737 excessive rotation speed - a hard act to follow

[sheppey]

Recently, an incident came to light involving an Indonesian registered Boeing 737 that would astonish Pprune readers used to hairy events common to that part of the aviation world. Edited for brevity. The take off run started on a 10,000 ft length runway.

The crew were apparently unaware of a problem with the captain's ASI until the 80 knot call by the first officer who was PM. The captain elected to keep going. The F/O called V1 and VR from his own ASI which was working normally. The captain continued the take off roll despite his own ASI giving a significant erroneous reading.

Approaching the end of the 10,000 ft runway the captain's ASI read 80 knots and the captain was forced to rotate to avoid an over-run. The aircraft then flew normally. Investigation revealed the actual ground speed at rotation was 298 knots, exceeding the maximum tyre speed limitation by close to 100 knots. A hard act to follow.

[Qantas_A380]

298 Knots!!!! Must be a world record for a 737 take off.

I imagine that the aircraft would have required an extensive inspection of both landing gear assemblies (if the incident was indeed reported at the end of the flight!!). Did they return to base or continue on to original destination?

Are there any other dangers associated with exceeding maximum tyre speed other than burst tyres & landing gear issues?

[atakacs]

Geez... I'm really surprised that they did not burst all their tyres!

[fireflybob]

You can't beat having a few extra knots for the wife and kids....

[BOAC]

Why didn't he loop it?

[framer]

:p
Thanks BOAC.
Maybe the Captain had been reading up on 'improved climb' ?

[Qantas_A380]

At least climb performance with an engine out was going to be adequate!!

[Centaurus]

A reflection on CRM in that particular environment that the FO didn't seem to take over and complete the take off themself.

In some Asian cultures - and others - there is no way an F/O would ever take over from the captain who is regarded as a Deity. We have various acronyms to describe flight safety issues. CRM/TEM/CFIT for example. The latest is LOF or Loss of Face:D

[Ka8 Flyer]

Flap overspeed by at least 50 knots. Quite impressive safety margins...

[Qantas_A380]

No warnings on the 737 for exceeding max tyre speed?

Or disabled because of ASI disagree?

[ZFT]

Do you actually believe this?

I would wait until there is at least something more factual to back this up.

[framer]

I'd believe anything after some clown in SE Asia tried to get a 737 to land at a ridiculous speed ( may have been 200kts) about half way down the runway a few years back. The f/o was squawking a bit but didn't actually intervene. This seems mild by comparison.

[Paracab]

At what speed will the thing finally give in and start flying anyway?!! Short of having the stick pushed forward!

[FlyingStone]

No warnings on the 737 for exceeding max tyre speed?

Or disabled because of ASI disagree?

No warning, although it's quite easy to do it during Improved Climb and hot & high operations...

[DaveReidUK]

At what speed will the thing finally give in and start flying anyway?!! Short of having the stick pushed forward!That was my first thought, too.

Frankly, the whole thing sounds apochryphal. But if any can provide a link to the investigation report of what would surely have been classified as a serious incident, I'll stand corrected.

[de facto]

See,if it were airbus,the stick would have gone up by itself:p
Case of an incapable pilot(s) or pilot incapacitation?

[BOAC]

It is probably the World land speed record for a tricycle............

It certainly breaks Gary and George's record in the T5 Lighting at Coltishall all those years back.:)

[Mikehotel152]

298 knots on the runway? I'd have to see the report. Sounds unlikely.

[BOAC]

MH - remember this is PPrune.........you get what you pay for here

[RetiredF4]

And nobody is suggesting, that the human sensors in the cockpit should have noticed that those big markers on the side of the runway were passing along quite rapidly on this takeoff?

[EMIT]

Just do some arithmatic with your highschool knowledge.

