempomesser der Boeing 737-800 nicht in Ordnung gewesen. Air Berlin prüft nun, ob Versäumnisse des Flughafenbetreibers vorliegen. "Es ist die Frage, ob der Ausrollweg vollständig enteist wurde", sagte Daedelow.
Translation:
Air Berlin does not see pilot error. He did correct, said Air Berlin speaker Diane Daedelow. He had to abort the takeoff due to two different speed indications. Apparently one of the speed indicators was wrong. Air Berlin is now checking for failure of the Airport Operator. It is questionable if the stopway was completely deiced, said Daedelow.

[gb777]

Direct link:

Galerie Doro WIEBOLD TVnews GmbH - WIEBOLDTV AKTUELL (http://www.blaulichtreporter.de/)

Apparently rejected take-off / All pax and crew safe

[txl]

Here's some more information gathered from press reports: AB2450 (a 737-800) was scheduled to take off from Dortmund for Las Palmas at 7:05 this morning. 165 pax and 6 crew on board (as well as a dog in cargo, as one report says).

Citing airport officials, reports say that the pilot aborted take-off due to "technical irregularities". Aircraft "skidded" off the runway and came to stop nose-down on an adjacent field. According to one report, the aircraft, while trying to brake, veered off the side of the icy safety area.

All pax and crew (as well as the dog) are unharmed and left the aircraft via stairs.

Reports cite an Air Berlin spokeswoman saying that the pilot had to abort take-off because of two differing speed readings from cockpit instruments. There seems to have been a problem with the aircraft's speed indicators.

According to an news agency report, the airline asked whether the safety area had been properly de-iced.

Aircraft not damaged, says the airline. Dortmund airport closed until aircraft is recovered. Pax continue journey via Paderborn.

[HermanTheGerman]

http://img163.imageshack.us/img163/7306/008ijo.jpg
http://img197.imageshack.us/img197/1862/015rwo.jpg
http://img163.imageshack.us/img163/5425/026qy.jpg

[despegue]

If they overran the runway, they must have been doing more than 80kts. Why then stop for an airspeed indication problem? You have to be go-minded, the aircraft almost always feels better in the air, except for engine and flight-control problems obviously.
Rarely acidents happen because the crew elected to continue. Mishaps because of a rejected take-off are frequent however.

[Flight Safety]

How can you accurately judge V1 (go,no-go) with an airspeed disagreement?

The aircraft looks good, no landing gear collapse.

[TheWanderer]

How can you accurately judge V1 (go,no-go) with an airspeed disagreement?
As long as you are on ground, you might have a look at the groundspeed indication that comes from the IRS.
That schould give a rough estimate, with the reported wind of 020/10kt close enough.

[Checkboard]

... and there are three pitot tubes feeding three separate ASIs (the standby ASI uses the auxiliary pitot tube and alternate static port). You can have a democratic 2 to 1 vote. :ok:

"IAS DISAGREE" alert should have been visible on the Speed tape with > 5 knot for 5 seconds Captain / FO difference above 45 knots, although that would be easy to miss, and 5 seconds is quite-a-ways down the strip.

[quianor]

TheWanderer:

this answer seems silly to me... we can not "roughly estimate" a go/nogo decision, as we can not roughly estimate how close we are to V1.
During the take off roll, things happen very fast. Looking at the groudspeed given by IRS is not practicable, especially at high speed.

[Two's in]

Why then stop for an airspeed indication problem? You have to be go-minded, the aircraft almost always feels better in the air, except for engine and flight-control problems obviously.

The Birgenair and Aero Peru 757 accidents may slew your statistical analysis of what exactly "feels better in the air" means.

[Zeffy]

How can you accurately judge V1 (go,no-go) with an airspeed disagreement?

Accurately... instantly? -- a pretty tall order.

So if all engines are running, wouldn't it be wiser to continue from a short-ish runway?

[The Fat Controller]

If your pitot-static and air data computer systems are not functioning properly, as an ex-ppl, frequent passenger and current air traffic controller I would much rather the aircraft stayed on terra firma.

Looks like a similar situation as the recent Ryanair excursion at EGPK, lack of grip on the paved surfaces when most needed.

Glad that everybody walked away, may have been a completely different scenario if it had gotten airborne.

[taffazzi]

Another 737-8 with problems. Could this be becoming statistically relevant comparing with older versions of the 737s? There are plenty of -2-3-4-5-6-7 flying and lately mostly the -8 is making news.

taffazzi

[babemagnet]

Video:


Boeing rast über Startbahn hinaus - n-tv Videoportal (http://www.n-tv.de/mediathek/videos/panorama/Boeing-rast-ueber-Startbahn-hinaus-article662111.html)

[Navigator33]

Back when I did my TR on the 737 we aborted above 80 kts for exactly the same problem. This was during our final exam.
When we came to a complete stop my budy and I look at eachother as in "#### we screwed that one up now didn't we" Turns out the examiner was really happy with what we did.

Guess what will be in the back of my mind if this ever happens in real life.

[Dani]

Even if you do everything perfectly, you can overrun the concrete. Most pilots do forget that. Take-off calculations do not give you a perfect safety margin. Runway condition, brake performance, aerodynamical and thrust performance - there are many variables.

From far it looks like they did a good job, even in overrunning. It's a tough life out there - hopefully the facts and the chief pilots do agree with me.

Dani

[Takeoff53]

I do not fly the 73 thats the reason I'm asking the pros: For me a lot of flaps are hanging out for takeoff (my aircraft max flaps 22 for T/O). Is this a normal setting, based on the conditions this morning?

[Navigator33]

No these are the standard recall items in case of an aborted take-off.

-Flaps 40.

[Sallyann1234]

Aircraft not damaged, says the airline.

Those pictures suggest a pretty good inspection will be required!

