Ryanair uses all the runway.
Derating, flex, reduced power or whatever they call it, for t/o has been the cause of many problems. Never liked it or been comfortable with it.
When we all began learning, on light a/c it was always full power that was available, that was used for t/o. Using anything less than available you would be foolish in the extreme and you would fail a check if reduced power was used. Quite rightly so.
The heavies I flew, noise was an issue. Standard noise abatement departures required the aircraft to be as high ASAP, V2 + 10 kts until 1500 agl. Max power available within limitations, was used. Easier to reduce power when convenient, than having to apply extra power, should it suddenly be needed. Normally too late then anyway.
Now we have got away from the basics again. All about money I am aware. "If they think safety is expensive, try having an accident". You only need one bad accident in an outfit and it can bring the whole lot down.
When we all began learning, on light a/c it was always full power that was available, that was used for t/o. Using anything less than available you would be foolish in the extreme and you would fail a check if reduced power was used. Quite rightly so.
The heavies I flew, noise was an issue. Standard noise abatement departures required the aircraft to be as high ASAP, V2 + 10 kts until 1500 agl. Max power available within limitations, was used. Easier to reduce power when convenient, than having to apply extra power, should it suddenly be needed. Normally too late then anyway.
Now we have got away from the basics again. All about money I am aware. "If they think safety is expensive, try having an accident". You only need one bad accident in an outfit and it can bring the whole lot down.
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I understand the Ryanair guys try to justify the actions of their colleagues. Without wishing the guys harm. This is clearly not the first time at Bristol. It is probably a systemic problem. In my view it should be investigated. It is quite clearly not correct according to the Boeing training manual.
then the climb was then quite sprightly
edited to make terms easy to follow
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It seems that the guys with smartphones may know a thing or two more than some apparent professionals here. Which is rather alarming. With one engine out theres no way they would have made it. As for why, some of you may not care, I'd be interested to know.
And yeh, people post videos of unusual things that happen to them on the internet. Deal with it. Should people only comment on that in which they have proper knowledge? Maybe. Then I hope to see a lot less from round here concerning politics, climate change, and the like.
And yeh, people post videos of unusual things that happen to them on the internet. Deal with it. Should people only comment on that in which they have proper knowledge? Maybe. Then I hope to see a lot less from round here concerning politics, climate change, and the like.
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IMHO seems like a wrong take off calculation / flaps setting...compare with the orange aircraft video and look at the height vs runway marks...don't tell me it's the same. Quite sure the FDM has it all.
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Thanks for an obnoxious answer. I was looking for an estimate of the stopping distance with RTO selected at maximum weight on a standard day, from V1.
I think that it is disappointing that so many professionals fail to recognise that this was not a normal take off. Then there is criticism of SLF's and plane spotters who know full well that an aircraft has to cross the threshold at a certain minimum height.
Forget complex performance, it's common sense.
This aircraft crossed the threshold of 09 at least 140' too low- according to Boeing.
I think that it is disappointing that so many professionals fail to recognise that this was not a normal take off. Then there is criticism of SLF's and plane spotters who know full well that an aircraft has to cross the threshold at a certain minimum height.
Forget complex performance, it's common sense.
This aircraft crossed the threshold of 09 at least 140' too low- according to Boeing.
I was looking for an estimate of the stopping distance with RTO selected at maximum weight on a standard day, from V1.
Define "heavy"! It's impossible to give a finite answer to your question because it depends on many factors such as actual weight, runway slope and surface, V1, flap setting etc.
Last edited by fireflybob; 12th Oct 2017 at 20:39.
We don’t know the ATOW.
We don’t know the derate(s).
We don’t know V1 & Vr.
We don’t know if they were using increased V2. (Bit short for that but...)
We don’t know whether this was “tight” for some reason or whether it was completely normal and expected.
In other words, complete speculation.
What we do know is that in normal airline ops, performance software optimises as much as it can and on this length of runway it normally ends up as a balanced field. Also remember that TODA can include clearway, which is beyond the end of the paved surface, so your 35’ will not necessarily be achieved at that point OEI (but it will by the end of the clearway).
We don’t know the derate(s).
We don’t know V1 & Vr.
We don’t know if they were using increased V2. (Bit short for that but...)
We don’t know whether this was “tight” for some reason or whether it was completely normal and expected.
In other words, complete speculation.
What we do know is that in normal airline ops, performance software optimises as much as it can and on this length of runway it normally ends up as a balanced field. Also remember that TODA can include clearway, which is beyond the end of the paved surface, so your 35’ will not necessarily be achieved at that point OEI (but it will by the end of the clearway).
"Mildly" Eccentric Stardriver
I could of course be wrong, but my guess is the aircraft was way beyond V1. Ergo, they are going to get airborne. Having accelerated past V1, there is speed in hand to quickly convert to height if needed, following an engine failure. Not standard, or clever, sure, but dangerous? I don't think so. Oh and to add, we only get a picture from a window, and don't know any facts.
Standing by to be shot down. Many years in retirement.
Last edited by Herod; 12th Oct 2017 at 21:29.
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What we do know is that in normal airline ops, performance software optimises as much as it can and on this length of runway it normally ends up as a balanced field. Also remember that TODA can include clearway, which is beyond the end of the paved surface, so your 35’ will not necessarily be achieved at that point OEI (but it will by the end of the clearway).
As per many preceding posts, we do know that OEI the average aircraft should make 35ft at the end of TORA/TODA/ASDA if field length limited, either naturally or by dint of flex. This assumes an engine fail at VEF, one second minimum recognition time with less than full thrust, then V1, then accelerate at 50% thrust to VR, rotate, and climb to 35ft at 50% thrust. The quoted figures of being at 150ft at the equivalent point having not lost an engine don't seem unreasonable.