S = Vo * t + 0.5 * a * t2 (that is t squared)

Normally a lightly loaded airliner needs about 30 seconds to accelerate to about 150 kts (I know, that performance is already on the optimistic side).
Assuming a constant acceleration for the rest of the run, it would need 60 seconds to accelerate to 300 kts (close enough to 298).

Runway length needed to reach 300 kts under those assumptions - 4.500 metres (about 15.000 feet).

Conversely, if you want to have 300 kts within 10.000 feet of runway, the acceleration must be 7.5 kts per second. That would be an awful acceleration for an airliner - it would have to be empty and then also would require full thrust (not any assumed temp thrust reduction).

Like many others, curious to see the factual report.

[RAT 5]

Guy must have been pushing like hell to stop it auto-rotating. I didn't know Boeing made wheelbarrows.

[booke23]

Surely assuming normal T/O trim being set, the thing would have flown off itself long before 298kts......unless as mentioned he was actually pushing the column.

I'm not so sure either.

[Superpilot]

I guess the 98kt tailwind also played its part? :hmm:. What was that??? Did anyone hear a quack?

[cosmo kramer]

A 737-800 at flaps 1 has a liftoff attitude of 8.5 degs at normal speed for comparison.

Even assuming the 298 kts are true, the thing will not "fly off" by itself with 0 deg pitch. It's not a C172. The wing needs to be rotated into the airstream to generate sufficient lift.

[Big Pistons Forever]

I wonder if this is just miss reporting and the speed was 198 not 298 ?

As for continuing the takeoff with an airspeed disagree, considering the registry of the airliner in question, I find that totally believable :rolleyes:

[RVF750]

Indeed. You wouldn't want to take off in an -800 with Flap 1 though would you? Normal for -700 but never had the laptop offer it in the -800 yet...

[Intruder]

BS!!!

HOW could a 737 accel to 298 KIAS without getting airborne, with gear down and flaps in a Takeoff position?!?

HOW could a 737 trimmed for normal takeoff stay on the runway to 288 KIAS?

198? Maybe.

208? Maybe.

298? NO WAY!!!

[cosmo kramer]

You wouldn't want to take off in an -800 with Flap 1 though would you? Normal for -700 but never had the laptop offer it in the -800 yet...
Flaps 1 is a normal take off setting for the 800. 90% of my takeoffs on the 800 are flaps 1. Sounds like your company is restricting flaps 1 takeoffs.

[Mad (Flt) Scientist]

298 kph maybe? That's about 160 knots.

[SR-22]

A similar event
http://youtu.be/21qZPaCRSQI

[RAT 5]

As for continuing the takeoff with an airspeed disagree, considering the registry of the airliner in question, I find that totally believable

BerganAir did, and look what happened.

[cosmo kramer]

Each to their own, depending on runway length I would continue...

Look what happened to AirBerlin when they tried to stop in Dortmund. After that incident (and AF447), my airline increased training in flight with unreliable airspeed. Not a big deal to take it in the air and deal with it, as long as you know basic pitch and thrust values.

[booke23]

A 737-800 at flaps 1 has a liftoff attitude of 8.5 degs at normal speed for comparison.

Even assuming the 298 kts are true, the thing will not "fly off" by itself with 0 deg pitch. It's not a C172. The wing needs to be rotated into the airstream to generate sufficient lift.

So it's actually possible to get to 298kts on the ground in a 737-800 in take off config without any forward control column input?

[Cough]

Just to prove how lunar this thread has become...What speed does oops! did the shuttle touchdown at?

[booke23]

Just to prove how lunar this thread has become...What speed does oops! did the shuttle touchdown at?

Final approach (starting at 7nm and 10,000ft) 290kts, reducing in the pre-flare/flare to 195-205kts at touchdown.

It really came down like a brick...they would typically aim to be in the overhead of the landing strip at 50,000 ft and fly a kind of circuit to a 10,000 7nm final.....about an 18 degree glide slope on final!

[john_tullamarine]

As no-one yet has cited any authoritative source for the story, it probably will sit better in Rumours and News until it acquires some basis for fact ...