[CaptSeeAreEmm]

EVACUATION

1 PARKING BRAKE. . . . . . . . . . . . . . . Set C

2 Speedbrake lever . . . . . . . . . . . . DOWN C

3 FLAP lever . . . . . . . . . . . . . . . . . . . . 40 F/O

4 Pressurization mode selector . . . . . MAN F/O

5 Outflow VALVE switch . . . . . . . . . Hold in OPEN until the outflow VALVE position indicates fully open F/O

6 If time allows:

Verify that the flaps are 40 before the
engine start levers are moved to CUTOFF. C

7 Engine start levers (both) . . . . . CUTOFF C

8 Advise the cabin to evacuate. C

9 Advise the tower. F/O

10 Engine and APU fire switches (all) . . . . Override and pull F/O

11 If an engine or APU fire warning occurs:
Illuminated fire switch . . . . . . . . . . Rotate to the stop
and hold for 1 second F/O

[Storminnorm]

Pretty good inspection, and lots of dry seat covers I think.

[BARKINGMAD]

Food for thought; Are the pax worse off by staying aboard (e g Airtours Manchester) or should we avoid the urge to kick them out on the slides 'cos someone might sue if we don't?

Evacuation almost always results in injuries to a significant proportion of the pax and has to be considered as a potential hazard as well as other risks.

I await the day when a RTO´d aircraft is informed by ATC and CC that white smoke is observed issuing from the engine with the faulty fire warning, which has just had a BCF bath from the extinguisher-throw them out to get carted off to hospital and we won´t be criticised?

It's an awkward call and that´s why we´re paid megabucks (allegedly!!) to consider scenarios where there may be no clear answer.

The AB pax are lucky they didn´t get kicked out into the snow to break legs and sprain ankles and shiver in the cold til the ambulance(s) arrive.

I throw this issue open for reasoned discussion and await the brickbats.:ugh:

[Love_joy]

The question of if an accurate go/No-Go call can be made with faulty equipment is entirely valid, I guess we'll have to wait for the report to discover what exactly they were being shown.

Overruns are a topic close to my heart, and this statement rang some bells; It is questionable if the stopway was completely deiced

Disappointingly, I have seen this regularly in Germany and it is quite probable that this scenario played a part in two incidents (that I can think of) where the reports are still outstanding.

Does anyone know if the runway is concrete or tarmac?
EDIT: Its tarmac, I've just had a look

[CaptSeeAreEmm]

Normally airspeed xcheck is carried out at 80 kt - and if the abort is carried out right away an overrun should not be likely.

[glad rag]

Lot of flap showing in that picture for take off???????

An earlier post stated

Runway is relatively short and stop margins with Airbus A320 with Conf 3 in the 30 to 60 meter region with WET RWY with medium weights and engine anti-ice on. TOGA thrust provides much better margins but it is still a short runway and many companies operating in and out have put restrictions as to who can be the pilot flying

Guess that will be the reason.

[captjns]

As stated by the Wanderer

As long as you are on ground, you might have a look at the groundspeed indication that comes from the IRS.

That schould give a rough estimate, with the reported wind of 020/10kt close enough.

First of all... good job by the crew for protecting life and limb:D.

Let's not forget the Stanby Airspeed Indicator. Saved my bacon on a steam driven aircraft about 10 years ago. We were also lucky because VMC conditions prevailed.

[WestWind1950]

good grief people, conditions were icy and no one got injured.... the pilot made the RIGHT decision!

Even FRA had tons of cancelations today because of conditions... and they are normally quite prepared, unlike a smaller regional field like Dortmund might be.

Two weeks ago I flew with AB from FRA to Teneriffa and it was a marvelous flight... no complaints from me.

Those of you who are perfect and never do a mistake, raise your hand. Hmmm... not many I see. :E

[Denti]

Acceleration on a near to unreduced take off (likely with the conditions in dtm today and the load of that aircraft) is pretty fast, so if you do the 80 call it can be quite a bit faster until the decision to abort is taken, wouldn't be surprised if you reach 130, 140 kts until first action is done.

Afaik you need special training to be able to operate out of DTM at air berlin, not every pilot is rated for that and those that are have to either operate frequently from there or renew it pretty often. The new delivered aircraft are all equipped with the short field performance kit and the aircraft involved is the second last one delivered, so probably around 500 hours old.

[stesoell]

Video: Cabin View

Winter in Deutschland - RTL.de (http://www.rtl.de/cms/information/rtlaktuell/artikel/news_inland/winter-in-deutschland.html?startid=201111&set_id=37593)

30sec from setting tkof thrust to rejection...

[ManaAdaSystem]

From a runway point of view-Go minded.
From a weather/type of malfunction point of view-Stop minded.

This is a good reminder that we are NOT guaranteed to stop under these conditions, even if we calculate everything correctly, and even if we perform the abort according to SOP. By saying this, I do not mean to imply that this crew did one thing or another.

The outcome could have been completely different if they had continued the take off with unsafe speed indications.

I'm just a bit curious about the amount of snow on top of the engines at the start of the take off. I did not expect to see that.

BTW, AFAIK, the evacuation check list is not a memory check list anymore.

[Checkboard]

It's obvious they deiced. You can see the deicing fluid shearing as the fluid on the fuselage leaves the aircraft during the first half of the take-off roll, and then reversing direction under the influence of the full reverse thrust. The snow is on top of the engines, because you don't use deicing fluid on engines, to avoid toxic contamination of the bleed air.

[ManaAdaSystem]

You avoid contamination by switching off the bleeds before deice, and last time I deiced they also used air to remove some of the snow on non critical surfaces.
It was just a bit unusual, that's all.

[Frosch]

Not enough we have to accept that at least one person in the cabin and one on the spotters balcony will be filming ANYTHING we do or say, no, now they go one step further:

YouTube - Ein kleiner Blick auf die Air Berlin, Flughafen Dortmund 03.01.10 (http://www.youtube.com/watch?v=wF35oLcbiVw)

No comment.

[TWOTBAGS]

The Crew did an outstanding job.! In positively CRAP conditions, Dark, slush, snow, shortish runway and long sector (= high weight).

Having just watched the RTL an bord video the crew did exactly as per SOP.

Probably full thrust take-off, abort, Passenger comments, “were braking”,

Full reverse, as evident by the blow back on to the window. STOP.

