Ryanair uses all the runway. [Archive]

BARKINGMAD

11th Oct 2017, 21:05

5453, that was probably in the days before various beancounters' money-saving ideas all met together in a wonderful union of engine wear reduction SOPs.

It may be possible that derating PLUS temp assumed takeoff PLUS improved climb all combined to need the maximum concrete available.

I'm glad I retired before I was asked to lob these 3 together in one takeoff, far too many variables and reductions of safety margins.

Even with only 2 of them used IAW SOPs at Taba, my previous and last company managed to exceed the tyre speed limitations one summer season, due to an unforeseen shift in the crosswinds at the time.

It's only a matter of time before this constant pursuit of takeoff using idle thrust will end in tears, but the promoted beancounters will be far from the scene and the company by then.

BluSdUp

11th Oct 2017, 21:07

Hard to tell, but that looks textbook to me!

In general any delay at Vr and or slightly slow rotation rate on the -800 , and you end up with V2 plus 15 to 25 kts.

In the N-1 case after V1 but before Vr obviously this RWY is tight, and a prompt rotation at Vr and a steady V2 climb is essential.

I was out of there with a full aircraft , over 4 hrs flight and flaps 25 the other day. No margin except for bleeds off next. Worked like a charm!

The Old Lady will perform! Just make sure You do not let her down if Murphy pulls a trick around V1 and the next few seconds,,,,,

Happy Take Offs and Landings

parabellum

11th Oct 2017, 22:11

I think what that clip demonstrates is that we have been spoilt, much of the time the runways are more than long enough but sometimes they are only just long enough, Bristol as a fair example.

Doors to Automatic

11th Oct 2017, 22:36

I'm sorry but that does NOT look like a normal take-off. Normally one would expect rotation to occur at the latest inside the markings at the far end, but be firmly in the air by the 1000ft to go point. I have rarely witnessed anything tighter than that in the developed world! That was certainly not the case here.

kungfu panda

11th Oct 2017, 22:41

That was very close. To say otherwise is a little silly.

And that was with two engines...

Dan_Brown

11th Oct 2017, 23:15

I would suspect their brief would be: "........ call rotate when at Vr, or approaching the end of the RW, whichever is the sooner"

Sailvi767

11th Oct 2017, 23:25

Generally on a balanced field takeoff you should be able to achieve 35 feet at the end of the runway with a failure at V1. They clearly would not have made that. The question is did they get bad data, load the wrong data or rotate very slow. I have seen bad data more than I care to admit. A bit of cargo gets omitted or a incorrect temp is imputed ect.. Does Ryanair use a central load planning or does the crew do the weights?

kungfu panda

11th Oct 2017, 23:31

I think that Boeing's windshear procedure recommends that you rotate 2000 feet before the runway end even if you haven't achieved Vr. Waiting until the piano keys?

Capn Bloggs

11th Oct 2017, 23:43

Pucker valve clacking pretty loudly on that one.

megan

12th Oct 2017, 00:09

Same event? Doesn't to me, nevertheless seems close to this SLF.

fACX1DvwhpM

kungfu panda

12th Oct 2017, 00:10

Ignorant kids with their toy phones are suddenly experts on take-off performance regulation calculations, are they?

A load of twaddle.

I just showed it to my 7 year old. He knows that it was :mad: close.

Freeze frame it at 2.30 and at the beginning of the Piano keys the main gear is still on the ground.

I was overloaded out of Dhaka a few years ago and decided to do according to the windshear procedure, rotate prior to Vr, 2000' before the runway end. I thought that that was close. Now I see that 50% of posters think that this take off was normal. I realise that I shouldn't have concerned myself.

das Uber Soldat

12th Oct 2017, 00:12

If someone can explain to me how they would have made screen height OEI then I'll agree its twaddle. Until then, that looks close to me.

kungfu panda

12th Oct 2017, 00:20

Same event? Doesn't to me, nevertheless seems close to this SLF.

fACX1DvwhpM

Different event but seems to prove a systemic safety failure because it was still to close based on a balanced field with both engines operating.

You don't need any basic knowledge of performance, loading, ambient conditions, etc. It's obvious:rolleyes:.

underfire

12th Oct 2017, 00:49

If that ac was even 35 feet at end of runway....well...why?

Looks a bit more than flaps 25, but hard to tell.

JanetFlight

12th Oct 2017, 03:11

Dont get envious but Dynasty did it much better also with a 738 on a 2000 mt rwy :ok:

https://www.youtube.com/watch?v=21qZPaCRSQI

21qZPaCRSQI

Capt Fathom

12th Oct 2017, 05:42

Freeze frame it at 2.30 and at the beginning of the Piano keys the main gear is still on the ground

If you look at the wing shadow and the background landscape forward of the wing, it is clear the aircraft is rotating at the 1000ft markers and certainly airborne at the 500ft mark.

Depends on what you call 'tight'.

RAT 5

12th Oct 2017, 06:23

it is clear the aircraft is rotating at the 1000ft markers and certainly airborne at the 500ft mark.

On 2 engines I would have thought it would be normal to be airborne, wheels off, by 1000' on this short runway NOT just starting the process of aviating. If this was a normal profile then I wonder if either a V1 Stop or V1 cut & go would had been successful. If the numbers were correct this late unstick may have been caused by a late/too slow/too nose heavy trim. The 2 guys up front will be able to enlighten us, but..............
What about some B738 pilots who are BRS based chirping up. What do the everyday guys think?

RAT 5

12th Oct 2017, 06:27

There were times B732 from LTN RW26 when we were glad of the valley if an engine failed; or so we joked in the bar. But a TFS from RW26 B732 was a trust & faith takeoff sometimes. What it was not was anything less than full chat, and a very careful 180 on the turning circle.

SliabhLuachra

12th Oct 2017, 06:45

Clearly you haven't had a chance to see the memo O'Leary sent out to crews.

'We've realised that we're paying for the whole runway, so use the f*cking thing'

(PS Daily mail this is a joke)

RAT 5

12th Oct 2017, 07:24

I wonder, in the same vain, if he tries to claim 1/2 landing fees by making short turn-offs.

fireflybob

12th Oct 2017, 07:46

Reminds me of a colleague who used to fly Cambrian BAC 111s out of Leeds who told me the story that it always looked tight as they rotated there so they queried the figures with the performance department.