[despegue]

After 80 kts. You continue the take-off run for an airspeed disagree on B737.
Remember that after 80'kts. You should be "GO-minded".

If reall all asi's are incorrect, you still have pitch and thrust values, basic stick and rudder.

[Superpilot]

I assume it was at Jakarta and therefore on a typical 30+ deg C day? with density altitude already way past 3,000ft?

Well, this is about as scientific as you're going to get but according to MSFS and using the very respected PMDG 738 model, I reached the end of the runway at 215 kts (medium loads and fuel). Therefore I'd say someone misread the interim "report" and needs to go to Spec Savers (you're as blind as a bandicoot in Aussie speak).

[Big Pistons Forever]

After 80 kts. You continue the take-off run for an airspeed disagree on B737.
Remember that after 80'kts. You should be "GO-minded".

If reall all asi's are incorrect, you still have pitch and thrust values, basic stick and rudder.

The airspeed disagree was at the 80 kt call so isn't the Boeing SOP to reject at this point ?

[cosmo kramer]

Boeing only mentions prior 80 (79.9) and after 80 (80.1). Exactly 80 knots is a grey area :E

[Jetjock330]

Mach .72 Rotate Captain!:D

[BOAC]

Having trouble following the travel of the thread about the a/c that reached orbital speed on take-off. Does anyone know where the kids have put it now?

[Superpilot]

Last I heard it was due to catch up with Voyager 1 anytime within the next 24 hours. Watch this space! ;)

http://planete.gaia.free.fr/images/im.astro/syst.sol/sys.sol/voyager.pioneer.JPG

[Centaurus]

Normally a lightly loaded airliner needs about 30 seconds to accelerate to about 150 kts (I know, that performance is already on the optimistic side).

I recall from many years ago, my company asked its crews ti time how long it took to get to 100 knots (nil wind) in a 737-200 at varying weights at ISA +10 sea level. About 50 take off's were measured. In all cases it was between 40-45 seconds and it turned out as quite a useful acceleration check. 30 seconds to reach 150 knots would require an afterburner and 737's don't come equipped with one of those.

[SOPS]

I Am going for thar idea that the speed was reported in KPH not MPH. I could be wrong, but I think the tyres would be disintegrating at 300 mph.

[atakacs]

Notwithstanding the tires disintegration issue I simply don't think that the 737 has anywhere near the necessary thrust to achieve 300 mph after 10000ft...

[Big Pistons Forever]

Are there any western airline pilots on this board who upon hearing " 80 kts " from the FO and looking at their ASI and seeing a number much smaller; would continue the tskeoff rather than immediately calling for the reject ?

[Chesty Morgan]

How do you know which one is accurate?

[de facto]

Open the window:p

[Pontius]

Are there any western airline pilots on this board who upon hearing " 80 kts " from the FO and looking at their ASI and seeing a number much smaller; would continue the tskeoff rather than immediately calling for the reject ?

Above 80 knots (which would be the case), I'm only stopping for fire, engine failure etc, so I'd be happy to continue. A check of the standby ASI to see whose instrument is reading correctly and then use that to take to the air. Once airborne a more detailed check to establish the problem (almost certainly an ADC fault), while flying pitch and power if there's any doubt as to whose ASI is correct. Of course, with RVSM considerations v ADC etc I'll almost certainly not be going anywhere but I don't believe it is a reason for a 'high speed' rejected take-off.

[Big Pistons Forever]

An 80 kt reject on a 10,000 foot runway is not a big deal. I don't understand why you would want to take an obviously broken airplane flying......

[factor-x]

I've had this happen to me, I had an "IAS disagree" message show up on my PFD right after I made the "80 knots" call out. I was flying a brand new 737 NG, by brand new I mean an NG with probably 3 or 4 months of continuous airline use.