On completion, Cockpit announcement “Attention on Station”. (OM/ FSM p48)

Flight Crew (wenn handlungsfähig)
Anwendung Kommando
Alarmierung der Crew ATTENTION CREW ON STATION (2 times)
Beruhigen der Crew NORMAL OPERATION (2 times)
Evakuierung “EVACUATE, EVACUATE, EVACUATE”
Evakuierung mit
Angabe des
Evakuierungsweges EVACUATE ……. (left, right, forward) (3 times)


This is were assessment is made, and if there is no reason to you “DO NOT EVACUATE into a hostile environment”.

The NG has some rather interesting fun when heavy on a contaminated runway.

A few years back an AB –800 landing in TXL, meet all the performance requirements and factorization for landing in similar conditions, they overran by 100ft! We were #2 and had to divert to SXF.

Now think before you comment, would you really want to depart into the clag with “unreliable” airspeed and have to return in OVC 005 conditions.

NO NEITHER WOULD I.

End result, no injuries, no damage, crew did what they were supposed to.

[GearUp CheerUp]

glad rag

Lot of flap showing in that picture for take off???????

You only had to look back 4 posts previous to yours to see that selecting Flap 40 is an SOP on that aircraft in the event of an RTO.


Runway is relatively short and stop margins with Airbus A320 with Conf 3 in the 30 to 60 meter region with WET RWY with medium weights and engine anti-ice on. TOGA thrust provides much better margins but it is still a short runway and many companies operating in and out have put restrictions as to who can be the pilot flying

Guess that will be the reason.

Eh? what does A320 have to do with it? The aircraft in question was a boeing 737.

[Nightfire]

Flaps 40 on the 737 is an item on the evacuation checklist; the point is that passengers using the overwing emergency exits need to slide down the trailing edge of the wings. It has nothing to do with a takeoff-flap setting.

The mandatory callout "80 knots" - "checked" is not just an incapacitation call, but it also checks the correct airspeed indication. I haven't flown the 737 for several years now, but the AIRSPEED DISAGREE checklist (is that the correct title?) applies only after airborne (determine which indication is correct, if necessary with the performance inflight-tables).
during takeoff-run, there is no time for that. The non-normal briefing should include something like "After 80 knots, before V1, I will reject the takeoff only if the aircraft is unsafe for flying". Which was the case here.
If it had happened after V1, the situation would have been different (which is why V1 is usually reduced on a contaminated runway).

The final decision on weather or not to evacuate the aircraft after it has come to a stop usually lies with the commander. It depends on what AB's manual says (I don't work for them).
Another thing to bear in mind what some know-everything-guys didn't mention in their wisdom (one guy said in a previous post that "Air Berlin choses pilots according to fluency in German language over any flying abilities"), in this case, is the freezing weather.
If you evacuate the plane, not only will some people undoubtedly get injured. You will also have some 160+ passengers, many under shock, some others with special needs, some elderly, some small children, etc. - walking/sitting/lying around in the area, on a wet snowy surface. Waiting for the ambulances to arrive and taking care of the majority of people may easily take another twenty to thirty minutes. Maybe this factor is not yet deadly, but it's certainly a serious health-hazard.

An evacuation may still be necessary if the aircraft is on fire, but that was not the case. It seems that the Crew went through their checklist, and then decided to disembark the passengers in a safe manner. With both engines and the APU shut down, and most electrics unpowered, there was no reason to panic. All that had happened was a collapsed nosegear.

Therefore I believe it was a very good decision. :ok:

[Brookfield Abused]

On the German news, a pax from the accident made the statement and hand sign that the aircrafts body angle had started to pitch up and then down (he did not say whether he felt the aircraft had gone airborne) followed of course by the rejected take-off run. He also made no estimate to the speed at which the aircraft left the runway. He did mention when the aircraft came to rest, the engines were shutdown and the controlled evacuation was ordered.

[despegue]

In the end, job well done by the crew as nobody got injured. That is the benchmark.
I have had this situation before, where my speed indication (speed tape and ASI on a B733) went to zero after the 80kts. callout of the PNF. I called the failure checked PNF side ASI worked and gave controls to him. With 2 working speed indications, we climbed to do some trouble shooting, discussed the options (weather was bad) and returned to the field. I felt that the situation was not critical enough to perform a near V1 reject. It is a somewhat difficult failure to decide on actually and a good exercise for the sim.

In order for all speed indications to go blank, you need to have a failure of all pitot tubes, both ADC's and no ground-speed readout from the IRS.
Unlikely indeed, but I do know a crew which had this situation in reality, luckily in severe CAVOK with a B735. So it IS possible.

[sleepypilot]

very negatively impressed by the view of all that snow on the engines.
Nothing to do with the aborted TO, but I'm curious what the wing conditions were.
And yes, the engines are deiced.

[I Just Drive]

There but for the grace of God go I. Any one of us could have an IAS disagree at 100+kts on a dark and stormy, snowy night on a short runway. You go, you're wrong, you reject, you're wrong.

If its short and the weather is good, easy, you go.
If its long and its rubbish, easy, you stop.

Everything else is in the grey area in which you have to make a decision in 0.04 of a second. This poor sod made a decision and lost out by about 100m it looks like.

As long as the decision was early enough and the numbers were right then these guys should be fine.

B.T.W. is it Captains only rejects at Air Berlin?

[Super VC-10]

All that had happened was a collapsed nosegear.

There was no collapse of any landing gear. The aircraft came to rest on a downslope, that's all.

[All-Ex]

Here you can see a picture of the (almost?) intact nose gear:
Rutschpartie auf der Startbahn - Bildergalerie bei GMX (http://www.portal.gmx.net/de/themen/nachrichten/bildergalerien/9610572,page=3.0.html)

[alf5071h]

I Just Drive, you present an interesting view of take off procedures.
Surely, during take-off, the margins of the decision to go or stop are in procedures and are checked in the pre flight plan. The crew’s task is to execute the plan, not take ad hoc decisions which judge runway length, weather, and the nature of the failure during take off.