The performance department issued new figures which to their consternation showed higher regulated take off weights as apparently some stopway or clearway had not previously been taken account of!

There's much about performance we could mention. It would be interesting to know what the wind conditions were for this take off. Whilst headwinds are factored by 50% and tailwinds by 150%, "calm" is not factored so if you've planned for calm and have a small tailwind the effect will be significant especially when field length limited.

I think it was a Danair B727 at Luton that took some of the localiser area with them on take off. There was several factors:- 2/3 knot component tailwind but calm used for planning, some distance wasted on 180 line up, (no line up allowances in those days), thrust on centre engine was slightly miscalculated and rotation rate much too slow.

When I was doing the B737-200 course at Boeing in 1980 they showed us a very interesting video on the effect of incorrect rotation (rate/speed) on screen height. After the video had shown the instructor asked what we though of it. To a man we all answered "rotate early!". The effects of rotating a few knots early were insignificant but the effects of rotating a bit late were startling.

Also I think someone in this thread mentioned "prompt rotation". I'm not sure what the meaning of this phrase was but from memory on the B737-800 I recall the recommended rate of rotation by Boeing is 2.5 degrees per second.

gearlever

12th Oct 2017, 07:52

Also very interesting, 00:30

https://www.youtube.com/watch?v=Kle80KB_s3I

LTNman

12th Oct 2017, 07:56

The performance department issued new figures which to their consternation showed higher
I think it was a Danair B737 at Luton that took some of the localiser area with them on take off. There was several factors:- 2/3 knot tailwind but calm used for planning, 50 metres wasted on 180 line up, (no line up allowances in those days), thrust on centre engine was slightly miscalculated and rotation rate much too slow.

It was a Boeing 727 and it was only the valley at the end of the runway that saved the aircraft as the aircraft ended up flying below the runway elevation after taking out the approach lights and the localiser.

Accident report PDF link

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0ahUKEwiB4rjAzurWAhWGDxoKHS74AhMQFghNMAc&url=https%3A%2F%2Fassets.publishing.service.gov.uk%2Fmedia%2 F5422eae1ed915d1371000031%2F13-1975_G-BAEF.pdf&usg=AOvVaw3Gt_5p6eDRwQjVR1Npo2Cg

Dan_Brown

12th Oct 2017, 08:01

Reminds me of the "Bristol Cowboy" in the early 1980'S? They took out the approach lights on the opposite RW. Now if someone had filmed that, it would have been a frightening watch.

fireflybob

12th Oct 2017, 08:21

It was a Boeing 727 and it was only the valley at the end of the runway that saved the aircraft as the aircraft ended up flying below the runway elevation after taking out the approach lights and the localiser.

LTNman - I meant to type 727 - typo, will correct - thanks!

Mikehotel152

12th Oct 2017, 08:50

I suspect the performance calculations on the EFB were correctly completed; that the crew assumed the Boeing OPT would provide sufficient margins; and that the rotation was slightly after Vr was called. Swiss cheese.

Using the 'optimum' setting on that programme minimises pilot input/consideration of actual physical margins to the screen height, whereas the landing calculations always provide physical distances that one can compare with the available distance to the preferred exit or runway stop end.

On a lighter note, the video reminds me of base training, where every take off was a bum clenching 'experience'.

parkfell

12th Oct 2017, 10:32

All this pontification could be finally put to bed if the FDM information was ever revealed.
It does seem rather "tight".

There was an even closer shave at Aldergrove in the summer which ended up being investigated by the AAIB ~ special 2/2017. See October 2017 monthly bulletin.

Metro man

12th Oct 2017, 10:39

The Bristol Cowboy article from Flight International is available here, taking out the approach lights was the least of his problems.

https://www.flightglobal.com/pdfarchive/view/1980/1980%20-%203937.html

Jwscud

12th Oct 2017, 10:44

BRS to the canaries/southern Spain is a fairly common route and a full 738 with 13t of fuel is pretty limited. Pretty much all Flap 25 takeoffs very close to TOPL and you’re right, there isn’t much runway available on rotation. Pulled that with a slightly late or slow rotation and it looks worse than it is.

Don’t forget that the slope on the departure end of 27 is quite significant, making for a worse visual picture than on a billiard table flat airfield.

The Ancient Geek

12th Oct 2017, 11:40

The runway at BRS was extended a few years ago by diverting the A38, there is no way of extending it more because it is on the top of a hill and the ground falls off at both ends.
There was a proposal to move it to Filton but the good idea was crushed by howls of protest from local residents.

BluSdUp

12th Oct 2017, 11:47

I am looking forward to the time when 7 years old and 13 yrs old tell me if I am good to go or not.
Until then I stick with what Boeing has tested and tipple check and calculate the
worst case at the time for No Go.
There is no margin except for the built in regulatory and tested.
Something I am quite happy with.

I have taken the 737-800 to the limit may times as per SOP and Manual but never past.
It does perform, with standard margin!
And it will in the N-1 case after V1 at BRS!
Providing YOU perform!
Rather simple stuff , relay.
Lots of rudder until Vr and a rotation rate of no less then 2.5 per second and a V2 climb which gives anything from 400 to 700 feet per minute.
NOT the two engine 2500feet per minute AND acceleration towards V2 plus 15 to 25 kts you are used to!
Not saying the CVR would be something children should listen to uncensored, but it is perfectly safe.
3000 meters are arguably safer , then again we manage to mess that up on occasions , dont we!!
Intersection takeoff with massive Flex or de-rate is the standard , is it not.

double_barrel

12th Oct 2017, 12:17

OK, as one of the children with a phone, am I hearing here that takeoff configuration is commonly setup to use every inch of available runway ? That takeoff looks like it allowed for less than 1% margin. I confess that I find that surprising. Wouldn't a soft tyre, an ingested sparrow or even an unexpected squall of wind up the chuff have a bigger effect on take-off distance than that? Or is there time and information to allow you to detect that you are not precisely on the expected speed-distance trajectory and give it a bit more wellie ?

sleeper

12th Oct 2017, 12:27

Making fun of the I-phone passengers is rather foolish. The video shows that when the runway end flashes by the aircraft has just finished rotating and is barely airborne. Whatever the reason this is way to late/low.
It is very strange to see the apparently professionals attacking the slf's and claiming that all was ok. It wasn't.

wiggy

12th Oct 2017, 12:29

I hate seeing colleagues (albeit in another company) being strung up by virtue of mobile phone evidence...

captain F

it is clear the aircraft is rotating at the 1000ft markers and certainly airborne at the 500ft mark.