Our manual says that past 80 knots we only reject a take off for Engine failure, fire, unsafe/unable to fly. And as the previous pilot mentioned you fly specific pitch and power settings, and continuously monitor your standby instrument.


Eventually the message disappeared, only to come back during approach phase. Upon touchdown both EEC's went to alternate mode. The plane was written up, we told maintenance and we where given another plane for the flight to another city. End of story.

[Pontius]

An 80 kt reject on a 10,000 foot runway is not a big deal. I don't understand why you would want to take an obviously broken airplane flying......

Not saying it would be a big deal, Big Pistons, but (a)SOPs are there for a reason (b)take-off is not the time to be deciding if you or the manufacturer know better (c)an 'obviously broken' ASI is not a big deal to be taking into the air....especially when you can almost guarantee it's going to be a button push to solve the snag. Remember, we're not talking about a single-source pitot-static instrument here but a multi-source air data computer. The ASI problem is solved by selecting a different ADC, simple as that.

[Oldaircrew]

"Our manual says that past 80 knots we only reject a take off for Engine failure, fire, unsafe/unable to fly. And as the previous pilot mentioned you fly specific pitch and power settings, and continuously monitor your standby instrument".

I think that you will find that most pilots would feel that erroneous ASI is considered as"unsafe" to fly. You would be an idiot to take an aeroplane into the sky with said problem. At 80(or 100 in an Airbus), the ability to stop is really not a problem and is by far the better option IMHO.

[Superpilot]

ASI problems are a big deal even if the drill is simple. Why take a problem up into the air only to return and land overweight or have to burn fuel tonnes of fuel? I would reject even at 110. Rejecting at that speed is a less bigger deal. Granted very soon after that it becomes a totally different ball game.

[fireflybob]

Are there not three airspeed indicators on most jets?

[Chesty Morgan]

ASI problems are a big deal even if the drill is simple. Why take a problem up into the air only to return and land overweight or have to burn fuel tonnes of fuel? I would reject even at 110. Rejecting at that speed is a less bigger deal. Granted very soon after that it becomes a totally different ball game.

Why risk a high speed RTO for a minor snag? There is plenty enough redundancy to safely fly with one ASI failed.

I recently had an ASI failure during the take off roll. I compared the other four ASIs and we continued. Once clean I turned around and reset the ASI CB which sorted out the problem. I'd have looked pretty stupid having either rejected at high speed or landed overweight wouldn't I?

Oldaircrew, I don't know your back ground but I think you'll find that most pilots would NOT reject for a single ASI failure as it isn't unsafe. I think you'll find most pilots will follow SOPs and the brief.

[Metro man]

80 kts is hardly high speed and not far in excess of what you could take a high speed exit at after landing. Given a 3000m runway I'd be stopping and probably would't even need the brake fans afterwards. Why continue accelerating when there is a problem and safe stop is not in doubt ?

Obviously closer to V1 you'd be GO minded and would need a very good reason to reject, even a hydraulic system failure wouldn't be enough reason to stop.

Just for info, Airbus use 100 kts.

[Oldaircrew]

Chesty,

I would beg to differ. At that point an RTO is a minor affair. To try and determine which ASI is incorrect at that point in the T/O is a bad idea. It may not be as cut and dried as a simple failure of one ASI. You could merely have a difference of opinion of 10-15kts. I don't remember the Boeing but the airbus(330/340) has a limit of + or -6kts on the ground.

I would personally rather stop and look a little silly than go, cock the identification of the problem up and look dead.

[Chesty Morgan]

I'd like to think you wouldn't die because of one erroneous ASI.

Metro Man, how do you know you're only doing 80kts? What if you're actually doing 100? What does your brief say?

[Centaurus]

I would personally rather stop and look a little silly than go, cock the identification of the problem up and look dead.