Pre flight planning determines V1.
Operational procedures should specify the crew actions in the event of failures. Conditional issues in the decision may be the nature of a failure and the airspeed e.g. engine failure always stop before V1, ASI malfunction only stop below 80kts. This simplifies the decision making and reduces risk of error.
An ASI failure or malfunction above 80kts might involve the same drill, - use the standby ASI.

Appropriately trained crews should be capable of continuing flight irrespective of the weather or runway length with a relatively minor failure.
Several posts in this thread suggest that crews / operators have not thought about this likely scenario, may not have specific guidance, or have practiced the procedure.
The problem is not about being wrong; it’s about thinking about safety issues in advance, planning, and acting according to the plan or evolving situation.

[I Just Drive]

alf5something,

Yes you are correct. V1 is calculated and it it is what it is.

There are many failures that are practised in the sim and there are rejects and there are continues.

However, its very much not as cut and dry as that.

This example is a classic if it is what it has currently been reported as.

At 80kts, both speed tapes are spot on in agreement.
At 120kts, there is a sudden and dramatic disgreement.
V1 = 125kts.

Edited to say that in general, an IAS disagree that is spotted, diagnosed and countered using the Sby ASI wouldn't be something i'd stop for at high speed.

(All numbers made up)

You can stop or you can go.

I was exaggerating the point that on a long runway with awful weather id be inclined to stop.

On a short runway with good weather id be inclined to go.

IN THE MOST SIMPLISTIC OF TERMS.

The rest is a judgement call. It gets made and then god willing, you only have to suffer trial by PPRUNE.

[LYKA]

sleepypilot very negatively impressed by the view of all that snow on the engines.
Nothing to do with the aborted TO, but I'm curious what the wing conditions were.
And yes, the engines are deiced.

Engine cowls aren't defined as critical surfaces in the Airbus FCOM. I wouldn't be too concerned over that aspect.

[sleepypilot]

LYKA, correct. Just reviewed the 777 AOM, and it's the same

"...a careful check of the fuselage, wings, tail, control surfaces, surface actuators, gaps between the airframe and control surfaces, engine nacelle inlets, landing gear, and gear doors must be made, and all ice, frost or snow must be removed from these areas prior to takeoff..."

Nevertheless I would, and will, always ask for a "clean" plane. That amount of snow did not look like the result of the precipitation between de/anti-icing treatment and takeoff.

[atakacs]

lot of flap showing in that picture for take off???????
You only had to look back 4 posts previous to yours to see that selecting Flap 40 is an SOP on that aircraft in the event of an RTO.

Flaps 40 on the 737 is an item on the evacuation checklist; the point is that passengers using the overwing emergency exits need to slide down the trailing edge of the wings. It has nothing to do with a takeoff-flap setting.

Don't you want to minimize lift at all cost in such a situation ? Or is flap 40 adding significant drag ? Or is it irrelevant ?!

[FCS Explorer]

it's actually irrelevant. during a RTO F40 get selected passing 60knots. by that time the aerodynamic effect is negligible.

[alf5071h]

I Just Drive, thanks for the clarification.
I see a problem with the residual choice of Go / Stop, at high speed (>80kts, but less than V1). My understanding of the safety statistics and industry recommendations is that for either a main ASI failure, or system disagreement, the Go option is the safer choice.
Many operators provide guidance for this via the 80 kt check and recommending the Go option above this speed (for an ASI failure / disagreement) , i.e. although physically possible to either go or stop, the go option is safer.
With good procedures and training, then the Go/Stop decision should be clear-cut, irrespective of the weather or runway conditions/length, the decision should not be left to our inclination. The Go/Stop decision is one of those few ‘canned decisions’ (but not prejudged) where after recognizing the situation – failure/speed, the choice is very easy.

The differing views expressed in the thread appear to relate to the operators guidance / procedures to be used for ASI failure (and if none, does this invoke the Capt’s judgment), or in the understanding of the relative risks leading to a Go choice, e.g. some people have suggested that flight with a single ASI is hazardous.

Although we do not have the details of this event, the thread discussion should be about the decision to depart the airfield if the runway conditions are marginal and not to consider the Go/Stop choice after a failure. The runway state / weather should not influence the Go/Stop decision for an ASI failure; they are part of the departure decision.
If the runway condition was a factor, then there could be similarities with recent landing accidents;- crews may not have good information about the runway state. Thus if the runway conditions are marginal, i.e reported ‘good’, but there is doubt, then crews should decide not to fly until the conditions improve or can be verified.
It’s better to make the decision in the planning phase than be faced with a poor option during take off.

[TheWanderer]

Don't you want to minimize lift at all cost in such a situation ? Or is flap 40 adding significant drag ? Or is it irrelevant ?!

Flaps 40 add drag and more important will assist in a possible evacuation situation.
Passengers using the overwing exits will find it significantly easier to slide down the wing using the flaps than jump down the wing from about 2 to 3 meters wing height.

[TheWanderer]

Some very interesting information from Boeing can be found at Boeings Aero Magazine #11 (http://www.boeing.com/commercial/aeromagazine/aero_11/takeoff_story.html).

[I love twins]

Just watched the cabin video and that looked like a filthy filthy night.

Well done to all of the crew on board. It's easy to sit and criticise in the warmth of your armchair, a different story altogether to have to do it.

[Me Myself]

I found the Dortmund runwy length :

Takeoff Distance6759 feet
2060 meters

Given their destination they couldn't have had a lot of margin given the weather.
Tough decision to make in that case. Me from my comfy armchair would have continued............ .
This said, the aircraft looks in pretty good shape meaning they couldn't have aborted at a very high speed.
I wouldn't bet my salary on breaking performances with this kind of weather. Looks good on the charts, different in real life.

[Max Angle]

This said, the aircraft looks in pretty good shape meaning they couldn't have aborted at a very high speed.

Well they didn't go off the end at high speed thats for sure however looking at the video (allegedly from the flight in question) I would say that the RTO must have been close to V1. With a short, contaminated runway the V1 would have been quite low and with TOGA power set it doesn't take long to get there.