Agreed, indeed probably before then..hard to tell because of the image quaity but if you use the leading edge wing route/runway edge sightline as datum it looks to me as if rotation has started by at least 1500' to go i.e. looks like there's evidence of pitching as they cross the TDZ marker 500' in/downwind from the main TDZ marking at the upwind end of the runway.

Whether the rotation was slow or not is up to the 737 guys to judge but I'm not sure we can judge off that video. As for height over the runway end.. we all know about possible lenses and forshortening etc, surely that has to be a don't know?.......

I've seen enough legit heavy (i.e. right up at RTOW) takeoffs out of hot and high places on a heavy twin to know how close it can look...mostly at night so thankfully I've yet to make youthingy or similar.

underfire

12th Oct 2017, 12:49

Also very interesting, 00:30
yes gear lever, seen that here before when it happened, no flaps

megan

12th Oct 2017, 13:24

AAIB bulletin (page 3) with the first report being a 738 21 July 2017 taking out the lights at Belfast due a thrust setting which was significantly below that required for the conditions of the day.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/650139/AAIB_Bulletin_10-2017.pdf

wingview

12th Oct 2017, 15:06

Also very interesting, 00:30

yes gear lever, seen that here before when it happened, no flaps

They had at least flap 1.

Back on topic:
To me this looks like an uncomfortable take off... :)

172_driver

12th Oct 2017, 15:44

The OPT does provide detailed margins in the Acc-Stop scenario, i.e. how many meters remaining if you must stop. The Acc-Go scenario is a bit more complicated, but IIRC it'll tell you the limiting factor (field length or obstacle normally). How many inches will fit under your boots is a guess only.

Apologies to those who do use these numbers as a reference, but my experience says those numbers are never looked at, let alone acted upon, in this particular airline. Whatever the computer says, goes.

I understand it wouldn't change things in this particular take-off as full thrust was likely already selected, but it's worth thinking about.

FullWings

12th Oct 2017, 16:05

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).

kungfu panda

12th Oct 2017, 16:36

What is the stopping distance from V1 of a heavy 737-800 with RTO?

kungfu panda

12th Oct 2017, 17:04

I believe that the Boeing training manual states that with both engines operating and a normal take off performed the aircraft should be at a minimum height of 150' above the runway end. Check "Go/Stop decision near V1".

Dan_Brown

12th Oct 2017, 17:07

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.

kungfu panda

12th Oct 2017, 17:18

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.

Sidestick_n_Rudder

12th Oct 2017, 18:05

Has anyone mentioned incorrect performance calculation/input yet?

rog747

12th Oct 2017, 18:23

It's a runway 27 departure, MLG couldn't have been that far off the ground on the piano keys, if not still on it.

Refer to this picture and tell me how much room for error there is.

http://puu.sh/xW1IY/1f1409f272.jpg

Acceptable margins for a derated takeoff? Not for me.

great plan - on the video Vr began over the 'big' TD zone marker and the mains were off just after the 'small' TDZ just before the end piano keys - height at the end of the runway was not very much - but hard to say as
then the climb was then quite sprightly

edited to make terms easy to follow

neila83

12th Oct 2017, 20:05

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.

Money first

12th Oct 2017, 20:05

Has anyone mentioned incorrect performance calculation/input yet?
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.

fireflybob

12th Oct 2017, 20:11

What is the stopping distance from V1 of a heavy 737-800 with RTO?

How long is a piece of string?

kungfu panda

12th Oct 2017, 20:23

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.:ugh:

Forget complex performance, it's common sense.

This aircraft crossed the threshold of 09 at least 140' too low- according to Boeing.

fireflybob

12th Oct 2017, 20:27

I was looking for an estimate of the stopping distance with RTO selected at maximum weight on a standard day, from V1.

Now you've added on a standard day - at sea level or 5,000 feet?

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.

fireflybob

12th Oct 2017, 20:30

Herod

12th Oct 2017, 20:48

What is the stopping distance from V1 of a heavy 737-800 with RTO?

Irrelevant.

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.

Alex Whittingham

12th Oct 2017, 21:31

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).

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.

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.

DaveReidUK

12th Oct 2017, 21:42

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.

Or, to put it another way, it's perfectly possible to give an answer if those variables are known. :O

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.

kungfu panda

12th Oct 2017, 21:44

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.

Alex. That 150 feet is a quote from the Boeing training manual. I am sorry that I have no way to post a link to it.

fireflybob

12th Oct 2017, 22:11

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.

Surely said company uses all airport data such as TODA etc to arrive at the max possible take off weight?

Alex Whittingham

12th Oct 2017, 22:34

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.

kungfu panda

12th Oct 2017, 22:51

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.

True and it probably wasn't a balanced field calculation because most companies use Boeing onboard performance tools now to calculate performance (I presume RYR used something similar). The Calculations they make use both clearway and stopway. The 35' requirement would have been in case of an engine failure at V1 at the end of any clearway.

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.

misd-agin

12th Oct 2017, 23:01

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.

underfire

12th Oct 2017, 23:19

The 35' requirement would have been in case of an engine failure at V1 at the end of any clearway.

Sorry, but not correct. 35 feet minumum is typical screen height for all DEP, and there is no criteria for EO, thus EO must meet the minimum. (with wet pavement the clearance is 15 feet)

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.

jack11111

12th Oct 2017, 23:19

Regarding camera point-of-view, Focal length of lens, angle of reference from ground...Are you going to believe me or your lying eyes. T'was tight.
.

Right Way Up

12th Oct 2017, 23:29

You can market it any way you want however from start of rotation to end of runway is 5 seconds. Three seconds rotating till airborne (10 degrees pitch ish) then airborne for the 2 seconds before end runway. Whichever way you look at it that’s not cool!

Musician

12th Oct 2017, 23:32

If my physics is correct, the formula for constant power from standstill is v=3/2*d/t, plug in d=2000m runway and t=38 seconds and we get a threshold speed of 153.5kt, plus/minus measuring error. That's the theory, anyway.

See later posts for criticism.

parabellum

12th Oct 2017, 23:32

I think that it is disappointing that so many professionals fail to recognise that this was not a normal take off.

