737 excessive rotation speed - a hard act to follow
Gender Faculty Specialist
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?
Metro Man, how do you know you're only doing 80kts? What if you're actually doing 100? What does your brief say?
I would personally rather stop and look a little silly than go, cock the identification of the problem up and look dead.
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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.
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.
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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).
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).
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Boys, another chance to blow and pontificate! The Indonesians are suckers for punishment.
Have you read this thread? http://www.pprune.org/rumours-news/5...s-air-phl.html
BRE was right about it : [QUOTE]BRE
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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!
Have you read this thread? http://www.pprune.org/rumours-news/5...s-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!
Last edited by gerago; 24th Dec 2014 at 16:59.
Metro Man, how do you know you're only doing 80kts? What if you're actually doing 100? What does your brief say?
Airbus use the
STOP STOP STOP GO GO GO
model to deal with failures as speed increases.
Airbus use the
STOP STOP STOP GO GO GO
model to deal with failures as speed increases.
STOP STOP STOP GO GO GO
model to deal with failures as speed increases.
Gender Faculty Specialist
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.
Airbus use the
STOP STOP STOP GO GO GO
model to deal with failures as speed increases.
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.
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.
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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.
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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.
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.
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
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.
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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
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
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
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