[Checkboard]

My personal take-off brief runs something like:

"Config, Warning or Caution below 80 knots I will stop. Between 80 knots and V1 I will stop for Engine Fire, Failure, Loss of Directional control or if the aircraft is un-flyable .... "

If the "80 knots" call comes, and I am indicating something less I would stop.

So, if there is no "80 knots" call from the other side, I call the speed I see:
"85 knots!"

If there is no response I will stop, due suspected crew incapacitation. (I would consider this as a stop for a caution below 80 knots, even though the speed is a bit above - it's recognising the problem below 80 knots and acting within a reasonable limit which counts.)

If the speed call came back as "er ... I've got 70" I now have two choices:
Call stop immediately, which I would probably do if the response was quick enough.
Glance at the standby, and if it agrees with my ASI, call something like "100 knots - Continue!", which I would do if all this had taken us to 100 or so or faster.

[Brookfield Abused]

I think this is the video from this flight and rejected take off.

Very interesting to see when the engines spool up how the snow on top of the cowling is sucked in until the relative wind is fast enough to blow it backwards.

Watching the countdown clock - I see the reject seems to have started at 27 sec. after the pilot selected TOGA with the sound of the engines spooling down.

At the 45+ sec. mark (almost 20 sec. after the thrust levers were moved to Idle), the view shifts down and one does not see the reversers deployed yet.

Then near the 50 sec. mark the view is blocked by snow and slush - this is maybe when the reversers have been deployed at very low ground speeds.

A 25+ sec. take off run has accelerate to well past 80 kts, so a reject close to after V1 which must have been with reduced by at least 8-12 kts for wet/contaminated.
Reverse thrust selected too late and thus maybe even the Speed Brakes extended too late after the thrust levers were brought to Idle.

[Checkboard]

At the 45+ sec. mark (almost 20 sec. after the thrust levers were moved to Idle), the view shifts down and one does not see the reversers deployed yet.You can't see the reverser sleeves because of the angle.

Then near the 50 sec. mark the view is blocked by snow and slushThat isn't snow and slush. That is de-icing fluid (you can tell by the way the glycol shears). You can see it reverse flow around 40 seconds - indicating the reversers are deployed and producing reverse thrust. :rolleyes:

[threemiles]

Reversers? Relevance at all?
I would care about the brakes and the tires after an abort. They bring the aircraft to a stop.

[LBR]

The Crew did an outstanding job.! In positively CRAP conditions, Dark, slush, snow, shortish runway and long sector (= high weight).

What was so 'outstanding' about it?

Having just watched the RTL an bord video the crew did exactly as per SOP.

I probably watched a different video, didn't see or hear the cabin crew doing anything.
Just saw an aircraft aborting after approx. 27sec. after they started their takeoff run.
If it was indeed because of an ASI disagreement I would consider it as a wrong decision.
Those flying the 737 have been trained to cope with unreliable airspeed.
With fuel for DTM-LPA they could have landed at an airport with long rwy and VMC conditions.
As far as I know an ASI disagree is not on Boeings little list with reasons for aborting a takeoff at >80kts speeds.
Is it AB SOP maybe?

Lets wait for the official results of the investigation...

[TyroPicard]

LYKA wrote..
Engine cowls aren't defined as critical surfaces in the Airbus FCOM. I wouldn't be too concerned over that aspect.Except that it was a 737. Did you notice how much snow was sucked into the intake when T/O thrust was applied? I would never go flying with that much snow on the cowling.
Re that A320 FCOM - any lawyer would easily convince a judge that all surfaces must be clear of snow, frost and ice for takeoff - the "critical surfaces" bit being for information only. Further down the page it specifically mentions engine inlets and "inlet lips".... I reckon that snow could be classed as being on the inlet lip.

[CDRW]

LBR - are you serious!!!!!

"Those flying the 737 have been trained to cope with unreliable airspeed."

Flight with unreliable airspeed means just that - not a take off with unreliable airspeed!! Good grief!!

[Sciolistes]

Flight with unreliable airspeed means just that - not a take off with unreliable airspeed!! Good grief!!
The generic briefing is along the lines of aborting before V1 if the aircraft is unsafe or unable to fly. This incident has forced me to carefully re-think what unsafe and unable to fly really mean.

My training says that aborting in the high speed regime is a knife edge of safety with virtually no margin for error or inefficiency. My understanding from said training is that being unsafe to fly means that rejecting the t/o carries significantly less risk than flying. Being unable to fly means a reasonable probability of not being able to control the aircraft.

We know that unreliable airspeed indicators do not affect the controllability of the aircraft, but would probably make reasonable assessments of V1 unreliable. Then, in my opinion, flying would generally be preferable to stopping.

[BraceBrace]

@threemiles:

Ico contaminated runway takeoff calculations, there's the option to include use of reverse thrust. So better use it then...

[despegue]

Look guys, I had this kind of failure, after the 80kts callout and I continued.
They elected to stop. Both ways, nobody was injured and the plane reuseable. So job well done.
Accidents need to be analysed as a learning experience, not as a critisizing game.

Flying a commercial jet is not an exact science, although some of our collegues seem to think so. It is an art really and once you realise this, you begin to understand that for each situation, there are several options, each with the potential to be succesfull or disasterous. It is how we handle our chosen option which decides the outcome. (this does not mean we have to break our SOP's and Drills so that we can start inventing new "procedures" on the spot mind you)

[lederhosen]

It is dark and snowing. You have been rostered to fly a long flight from the shortest runway you regularly use. The aircraft accelerates slowly due to the weight and the condition of the runway. At the 80 callout you identify a discrepancy between the airspeed indicators. It takes a moment to cross check against the standby and realise what has happened.

You call stop, start the reject and select reverse, which is not very effective as the speed bleeds off. The runway is very slippery and despite max effort the nosewheel slides off the end of the runway. Not a nice scenario. At the end of the day nobody got hurt and the aircraft looks as though it will be back in the air after a good inspection.

I seem to remember a similar incident with BMIbaby at Birmingham, sometime in the last couple of years. I agree with Despegue. Nobody is perfect and with hindsight we can all ponder the other options. But things could have been a lot worse, think Air Florida.