Cannot understand why so many posters here are prepared to accept, as prima facie evidence, pictures from a hand held smart phone taken by a passenger, through a side window, without any hard evidence to back up their highly speculative conclusion, hope they are never in a jury, anywhere. Personally I seriously doubt the professional status claimed by these posters, as well as doubting their exposure to limiting, but totally legal, conditions.

underfire

12th Oct 2017, 23:34

ASD
Sum of the distances necessary to:
Accelerate the airplane with all engines operating to V1 (assumes that first stopping actions are taken at V1)
With all engines still operating come to a full stop
Plus an additional distance equivalent to 2 seconds at constant V1 speed

kungfu panda

12th Oct 2017, 23:52

Cannot understand why so many posters here are prepared to accept, as prima facie evidence, pictures from a hand held smart phone taken by a passenger, through a side window, without any hard evidence to back up their highly speculative conclusion, hope they are never in a jury, anywhere. Personally I seriously doubt the professional status claimed by these posters, as well as doubting their exposure to limiting, but totally legal, conditions.

You clearly didn't pass your performance 'A'...Mate.

seanbean

13th Oct 2017, 00:01

...and when a thread runs to 5 pages, you just get the feeling something ain't right!

parabellum

13th Oct 2017, 02:23

neila83

13th Oct 2017, 06:05

And in any of those places, a takeoff like this with all engines running would be a concern. As I'm sure you know. It's quite basic, if an engine had failed at V1 would they have made it? Nom

One thing I know, if this video had been taken on a plane in Indonesia no-one would be saying nothing to see here.

Capt Fathom

13th Oct 2017, 06:28

It's quite basic, if an engine had failed at V1 would they have made it?
There's no guarantee!

You do the performance calc's, cross check them with your offsider and away you go.
If you both make the same error in the calc's and then have an engine fail right at V1, you've having a crap day indeed!

You can't second guess everything. You'll never get airborne.

RAT 5

13th Oct 2017, 06:48

Based on nothing more than an amateur filming a take off from a passenger seat through a passenger window with a smart phone!

That would include the smart phone video taken out of the window of the B737 going off the end of Thessaloniki on landing, then. :)

You can market it any way you want however from start of rotation to end of runway is 5 seconds. Three seconds rotating till airborne (10 degrees pitch ish) then airborne for the 2 seconds before end runway. Whichever way you look at it that’s not cool!

I'll reserve judgment due to lack of facts about the takeoff performance calculation, but the above is true. The photo is referenced ground markings and they do not lie. The numbers might well have been correct, but the rotation technique not. If PF was fixated on the runway, and also PM, who then forgot to call "V1" or "Rotate" it could be that no-one was looking the ASI. PF saw the runway end closer than ideal, glanced inside, said WTF and rotated. It was not a 'haul off' the runway, but still a normal rotation suggesting no panic. But the CVR would have been interesting in those few seconds, and perhaps during a discussion once in crz.
Reference my earlier point about monitoring; I watched nearly every F/O, when PF, on CAVOK calm days, just fixated on the runway with blinkers and never once glancing around. It was if they had no idea what else was going on, anywhere, other than the tarmac rushing by. I expect there will be divergent opinions about that so let's not start a topic drift; I just throw it out there as to why there might have been a late rotation, because that seems to be the case.
There was one poster who was concerned about derate, assumed temp, and improved climb all together. Is that possible? I thought improved climb required full umph, or did I misunderstood the comments? I doubt improved climb was in play here, as excess runway is required, and I doubt 2011m gives any excess.

wiggy

13th Oct 2017, 07:04

Parabellum

Try Johannesburg, (14000'), on a summers afternoon heading off on a ten hour sector, or Singapore, (13150'), any evening, heading to Europe only a few kilos below the limit for the conditions, both in a B747-400, believe me, runway ahead never disappeared so fast.

Agreed, and before anyone goes "ah yes but that is a four holer" I'll add NBO at RTOW on a heavy twin using improved climb to that list....the runway end looks to be getting darned close after V1 but before rotate...I have no idea what that looks like down the back because I am generally looking forward.

As for the video that started all this..As for the long take off claim..... Looking at the RHS window frame and the horizon I still think rotation started at or before 1500 feet to go...as for the rate, pitch attitude, and height over the end of the clearway I'd suggest the only objective arbiter is the FDR.

As for the general issue of videos such as this.., OK, the "producer" may have feel he or she has made an interesting observation,..OK, "air" it, for comment such as we have had, but absolutely no attempt has been made to redact the flight number/destination, the date is probably genuine, and if you look at his narrative he/she also grumbles about the flight ending in a hard landing....frankly some of these videos are starting to look less like an attempt to highlight something of interest and more like the work of somebody who gets satisfaction out of shouting "sir, sir" and who also twitches the curtains in their spare time.

EMIT

13th Oct 2017, 07:32

Quote (RAT5)
There was one poster who was concerned about derate, assumed temp, and improved climb all together. Is that possible? I thought improved climb required full umph, or did I misunderstood the comments? I doubt improved climb was in play here, as excess runway is required, and I doubt 2011m gives any excess.[/UNQUOTE]

Yeah Rat, in days of old, improved climb was only used with full thrust, to improve one engine out climb performance by using excess available runway length to accelerate to a higher Vr, and thus to a higher V2.

Today, the bean counters have invented the method to use excess runway length for a greater reduction of thrust, so that takeoff performance only JUST satisfies regulations.

As far as derate plus assumed temperature is concerned, that sounds more frightening than it is: if the situation calls for e.g. 85 percent N1, that could be achieved with e.g. Derate 2 at 35 degrees assumed, or Derate 1 at 48 degrees assumed, but e.g. Full rated at maximum assumed might for instance not be below 87 percent N1. So, in all cases, used thrust would be at least the same.
Biggest consequence of a derate would be subsequent automatic use of derated Climb thrust after thrust reduction point.

wiggy

13th Oct 2017, 08:07

parkfell

13th Oct 2017, 08:09

No doubt the jungle drums have by now reached the AAIB.

If they are in anyway concerned, an investigation will begin. Should this launch be classified as "abnormal", a published report will appear in the fullest of time.

RAT 5

13th Oct 2017, 08:19

No doubt the jungle drums have by now reached the AAIB.

Some of the similar scenarios mentioned, including the Canadian airbus in BFS, was it, caused ATC to notify the powers that be, as they were mighty concerned. What did ATC see on this occasion? Did they also think it was 'normal procedure and non-event'.?