That is why it is prudent to check the ground speed during the take off if you have a suspicion that one of the ASI's is giving erroneous information. The Boeing FCTM mentions that. If all else fails, then rather than doing a high speed reject it is better for everyone concerned to continue the take off and rotate on the ground speed indication with wind adjustment of course. Then sort out the problem at your leisure in the air. This is where simulator practice comes into play.

[Oldaircrew]

Centaurus,

Once again I beg to differ. Whilst I agree that it is good airmanship to cross check GS and Airspeed, not everyone does it. Time is an issue here.

As both ASIs are dead until 30 kts in the bus, you have about 15 secs to determine if you have an issue with the ASI at the same time doing the T/O calls and engine instrument monitoring. 100 kts comes up in about 20-25 seconds from the application of Flex(once again I am using the bus as I do not remember Boeing at all).

I think it is a mistake to continue the T/O and take an unsafe aircraft into the air. I know that we have procedures to deal with unreliable airspeed but the need to identify the problem correctly makes it less risky to stop rather than go as far as I am concerned.

[cosmo kramer]

People, you forget that in real life, it will take you many seconds to realize that something is wrong. Just a few seconds brain processing, and you have 120+ knots. And if both captain and co-pilot airspeed indicators (unlikely) have failed, you have no idea of the actual speed. That could easily be the recipe for an overrun on a short runway (see AirBerlin in Dortmund).

Unreliable airspeed should be a minor problem for a proficient pilot. Definitely not "unsafe to fly" in my opinion. And apparently not in the opinion of Boeing either (no mention to reject for unreliable airspeed above 80).

[gerago]

Boys, another chance to blow and pontificate! The Indonesians are suckers for punishment.

Have you read this thread? http://www.pprune.org/rumours-news/535943-us-air-phl.html

BRE was right about it : [QUOTE]BRE

Join Date: Mar 2007
Location: Europe
Posts: 114
If this had been a Korean or French airline, the bashing would have covered 10 pages by now...
[QUOTE]

Only a just 4 of days and it has gone to four pages for this thread!

[Metro man]

Metro Man, how do you know you're only doing 80kts? What if you're actually doing 100? What does your brief say?

If the ASIs read differently then one of them will read 80 before the other, at this stage the speed call or lack of should indicate a discrepancy. When I'm PF I still check cockpit indications as I'm the one who makes the decision to reject.

Airbus use the
STOP STOP STOP GO GO GO

model to deal with failures as speed increases.

[Centaurus]

Airbus use the
STOP STOP STOP GO GO GO

model to deal with failures as speed increases.

What a marvelous idea. You can have the PNF making call-outs with ever increasing rising inflection of his voice during the take off run of STOP stop stop - Get ready to go - go Go Go ROTATE:ok::ok:

[Chesty Morgan]

If the ASIs read differently then one of them will read 80 before the other, at this stage the speed call or lack of should indicate a discrepancy. When I'm PF I still check cockpit indications as I'm the one who makes the decision to reject.

Airbus use the
STOP STOP STOP GO GO GO

model to deal with failures as speed increases.

Unless one of them stops working after 80...

[Metro man]

Obviously the model is a bit too difficult for some people, it simply means at low speed you should be more inclined to stop in the event of a problem and at higher speed you should be more inclined to continue..

For info, Airbus inhibit most warnings during the take off roll and only something serious such as a fire will appear.

What if all the ASIs stop working, the attitude instruments all disagree, the altimeters freeze up and you go IMC at 50ft, your diversion airfields all go below minimum, the other pilot has a heart attack and the radios fail.Then you would probably wish you had stopped while you were able to.