Herod, check out the Delta DC10 crash at Chicago for the result of reducing speed in the climb after engine failure. Best angle of climb speed is close to V2+10, if you have achieved that nothing is gained by flying slower.
Last edited by Alex Whittingham; 12th Oct 2017 at 21:53.
I'm with the OP - if, for whatever reason, the aircraft's acceleration on the runway was such that, at V1, there was less remaining TORA available than the required stopping distance (no stopway at BRS), then something had gone seriously wrong.
Of course whether or not that was the case isn't something that can be reliably established from a YouTube video.
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If you are planning balanced field, as most Boeing stuff seems to do, you are assuming TODA=ASDA (or usually TORA=TODA=ASDA). There being no stopway at Bristol your second sentence falls away, it can't be both balanced field and have a clearway longer than ASDA.
As per many preceding posts, we do know that OEI the average aircraft should make 35ft at the end of TORA/TODA/ASDA. This assumes an engine fail at VEF, one second minimum recognition time with less than full thrust, then V1, then accelerate at 50% thrust to VR, rotate, and climb to 35ft at 50% thrust. The quoted figures of being at 150ft at the equivalent point having not lost an engine don't seem unreasonable.
As per many preceding posts, we do know that OEI the average aircraft should make 35ft at the end of TORA/TODA/ASDA. This assumes an engine fail at VEF, one second minimum recognition time with less than full thrust, then V1, then accelerate at 50% thrust to VR, rotate, and climb to 35ft at 50% thrust. The quoted figures of being at 150ft at the equivalent point having not lost an engine don't seem unreasonable.
If you are planning balanced field, as most Boeing stuff seems to do, you are assuming TODA=ASDA (or usually TORA=TODA=ASDA). There being no stopway at Bristol your second sentence falls away, it can't be both balanced field and take account of a clearway that makes TODA longer than ASDA.
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They might do, and if they do it will increase TOM. More clearway increases FLL TOM and reduces V1, more stopway increases FLL TOM and increases V1, but if the calculation assumes anything other than TODA=ASDA (or TODR=ASDR if you like) it isn't the balanced field solution. Moving away from balanced field optimises the FLL take-off mass at the expense of quick and easy solutions. In this case, if it wasn't a balanced field calculation you are right, there is no requirement to make 35ft at the end of the concrete OEI.
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They might do, and if they do it will increase TOM. More clearway increases FLL TOM and reduces V1, more stopway increases FLL TOM and reduces V1, but if the calculation assumes anything other than TODA=ASDA (or TODR=ASDR if you like) it isn't the balanced field solution. Moving away from balanced field optimises the FLL take-off mass at the expense of quick and easy solutions. In this case, if it wasn't a balanced field calculation you are right, there is no requirement to make 35ft at the end of the concrete OEI.
However they had two engines operating and during a normal takeoff the aircraft would be above 150' crossing the threshold of the runway. Also it is clear from the video that had there been an Engine failure 500' prior to the end of the runway both stopping or continuing would have been very doubtful. Nobody wants to give me a stopping distance from V1 but clearly a reject would have resulted in an over run. V1 cannot be less than Vmcg.
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If you don't know when they rotated relative to Vr, and at what rate they rotated, saying anything about "they wouldn't have made it" or "something was wrong" is presumptuous.
Balanced field takeoffs are eye-opening vs taking off on long runways when you see the actual rotation point.
If you time other takeoff rolls 35 seconds (+/-) is fairly typical.
Balanced field takeoffs are eye-opening vs taking off on long runways when you see the actual rotation point.
If you time other takeoff rolls 35 seconds (+/-) is fairly typical.
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The 35' requirement would have been in case of an engine failure at V1 at the end of any clearway.
7. TERPS CRITERIA VERSUS ONE-ENGINE-INOPERATIVE REQUIREMENTS.
a. Standard Instrument Departures (SID) or Departure Procedures (DP) based on TERPS or ICAO Procedures for Air Navigation Services—Aircraft Operations (PANS-OPS) are based on normal (all engines operating) operations. Thus, one-engine-inoperative obstacle clearance requirements and the all-engines-operating TERPS requirements are independent, and one engine-inoperative procedures do not need to meet TERPS requirements. Further, compliance with TERPS all-engines-operating climb gradient requirements does not necessarily assure that one-engine-inoperative obstacle clearance requirements are met. TERPS typically use specified all-engines-operating climb gradients to an altitude, rather than certificated one-engineinoperative airplane performance.
10. METHODS OF ANALYSIS. Sections 121.189, 135.379, and 135.398 require that the net takeoff flightpath clears all obstacles by either 35 feet vertically or 200 feet laterally inside the airport boundary, or 300 feet laterally outside the airport boundary.
(1) The most common procedure to maximize takeoff weight when significant obstacles are present along the normal departure route is to use a special one-engine-inoperative departure routing in the event of an engine failure on takeoff. If there is a separate one-engine-inoperative departure route, then the obstacles along this track are used to determine the maximum allowable takeoff weight for that runway.
17. MISSED APPROACHES, REJECTED LANDINGS, AND BALKED LANDINGS.
a. General.
(1) Parts 121 and 135 do not specifically require an obstacle clearance analysis for oneengine-inoperative missed approaches or rejected landings. While it is not necessary to perform such an analysis for each flight, dispatch, or landing weight limitation, it is appropriate to provide information to the flightcrews on the safest way to perform such a maneuver should it be required.
Last edited by underfire; 12th Oct 2017 at 23:53.