Dan_Brown

13th Oct 2017, 08:25

+1 to the above

Within the last year or two to improve payload we have started routinely using reduced thrust ( if circumstances allow) and improved climb and if that wasn't enough also aft C of G performance if possible. That really does remove most of the fat and hidden margins people were used to in the "olden days". As EMIT says the figures are designed to just satisfy regulations...and guess what, whilst legit it can certainly look "close".....

Excuse me if i seem a bit slow, as i am a simple person.

How are you able to improve payload and performance using reduced power? This is the way I have read the beginning of your post.

I am aware things have moved on somewhat since I was involved. But that advanced?

DaveReidUK

13th Oct 2017, 08:41

If my physics is correct, the formula for constant acceleration from zero is v=3/2*d/t, plug in d=2000m runway and t=38 seconds and we get a threshold speed of 153.5kt, plus/minus measuring error.

Your physics is fine, but it doesn't apply here - acceleration isn't a constant, for a start.

wiggy

13th Oct 2017, 09:10

How are you able to improve payload and performance using reduced power?

Very very badly worded to the point of being wrong on my part :\ and since you rightly picked me up on I'll offer the following but you probably know this already.

Say I need to lift XXX tones..If I use some reduced thrust and normal climb I'll lift off Y metres down the runway...if I plan to lift off at Y plus a bit down the runway and use improved climb to meet the performance criteria I can perhaps carry the same payload and use a larger reduction in power ( power by the hour costs, etc now coming into play) ...or carry a bigger payload with the same power reduction.., or something between the two, or really haul the post with full power and improved climb ...etc etc...... (and if you'll excuse me I'll stop digging now).

Whatever the physics as a result you very much do end up further down the runway at rotate (and a bigger V1/Vr split) than in days of yore. On our Triple Operation we didn't used to see a V1/Vr split very often.....nowadays, except, at very light weights, it quite common to see a 10 knot or more split due to the higher Vr..

I've probably fouled up the above explanation but I certainly second the comment made previously that the bean counters love improved climb and other gems such as aft C of G for payload/engine cost reasons..but it can remove some of the "fat" we were used to seeing out of the window..

Musician

13th Oct 2017, 09:36

Your physics is fine, but it doesn't apply here - acceleration isn't a constant, for a start.
Yes, I'm aware of that: engines need to spin up, drag increases with velocity and when the aircraft rotates. The nice thing is that any nonlinearities in acceleration make the final velocity (ground speed!) be higher than 153.5 kt -- constant acceleration is the "most efficient" way to cover the distance and ends up with the lowest final speed of all possibilities (unless deceleration is involved). Edit: this paragraph is nonsense.

So it's very much a back-of-the-envelope kind of thing (I doubt the take-off roll started an exact 2000m from the threshold, either); I don't claim to know what the actual speed was (hence my comment, "in theory").

kungfu panda

13th Oct 2017, 10:06

kungfu panda - as well as passing Perf 'A' I also operated heavy aircraft under hot and high conditions. Of all posters here you are the biggest worry, making absolute declarations, e.g. "I think that it is disappointing that so many professionals fail to recognise that this was not a normal take off."
Based on nothing more than an amateur filming a take off from a passenger seat through a passenger window with a smart phone! Think about it man, it is so ridiculous to not even bear thinking about, you have no supporting technical evidence for your wild claims, for that is all they are. As I said in my first post on this thread, we are largely spoilt by having much more runway than we need, it is only when we get into the heavy aircraft/shorter runway/high temp/humidity/altitude that we start to realise that some runways are just, and only just, long enough. Try Johannesburg, (14000'), on a summers afternoon heading off on a ten hour sector, or Singapore, (13150'), any evening, heading to Europe only a few kilos below the limit for the conditions, both in a B747-400, believe me, runway ahead never disappeared so fast.

Mate- You are clearly the biggest worry on this thread. You appear to have similar experience to me. Both 747 classic, 747-400, DC-10, 777. At hot high airports throughout the world, south America, Africa, Asia, China, Europe.

I have scared the heck out of myself with an overloaded aircraft. As I said in my first post. I was overloaded by 15 tonnes (as it turned out after a re-weigh in Istanbul) out of Dhaka (747-200). We got to 2000' from the end of the runway, still below V1 and Vr. It was clear that at that point, the only option was rotation. At an estimate we crossed the threshold of the opposite runway at 50' and then cleared the roof tops of the city by a little more than that. To me that was very, very close. It is indelible in my memory.

It's just very obvious that the video certainly appears to be much closer than the situation which I had. If company policy is causing these situations to occur it must be looked at.

As described earlier, Boeing suggest crossing the opposing threshold at 150'. It's in the Boeing training manual.

Gordomac

13th Oct 2017, 10:53

Wiggy ; I never got it, still don't. If you are going to reduce your power (we used to call it EPR) in order to increase payload (still don't get it), how much do you reduce ? Got any charts, figures etc ? And, you then want to "take off at Y plus a bit" . How much is a bit ? By getting a reduced V1, I am just beginning to acknowledge a increased VMCG but the rest of the argument has always left me very cold without specific charted info. Digging backwards through charts that give you an increased payload with reduced thrust is for the very brave. As you wipe out the ILS aerials, treetops and blow off a couple roof tops, have more evidence than "reduce" and "a bit", ready for the tea & biscuits.

Capt Fathom

13th Oct 2017, 10:56

As described earlier, Boeing suggest crossing the opposing threshold at 150'. It's in the Boeing training manual
So tell us how you achieve that using your performance application?

16024

13th Oct 2017, 11:01

In line with the last few posts, yes the latest Boeing performance thinking does allow optimisation of assumed temp/de-rate/improved climb all at the same time.
It's unlikely you'd get improved climb on a short runway, though unless there's a howling headwind.
Rummaging through the book, I doubt you'd get de-rate or assumed temp reduction at BRS. *
V1 split would be less than 5kt so the answer to the "would it have flown with a V1 cut?".
Probably.
At our place we have expressed surprise at the amount of runway we seem to be using these days, but if the book says it's fine, eh...?
(Not getting drawn in to the rotation technique in this case).

* That's assuming we are close to perf limiting mass.

kungfu panda

13th Oct 2017, 11:33

So tell us how you achieve that using your performance application?