[arthur05]

I didn't actully ever intend to post on this forum, I'd rather leave that to the experts but having read this posting I feel compelled to contrubute for the first and probably the last time.:*
I'm not a Pilot nor even cabin staff, my only link to the Aircraft industry was many years spent in the Research and Development Dept at Rolls Royce, but for the life of me I do not see what all this fuss is about. A fully trained Pilot made a decision based on the information he had at hand at the time. Nobody else on this forum, especally the armchair sim pilots knows what the aircrafts Pilot saw out of his windscreen. The plane stopped, passengers alighted , no injurys, no deaths, not even injured pride. The pilot made the correct decission :D end of story. when I fly I want this pilot who dosen't take unnessary chances at the pointy end and I'm sure all of his or her passengers feel the same.
Arthur

[lederhosen]

It seems that the initial investigation has ruled out a performance calculation error and is of the opinion that the aircraft should have have stopped on the runway. Two hypotheses are being investigated: the runway braking action was not as reported or the crew disarmed the autobrake during the RTO. The first is not hard to imagine given the snowfall and temperature. Manual braking in these conditions would not improve matters and has led to some off runway excursions in the past.

[Max Angle]

Hmm, should have stopped on runway for sure BUT this incident will probably highlight the fact that contaminated performance is at best a shot in the dark, an estimate of what might happen. Very little of this data is supported by flight testing in the actual conditions and it's only when you come to do a high speed reject on a contaminated runway that the limitations of the data, the runway reports and the tables become apparent. I am willing to bet that, despite the inbuilt safety margins, a large percentage of limiting, contaminated runway departures would result in an overrun in the event of a high speed RTO.

[safetypee]

Re. … contaminated performance is at best a shot in the dark, an estimate of what might happen.

Quotes from CS 25 AMC 1591, (the basis of calculating the performance), i.e. how the operation might be conducted – ‘Can we do this’ attitude.

Operators are expected to make careful and conservative judgments in selecting the appropriate performance data to use for operations on contaminated runways.
Due to the wide variation in possible conditions when operating on contaminated runways and the limitations inherent in representing the effects of these conditions analytically, it is not possible to produce performance data that will precisely correlate with each specific operation on a contaminated surface.

A further quote involving a ‘Should we be doing this’ attitude, similar in the old JAR OPS IEM, but no EU equivalent?

Operation on runways contaminated with water, slush, snow or ice implies uncertainties with regard to runway friction and contaminant drag and therefore to the achievable performance and control of the aeroplane during take-off, since the actual conditions may not completely match the assumptions on which the performance information is based. In the case of a contaminated runway, the first option for the commander is to wait until the runway is cleared. If this is impracticable, he may consider a take-off, provided that he has applied the applicable performance adjustments, and any further safety measures he considers justified under the prevailing conditions.

An adequate overall level of safety will only be maintained if operations in accordance with JAR-25 AMJ 25X1591 are limited to rare occasions. Where the frequency of such operations on contaminated runways is not limited to rare occasions, operators should provide additional measures ensuring an equivalent level of safety. Such measures could include special crew training, additional distance factoring and more restrictive wind limitations.

These types of operation are highly dependent on how the runway conditions are described and the decision makers operational mindset – “can we do this” or “should we be doing this”. Think about it.

[lederhosen]

I understand that the runway was reported as wet. It is perfectly conceivable that on line up in the dark it would not be possible to assess that the the stop end might be in a worse state than the beginning of the runway.

Incidentally they should have had additional margin as they were able to use both thrust reversers rather than the one allowed for in the performance calculation.

A fair question would be, is it sensible to plan Canaries flights off marginal runways, in the middle of winter, particularly when there are nearby alternatives?

[IFixPlanes]

It seems that the initial investigation has ruled out a performance calculation error and is of the opinion that the aircraft should have have stopped on the runway. Two hypotheses are being investigated: the runway braking action was not as reported or the crew disarmed the autobrake during the RTO. The first is not hard to imagine given the snowfall and temperature. Manual braking in these conditions would not improve matters and has led to some off runway excursions in the past.

In the preliminary Report (BFU file number 5X001-10) only states:
The take off was aborted at 120 knots due to different speed indication. The A/C overrun the end of runway.

[lederhosen]

Thanks for your input IFixPlanes but sources in Germany are reporting that Lothar Müller of the Bundesstelle für Flugunfalluntersuchungen (federal accident investigation) made these comments on Tuesday.

So in saying I am wrong, I think you may be jumping to conclusions based on partial evidence.

Incidentally do you think the abort started at 120 knots or that that was the highest speed reached after the RTO decision was made?

[IFixPlanes]

I only quote the initial notification at the preliminary report of the BFU (Aktenzeichen 5X001-10).
No assumption from my side. To calm you down i have removed the "no". ;)
BTW i am a mechanic not a pilot.

[lederhosen]

No problem and thanks for making the change. I think both sources add to the debate. The interesting bit for me as a 737 skipper is the go / no go decision making and what I can personally learn from it.

[safetypee]

120 kts appears rather high even for any overswing acceleration for a reject at V1; particularly high for a single ASI fail or miscompare. Any comments, or an approx V1 on the short runway (Re #80).
On what basis is only one reverse used in RTO performance, isn’t it all or nothing (Re #78).

[Brookfield Abused]

Ok so a reject "initiated" at 120 kts.
Brakes on speed was maybe 125kts?
But with a reduced V1, it may well be at this number or above?
Usually Field Limit ASD (calculated) will stop the aircraft so that the nose wheel is maybe just about to go off the pavement (a few feet prior)!
Next question is what sequence happened after the trust levers were closed to idle?
Were speed brakes manually deployed or extended after thrust lever/s selection?
Were thrust lever/s raised - if yes, when, how much thrust was selected?
IF the Pilot Flying forgot to perform the above sequence, were call-outs made by the PF? What reaction did that bring?
When were the thrust levers lowered?
Was braking performed by the auto-brakes, manually or a combination of?
If you know you be going off the runway - a BRACE BRACE would have been nice to hear!

[lederhosen]

Credit is allowed on wet runway for one reverser as per 737 QRH performance text. The logic is that you have one reverser on a twin if an engine fails before V1.