[cosmo kramer]

What if all the ASIs stop working, the attitude instruments all disagree, the altimeters freeze up and you go IMC at 50ft, your diversion airfields all go below minimum, the other pilot has a heart attack and the radios fail.Then you would probably wish you had stopped while you were able to.
Let's all stay in bed. Life is too dangerous! :}

[Superpilot]

Chesty, your example has the benefit of hindsight. If on the other hand you departed with a heavy plane and it was a blocked tube that you diagnosed, somehow I highly doubt you'd be happy to fly through the ITCZ on your way to South America. You'd be looking to land ASAP and not before dumping $100,000 worth of fuel and probably feeling silly due to that. I think there is an unjustified amount of attention being paid to go-mindedness. Don't get me wrong, I'm all for it and totally agree with the concept but considering the maths and theory clears you all the way up to V1, 10-20kts is sufficient for go-mindedness.

On top of all, consider that on an Airbus, the first time you make the ASI crosscheck is really the first you get to realise if there's a disagreement. What are we saying then that we would NEVER reject due to speed problems because by 100-110Kts its too late??? If we cannot stop from those kinds of speeds safely on 10,000ft of asphalt even when wet, something is wrong with our training, the aircraft or even the regulations which allow for performance criteria and runway design that cannot support RTOs from such speeds.

[Centaurus]

On top of all, consider that on an Airbus, the first time you make the ASI crosscheck is really the first you get to realise if there's a disagreement

That is why Boeing has a policy of the airspeed check at 80 knots rather than the 100 knots of Airbus. Better pick the problem early than later further down the runway.

A wise pilot will cross-check his ground speed reading with his ASI reading at 80 knots. This is nicely covered in the FCTM with the following: "A pitot system blocked by protective covers or foreign objects can result in no airspeed indication, or airspeed indications that vary between instruments. It is important that aircrews ensure airspeed indicators are functioning and reasonable at the 80 knot call-out. If the accuracy of either primary airspeed indication is in question, reference the standby airspeed indicator. Another source of information is the ground speed indication. Early recognition of a malfunction is important in making a sound go/stop decision.

It is most important and good airmanship that if the PM does not make the required call-out (eg 80 knots, V1 and VR) the PF should make it.

An example (happened in Australia) of where this could have prevented a high speed abort involved an A330 on take off. An insect blocked the captain's ASI tube resulting in a significantly under-reading ASI. The PF was the first officer. As the A330 passed 100 knots the PF received no call from the captain. He did not query this omission and continued the take off roll. Approaching V1 the captain called "100 knots" The first officer as PF realised only then at the late stage of the take off that something was drastically wrong.

The first officer queried the captain on his 100 knot call when the F/O ASI was showing close to V1. The captain decided to abort the take off and taking control performed a high speed reject. On returning to the tarmac to rectify the defect the tyres deflated due to excessive heating caused by the abort.

A simple "110 knots my side" by the first officer as PF would have alerted the captain to a problem with his own ASI. Better still, a comparison of ground speed versus IAS at an appropriate time early in the take off roll would also alerted the captain to the impending problem and prevented a late high speed abort with it's concomitant hazards.

Whether it is an 80 knot or 100 knot call depending on manufacturer philosophy, for many pilots it becomes a parrot like Ho Hum call. On many occasions the call is made late. Call it what you like but it boils down to complacency and poor airmanship.

[Chesty Morgan]

You'd be looking to land ASAP

Why would you need to land ASAP? Why couldn't you continue to destination?

[haughtney1]

FWIW, (777) I'd stop, there is no time to conclusively decide on the cause, it it therefore IMHO inherently unsafe and moreover unwise to continue....

[FFRATS]

Where is this report anyway....Bulldust I think..

On Airbus, at '100 knots' call you say 'checked', and if not correct and error a 'unsafe' margin you reject....simple.

The 100kt Speed selected by Airbus would have the same 'pilot recognition' time delay as other speeds on takeoff.

Why would you accept a primary ASI error then take-off :ugh:
Rotating or stopping of the wrong one at V1/Vr could be far worse then 100kts with some error.

The speed error between 100kts and normal weight V1's would be sufficient to stop in 95% cases. Other short RWY's=GO minded anyway...

FFRATS

[atakacs]

Was there ever a report on this one?!