I didn't say that the 150' is any part of the performance application. What I wish I could do was copy and paste the Boeing training manual. I can not but the reference is page 3.25 Go/Stop decision near V1.

Quote "With Normal takeoff thrust, the airplane should easily reach a height of 150 feet over the end of the runway,"

This clearly indicates that the takeoff in the video was not normal.

Is your opinion that the video shows a normal takeoff?

SStreeter

13th Oct 2017, 11:41

constant acceleration is the "most efficient" way to cover the distance and ends up with the lowest final speed of all possibilities (unless deceleration is involved)

This is off the important point of the thread, but anyway . . .

The formula for constant acceleration is v = 2 * d/t - final velocity is twice the average

(Your formula using 3/2 is true for constant power).

The lowest final speed without deceleration is achieved by being catapulted to average velocity at the start of the takeoff run and then maintaining it.

The important point is touched on in posts above. How much money is saved by using all the runway, compared with using all the available power? Would pssengers be happy about this calculation if they know of it?

wiggy

13th Oct 2017, 11:49

Gordo

Wiggy ; I never got it, still don't. If you are going to reduce your power (we used to call it EPR) in order to increase payload (still don't get it),

As I mentioned to Dan earlier that statement was my :mad:, so I'd refer you to my post to him earlier[/quote]

how much do you reduce ? Got any charts, figures etc ?

Nope there's an "app " of sort for that, :), now whether that app is picking figures out of the wind? BEtter ask the performance engineers, but certainly reduced power and improved climb is a combination in use on Boeings in certain circumstance.

SStreeter..

Would pssengers be happy about this calculation if they know of it?

Would they be happy about the fact we rarely fly anywhere with full tanks?

RobsonCanolo

13th Oct 2017, 11:52

This is usually where a cadet would shine brightly explaining all the ins and outs of the takeoff requirements but i remember many years ago that you need to clear the screen by 35 feet if dry one engine inoperative and that can include a clearway, if there is one. Also assuming the youtube video would have a different name if they were indeed flying single engine, so one issue with what looks like a late two engine takeoff is if they would have the thrust to go single engine from a earlier point than this takeoff and still clear the screen. All in all i wouldnt take poision on either or before knowing more...

SStreeter

13th Oct 2017, 11:59

Would they be happy about the fact we rarely fly anywhere with full tanks?

Of course, if they've any sense: it reduces the takeoff roll (or, as LookingForAJob points out below at 14:49, the thrust required for a given amount of runway).

Musician

13th Oct 2017, 14:16

SStreeter, thank you for correcting me.

double_barrel

13th Oct 2017, 14:54

Of course, if they've any sense: it reduces the takeoff roll.

There is a question I am fully qualified to answer ;-)

I am sure that any pax that thinks about it understands the principle of not carting around needless fuel while making appropriate allowance for alternatives. And fans of cabin pressure understand that max landing weight may be less than the actual takeoff weight!

Similarly, I am sure most would be perfectly happy that takeoff runs are based on appropriate calculations and that you guys don't just blast into the air in the shortest possible distance.

On the other hand, we get a little twitchy when the safety margins seem to be pushed to their limits as in that video. Almost as twitchy as when they run out red wine in business class (KQ, that's you)

Ollie Onion

14th Oct 2017, 03:59

Sorry but that does seem very tight, I don't see why everyone is bagging the kid.... the video is titled 'Ryanair uses the whole runway' and guess what they sure did.

RAT 5

14th Oct 2017, 06:42

I've seen Boeing OPT I-pad and what it can do, but I've never used to operationally. I was the last dinosaur with RTOW tables. I'd looked at what weight we could get off with 29c and then see what ASS Temp was available and note the difference in weights. If the ASS TEMP gave e.g. a 5-6ton decrease then that told me there were plenty of margins and I could choose anywhere between 29c & full reduction. I put my finger in the wind and thought about it. The wind was variable across, perhaps might be a little tail as we reached the hold: it was dampish or worse and there was a lot of rubber - probably- at the other end in the stopping zone; etc. etc. A reasoned judgement was made. The tables allowed you to see the rate at which the weight reduced as temp increased. You had a feel for what was going on.
Then came wiz-bang iPads. Punch in the numbers and with no 'feel' out came the most optimum answer and max reduction and so that's what the guys do, now. No feel, no understanding, no decision. It's max reduction or none, nothing in between. Is that correct?
I was sitting on a 3000m runway, with tables, and the F/O asked if I wanted to use reduced. We looked at the numbers and at max ASS Temp we were still not runway limited. So why not. On our return the runway was shorter, same question. We looked at the table and saw that at 29c we were OBS. This continued until about 38c when it changed to RWY limited. He said we could go to 38c. I said that at 29c we had a LONG runway; at 38c we had converted that into a SHORT runway. Was that wise? OK, we had more thrust at ambient temp than actual assumed, but...To show the company we had thought about it we chose 32c, still OBS. I doubt guys think that way with I-pads. I suspect it is max reduction most of the time with no thought.

Starbear

14th Oct 2017, 07:16

I didn't say that the 150' is any part of the performance application. What I wish I could do was copy and paste the Boeing training manual. I can not but the reference is page 3.25 Go/Stop decision near V1.

Quote "With Normal takeoff thrust, the airplane should easily reach a height of 150 feet over the end of the runway,"

This clearly indicates that the takeoff in the video was not normal.

Is your opinion that the video shows a normal takeoff?

Happy to "help"?

From a B777 FCTM:

It is important to note that the majority of past RTO accidents were not the result of an RTO initiated because of an engine failure. Full takeoff thrust from all engines was available. With normal takeoff thrust, the airplane should easily reach a height of 150 feet over the end of the runway, and the pilot has the full length of the runway to stop the airplane if an air turnback is required.
Making the Go/Stop decision starts long before V1. Early detection, good crew coordination and quick reaction are the keys to a successful takeoff or stop.

FullWings

14th Oct 2017, 08:49

I have been told by finance guys that one of the largest costs involved with the operation of modern airframes is engine maintenance (which can exceed the hull value over its life). The frequency and expense of this correlates very well with thrust/EGT margins on takeoff, so unsurprisingly there is pressure from above to get the job done with the minimum thrust required to meet the regulations.

The performance people have had to get quite creative: we now have AT derates, fixed derates, improved climb, CofG adjustments, packs off, etc. sometimes all used at the same time.