For Brookfield Abused the 737 has an auto speed brake system which operates when wheel spin up above 60kts, thrust levers idle and reverse selected. These conditions existed.

As I posted earlier the investigator is reported as saying that the performance calculation was OK and the aircraft should have stopped within the runway available.

[Tee Emm]

Looking at the groudspeed given by IRS is not practicable, especially at high speed.It should be normal procedure at the 80 knot IAS call by the PNF for both pilots to check the ground speed. In any case knowing the wind component the ground speed should be IAS plus or minus the HW or TW component. This is very handy if an ASI problem shows up later in the take off run. There is very little time to assess which airspeed indicator is playing up and experience has shown countless times that a high speed abort on a limiting length will invariably result in an overrun - particularly on a wet runway.

That is where an alert crew will switch to ground speed for lift off. Of course, the pilot has to have some idea what ground speed he needs to lift off safely. That is good airmanship. The 80 knot check in a Boeing is much more of an important safety check than many pilots realise. For instance, if during the take off run the PF does not hear or does not receive the call "80 Knots" from the PNF as the PF airspeed passes 80 knots, it is good airmanship for the PF to call out something like "90 knots my side". Because by the time he realises the other pilot has forgotten to call 80 knots - or for some reason the PNF has not yet reached 80 knots on his ASI, the PF may well have 90 knots or more. By calling his own airspeed after not receiving the expected call-out from the PNF, this gives early warning of a potential problem. But few operators have this policy.

Simulator training in this regard is vital, as it shows out the momentary confusion that will occur when conflicting airspeed indications occur during a take off roll. The secret is to be prepared. Well trained crews should be prepared even though the company SOP may have no mention of erroneous airspeed indication during take off. After all, company SOP cannot foresee every problem that can occur when flying and some responsibility must be borne by the captain to run his ship safely. It is no good falling back on an excuse that there is no SOP.

A couple of years back there was an erroneous airspeed incident to an A330 during take off. The company SOP required a 100 knot call by the PNF as an airspeed comparison check. The captain was unaware that an insect was affecting his ASI. The F/O was PF and as he passed 100 knots he expected a 100 knot call from the captain. It did not occur because the captain's ASI was under-reading significantly caused by the insect blocking his pitot tube and his ASI had not yet reached 100 knots.

The F/O said nothing, thinking the captain had probably been distracted by something and had forgotten to call 100 knots. When the captains ASI finally did reach 100 knots he called it. The surprised F/O then pointed out his ASI was close to V1 whereupon the captain belatedly realised there was an ASI problem - but which one? The captain took control and aborted the take off around V1. The RTO feature worked as advertised and the aircraft stopped safely. During the taxi back the tyres deflated and the brakes were very hot. All this could have been avoided if the F/O had called something like "110 knots my side" when he had not received the captains expected 100 knot call. In that case, if the captain decided to abort, then the speed would have been significantly lower with obvious greater safety margin plus less chance of hot brakes and fusible plus blow. Airmanship is a word that has long since departed from aviation lexicon. Some crews rely 100 percent on company SOP to cover all exigencies when this is patently not good airmanship..

[Avman]

a BRACE BRACE would have been nice to hear!

Maybe, but with a plane load of German tourists? Don't think it would have helped much. In any case, I'd say (from the video) that they slipped off at a very low speed. There was no apparent indication of anything other than a fairly smooth halt.

[Brookfield Abused]

BRACE BRACE BRACE call??
When these events happen, EVERYTHING is confiscated and reviewed by your company and the Authorities (in this case the LBA) from your briefing to the cabin crew, Tech-log handling and signing, Load Sheet notations/calculations, to your rest period and actions the night before. The best is the Voice Recorder. So when the CVR is combined with the FDR data, everyone who has access- knows what you briefed, any personal comments you made, non-SOP comments or actions, exclusions, etc. Then comes the FDR data which = actions by the pilots and there is no hiding errors.
So if you want to minimize your potential and professional liability - a BRACEx3 call (the pilots had enough time) would have made a very good impression in yet-to-be filled LBA Report which will be 20-30 pages long.
On Field Length Limited T/O's when wet, slippery with a combination of contaminated conditions exists (the worst in my mind and impossible to calculate an ASD), these performance calculations are just that - a computer model which is only a prediction of how a generic AC and crew will behave with standard (JAA) reaction times.
So if the calculated data was correct - then comes the crews reactions and the actual runway conditions. I assume DTM Airport Auth. will have done there BA tests right after the event.
The De-icing Operator will have been interviewed, fluids, hold-over times and his training checked.
Did the Crew accept maybe old and no longer accurate BA data, did they request a new RUN to be done?
Were they in GET HOME ITUS mode? Where they driven by an Airport Closure?
Back to the performance issue.....
In a Rejected Take Off (especially under these conditions) the pilots actions from thrust lever closed, manual speed brake extension together with max. manual/Auto braking, followed by reverser deployment (added decel. bonus) and max thrust spool-up- all must be done without the omission OF ANY ACTIONS or the calculated performance means nothing and for sure you will be doing what they did! With another 10-20 m's of skidding into the Approach Lights metal support frames there could have easily been a fuselage/wing fuel tank breach and fire (plenty of fuel to burn)!
So I come back to the spoiler deployment. Yes, when a reverser is selected the auto-speed brakes are activated and deploy. However, how many times in the sim have I seen people mix and mess these actions up. This comment thread started after watching the video clip from the pax sitting near Eng. 1. We cannot see what the ground and lift spoilers did/deployed when the reject was begun with the thrust levers being closed (reduction in engine sound), but it looks like the reversers MAY have been deployed too late (over 10 sec. after the reduction of the engine sound). Thus the idea that maybe the spoilers extended much later, perhaps not being raised manually right after the Thrust Levers were closed (is a Boeing recommendation).
As far as I know, these performance calculations are made with NO REV THRUST ANYWAYS.
Even if this is just a POSSIBLE sequence of events, it is worth while taking the time to remember just how important these RTO events are ESPECIALLY on this type of short runway with these extreme atmospheric and runway conditions.
Often I see people briefing WE ARE GO MINDED, meaning something like the unreliable airspeed AFTER 80 kts would be taken AIRBORNE with a call from the PIC - CONTINUE, etc! Not a bad briefing idea and execution in hindsight in this case!
So the CRV and FDR will reveal all.
So remember to ALWAYS CRASH LEGALLY and do your job right! The at least you are not to blame!