I have noticed over the last few years the end of the runway becoming slightly more prominent on occasions as some of these measures have taken effect but as we are still meeting or exceeding the same requirements as before, it’s more a perception issue than one of safety.

Going back to the video in question, without the FDR and a whole load of other data, I couldn’t definitively say that something was *grossly* wrong with it. A marginally late rotate call followed by a slightly slower rotation rate would produce the effects noticed on the recording, with the correct thrust setting. If they’d carried on at treetop height for the next couple of miles, then yes but that didn’t happen.

BluSdUp

14th Oct 2017, 09:08

Ahhhh! It is refreshing to wake up with fresh coffee, a good zigar and the sun out for a change up here at 60 north.
And some common sense on Pprune. Thanks RAT.

I do not want to speculate on this particular video.

But here is a few observations about the 738-800 with 26 000lbs engine in general and short runways.
Assume runway limited no obstacles: 2011 meter.
Try flap 5 standard: no go
Try flap 15 : just possible if wind is the same in 15 min when rotating.
Try flap 25: Margin for a say 5 kt wind change.
If 25 is tight. do a bleeds off that gives you some 1200kg more to play with.

Now as we all know since we have done so many F15 and F 25 takeoffs, the correct V1 and Vr callouts are critical.
And the proper rotation rate even more, as tailstrike is not an issue : get the 3 degrees going . Mind you to a lover initial pitch.

I have to say we are generally spoiled with plenty of runway and or performance. I see slow rotation quite often on long runways and do not mind.
Doing my initial years on a 1070 meters runway with a close in obstacle at one end and a cliff at the other end I appreciate the need for proper performance.

The I-pad generation , I am not so sure.
" Cpt, Ipad says NO"
" Take away 100kg for taxi!"
" Splendid, now it says GO"

I was on the jumpseat with NOR the other day.One of the options I like is the automated V1 call.

I did get a tad crossed the other day when my FO forgot to call V1- Rotate on a short runway.
No drama , and he is not going to do that again.

Musician

14th Oct 2017, 09:19

FullWings, now those are interesting thoughts. In the AF66 discussion, msbbarratt was wondering why the engine fell apart in cruise and not on takeoff, the strain being greater there than on a simple flight level change in cruise. If that flight took off at reduced power, that might have prevented the engine from coming apart there and then, turning an engine failure on takeoff (and the fan disk dropping off over London) into an engine failure at altitude over uninhabited terrain. Reduced thrust is not all downsides, safety-wise!

fireflybob

14th Oct 2017, 13:31

A marginally late rotate call

Whilst the PM should make the calls at the correct speed, equally the PF should be taking the correct action at the appropriate speed even if the calls are omitted.

MADTASS

14th Oct 2017, 15:01

As someone mentioned earlier, perhaps O"Leary likes to get his moneys worth.

https://www.youtube.com/watch?v=_JyEG6FrIKo

RAT 5

14th Oct 2017, 17:10

Whilst the PM should make the calls at the correct speed, equally the PF should be taking the correct action at the appropriate speed even if the calls are omitted.

Ref a comment in my post about F/O's as PF not observing the instruments during the roll. They are blinkered on the centreline. Fixated. You could ask them a question and they would not hear you. Not good. Takeoff roll should be sharp, alert and relaxed. Tense is not alert; quite the opposite.

In some of my last operators the 'tick in the box' incapacitation scenario is often no PM call at 80kts. PF rejects. Box ticked; let's all reposition to takeoff and leap into the next box ticking exercise. It makes it more entertaining and worth far more if the PF does not respond to 80kts. Even more entertaining is if PM does not call V1 or Rotate; on a runway limited takeoff. That is really an eye-opener and a huge "I won't do that again moment" for PF. The end of the runway, at that speed, approaches faster than an F1 start grid into the first corner. After watching F/O's do blinkered takeoffs it was shocking to see them carry it over into LHS. This 'startle factor' moment served them both well.

ref bean counters. I wait for the day when the statisticians do the maths and decide that the chance of engine failure at V1 is so negligible as to be ignorable. Hey presto; more weight from runway. :ugh:

Euclideanplane

14th Oct 2017, 18:42

I wait for the day when the statisticians do the maths and decide that the chance of engine failure at V1 is so negligible as to be ignorable.
Obviously statisticians might do the maths and figure out some estimate of the chance of engine failure. Obviously a statistician will never be the one to decide whether that is negligible or not. Those calls are made in a higher office.

RAT 5

14th Oct 2017, 20:39

Those calls are made in a higher office.

By Sod who has the thunder-bolts at his finger tips. :rolleyes:

RAT 5

15th Oct 2017, 06:35

The posted photograph in post #65 will answer your question.

Doors to Automatic

15th Oct 2017, 21:06

The Edinburgh take-off was fine. Still 1500ft to go after the aircraft became airborne.

Here is a normal take-off from Bristol. TFS is the destination so likely to be heavy. As I mentioned earlier the plane should be well in the air with 1000ft to go as indeed it is here.........

https://youtu.be/Xge2CC02pTM

The take-off in question on this post was NOT normal. No amount of idiotic criticism of SLF with iPhones detracts from that. In fact it makes me question the judgement of you supposedly professional aviators.

misd-agin

16th Oct 2017, 00:56

cactusbusdrvr

16th Oct 2017, 02:24

Doesn't matter what the weight or flap setting was. Whatever it was it was incorrect for that takeoff. We use balanced field limits for takeoff, a balance between runway available, takeoff thrust settings, flap settings given the weight for that takeoff. Something there was wrong.

Improved climb, where you trade runway for increased rotation speed would cause a long takeoff roll. But given the lack of apparent obstacles off that departure I can't see the need for that type of takeoff. Again, something was not set correctly on this departure, or the crew blew some V calls. The lack of hard, gray surface in front of you is usually a good indication that you need to be flying.

And my resume is 28k hours, typed in 737/757/767 and Airbus 320 family.

kungfu panda

16th Oct 2017, 03:08

Talk about the height of hubris. Are you even a pilot? Pilots are trying to tell you that given the information available they can't tell you if the takeoff was or wasn't normal and you, perhaps as a non pilot, are calling us "supposedly professional aviators"? What was the aircraft weight in any of the examples you're comparing? Flap settings? TO? TO1? TO2? Any derates used? Does that matter?

What's your "professional aviator" resume?