[safetypee]

Tee Emm, It should be normal procedure at the 80 knot IAS call by the PNF for both pilots to check the ground speed.
I disagree. Even with a pre flight calculation of the expected GS, the accuracy of the wind reports will routinely give a discrepancy. How large can it be, what would the procedure be for handling this error, is it the FMS or the ASI in error, etc, etc.
Pilots should not be faced with such tasks during take off.
Airmanship (company procedure) should establish the essential tasks during takeoff to be balanced by the risk of the operation.
The 80 kt call helps with this; it provides a speed cross check and in many aircraft excludes most systems from any subsequent Go/Stop decision making.
Commercial aircraft have dual or triple airspeed systems, three ASIs. The crew’s task for an ASI disagreement or failure above 80 kts should be simple – which of the three ASIs agree (not which one has failed), use the two systems in agreement to continue the take off.
Do not change or add complexity with more procedures; in doing so you might open other opportunities for error.

How many seconds does it take to read you second paragraph – the procedure words and actions (#86) – in that time how much have you accelerated, how far have you travelled down the runway?

[Jim Croche]

Brookfield
For info, the A320 doesn't have manual lift dumping on the ground during an RTO or landing. The system uses weight on the wheel(s) to give partial or full lift dump. This, in turn, triggers the autobrake to work. If not enough weight on wheels, no spoilers therefore no lift dump and no autobrake and pulling the speedbrake lever will not extend them!! What a lousy system and it's been implicated in numerous accidents and incidents (Garuda, TAM for example).

[A37575]

Airmanship (company procedure) should establish the essential task

You should not make the mistake of confusing airmanship with company SOP. Company SOP is primarily designed to cover litigation. Airmanship takes in the whole picture.

Having observed the erroneous airspeed indication scenario in the simulator literally hundreds of times, we have noticed immediate confusion when an airspeed problem arises during the take off run. With the aircraft accelerating at around 200 feet per second in the latter part of the take off run, there is little time to look at a standby ASI and then compare it with two other ASI's and then calculate which ASI is safer to use. This action would take several eye movements as each ASI is not necessarily adjacent to each other and both the dial scale and needle or drum reading needs to be assimilated. Count on at least five seconds of momentary uncertainty before action is taken.

Remember, it is a different story if the simulator training exercise has been pre-briefed and the crew are aware an airspeed problem during take off is part of the box ticking exercise. In a real life one doesn't glue one's eyes on all three ASI's all the way down the runway to lift-off.

In contrast, a rough idea of what the ground speed should be at say 80 knots or 100 knots ASI during the take off roll will give you a rough idea of rotate speed. Forget V1 by now, because that is IAS and things may be happening too fast for it to be meaningful, practically speaking.

Boeing allude to this when it advises "ground speed information is available from the FMC and on the instrument displays. These indications can be used as a cross check".

To keep this discussion in perspective just remember the Boeing 80 knot or AirBus 100 knot ASI check is for gross errors - not just a few knots. same with the ground speed check if used. Again as stated in the Boeing FCTM, conditions beyond control of the flight crew may preclude following a maneuver exactly. The maneuvers are not intended to replace good judgement and logic. Good logic suggests a knowledge of the expected ground speed during the mandatory ASI check on the take off roll.

[IFixPlanes]

Brookfield
For info, the A320 doesn't have manual lift dumping on the ground during an RTO or landing. The system uses weight on the wheel(s) to give partial or full lift dump. This, in turn, triggers the autobrake to work. If not enough weight on wheels, no spoilers therefore no lift dump and no autobrake and pulling the speedbrake lever will not extend them!! What a lousy system and it's been implicated in numerous accidents and incidents (Garuda, TAM for example).

Hi Jim, first make yourself sure what happened at TAM accident. ;)
The aircraft sensed WOW but with one trottle not at (or near) idle you have no ground spoilers actuation and therefore no autobrake.

[safetypee]

A37575 Re: You should not make the mistake of confusing airmanship with company SOP.
Agreed; I could have chosen better wording, perhaps ‘airmanship and stewardship’ (organisational management – safety management) to represent the joint individual and organisational responsibilities in risk assessment – perhaps tactical and strategic assessments respectively.

I do not like, or wish to encourage the concept that company SOP is primarily designed to cover litigation, even if true.
IMHO this encourages pilots to relinquish their responsibility for safety, restricts thinking, and might lead to reduced flexibility which is essential for both safety and profitable operation. Furthermore if operational management think this way, then they too might stop looking at safety because they feel that their responsibilities are covered – safety is good enough, the SOPs meet the rules, and if not followed – blame the pilot. This is a slippery slope.

I agree with your discussion on the problems of identifying a speed error (failure is easier to detect) and the aspects of training. However, it should be the tenor of training to improve skill in crosschecking airspeed in these situations – knowing where to look, what to compare, and why, which appear to be the primary issues not understood by many newer / inexperienced pilots. (Experience isn’t about time on type; it’s about knowing what to do, when, and why to do it).

Perhaps the Boeing ‘FMC’ cross check was introduced after an instrument related accident. Thus, by introducing a new check (if only as guidance – or as legal cover), the reaction, to an accident which should have been prevented by other means, has unwittingly added confusion (complexity) which is open to misuse / misinterpretation.

[CONF iture]

Space pig, Lederhosen was not mentioning the autobrake system but the automatic speed brakes (spoilers) deflection logic ...

[Kerosene Kraut]

CVR is said to be useless as it was not stopped and got written over.

[Denti]

Any source for that? The CVR usually stops with both engines cut off in the 737, however you can restart it manually. Recording time is of course 2 hours as the aircraft was only a few months old.

[Kerosene Kraut]

Source? Just rumours as this is a rumours forum.