This was not a normal take off. You must question the professionalism of those who suggest that achieving almost no altitude at the piano keys of the opposite end of the runway is a normal takeoff. :ugh:

parabellum

16th Oct 2017, 04:26

Kungfu Panda - You don't give up, do you?

This was not a normal take off. You must question the professionalism of those who suggest that achieving almost no altitude at the piano keys of the opposite end of the runway is a normal takeoff.What you have seen on the video clip is not acceptable as evidence, in any form. Please post the factual evidence, i.e. hard figures, independently recorded and obtained that you have to support your claim and you may wish to consider the phenomenon of optical illusion whilst you are gathering those numbers..

But given the lack of apparent obstacles off that departure I can't see the need for that type of takeoff. Again, something was not set correctly on this departure, or the crew blew some V calls. The lack of hard, gray surface Another wild statement posted cactusbusdriver, without a scrap of factual evidence to support it.

misd-agin - great post! I think we can see how public hanging by lynch mobs came about! ;)

Capn Bloggs

16th Oct 2017, 05:24

https://s26.postimg.org/64y8cibnt/Pucka.jpg (https://postimages.org/)

RobsonCanolo

16th Oct 2017, 05:51

Kungfu Panda.

Have a look in the easa regs performance class c and among many things there and assuming no other limiting factors for this takeoff you only need a takeoff run not exceeding the takeoff run available. so from a performance standpoint and with said assumptions it is acceptable to just be airborne at the far end.

EGPFlyer

16th Oct 2017, 06:48

Except the 737 is perf class A...

RobsonCanolo

16th Oct 2017, 07:07

Ok but it’s the same for class a. The takeoff run should not exceed takeoff run available. So again it’s thin ice to say anything is wrong imho.

parkfell

16th Oct 2017, 07:20

Parabellum

I would suggest that notwithstanding the video was taken by a phone, it does provide prima face evidence.
There might be a valid explanation for what we see, but can you say it is perfectly normal for Bristol?

I would be interested to know why an optical illusion might to have occurred? It seems an uncomplicated picture (Capn Bloggs) to me.

You are starting to become hysterical ~ lynch mobs; really?
Instead of taking a swipe at everyone, how about explaining why it is perfectly normal.
You are simply whipping up further interest in the event. Calm down

sleeper

16th Oct 2017, 07:34

Mr Parabellum. Why on earth are you trying to belittle the iphone video. There is no optical illusion at all. The aircraft clearly is only just airborne when the runway ends. There is no way around that and it is absolutely not normal. And before you dismiss me as well, I am a professional too.

PT6Driver

16th Oct 2017, 07:50

Just a reminder that in today's world derated, assumed temperature and improved climb are the normal defaults when making takeoff calculations at all airports, as this helps with engine maintenance costs amongst others.
Also at Bristol the clearway will be taken acount of in the calculations.

jack11111

16th Oct 2017, 07:57

RobsonCanolo wrote:

"Ok but it’s the same for class a. The takeoff run should not exceed takeoff run available. So again it’s thin ice to say anything is wrong imho."

OK, let me get this straight...as long as I don't use the grass at the end of the runway, it's all good!! OMG!

jmvdb22

16th Oct 2017, 08:02

As long as you don't hit anything else as well :8

Right Way Up

16th Oct 2017, 08:09

The takeoff run should not exceed takeoff run available

But that assumes you lose an engine at V1!

RobsonCanolo

16th Oct 2017, 08:34

jack11111 Perhaps it’s better to ask you to point out how high you should be at the far end instead? Reading through the regs EASA i don't see any such limit but perhaps you are right if airlines add additional constraints in the takeoff data calculations but knowing the industry for some time now i have serious reasons to doubt that.

If you want to maximize the payload for a given day and runway there is no need for more runway ahead since you are already committed at an earlier point to go. Clearly there are issues with margin and assuming a proper technique and as always other assumptions in play, it’s at least from a performance standpoint i don't see an issue not using the whole runway for the run if needed.

But that assumes you lose an engine at V1!

It means at V1 you need to take the first action to stop or if deciding to go you still have the performance to go. And if deciding to go it means you still should be able to be airborne at the far end taking into account the lower acceleration due to one engine.

Flap config, derate, assumed temp, bleeds, etc are just the variables at hand to get to the point where things work out for a given payload and data to minimize costs wear and maximize payload which i don't see any reason for them not trying to go for at every takeoff.

RAT 5

16th Oct 2017, 08:36

And you are supposed to Stop by the end of the Stopway; if you execute the stop no later than V1-ish, give or take the current 1 or 2 seconds. And looking at he photo in post #65 there doesn't appear to a lot of stopway. And given that the braking action of grass is unpredictable, but certainly significantly less than tarmac, how they ever make a sensible calculation that you should stop within the stowaway defeats me. I wonder what coefficient is used for the last bit: it can't be the same as tarmac, unless they factor in the wheels sinking up to the hubs, but that doesn't happen instantaneously. It's not like an F1 gravel trap.
We'd need to know where on the runway V1 was called & Vr and how the rotation was executed to be sure of anything; but I can categorically say that on all the diverse european runways I've operated from, B732/3/4/7/8, I don't remember seeing the end quite so close as that. I suspect the wheels were still down as the crossed the end of the tarmac.

It does concern me that, with i-pad performance, there seems blind faith and little understanding of what is going on when the numbers are entered into the FMC. Pilots do their CPL & Perf A course. They know the rules inside out. Yeah, but what do they really mean and what does it look like 'on the day'? They then assume, correctly, that the i-pad has all the reg's in the program and the numbers in will give the correct legal numbers out. But that has removed all 'feel' for what is going on. It's just another 'magenta line'.

I used to teach the 'gross error check' philosophy, especially with takeoffs & load sheets, TOD's distance to go, etc. Guys asked, "what's the point? We have the FMC" "So you have a feel what what's correct and not, and because some other guy made the load sheet, but I sign for it, and because I don't always trust the FMC. It's tool not my wife who must be obeyed." And now there is the i-pad.
Sure enough we detected a 10ton error in the load sheet. One day someone else didn't and they had a tail strike.
Same with performance. If the calculated N1% seems too low, it probably is. But you'll only know that if you have an idea of what is a correct range; i.e. paid attention on previous trips.

Doors to Automatic

16th Oct 2017, 09:41

This was not a normal take off. You must question the professionalism of those who suggest that achieving almost no altitude at the piano keys of the opposite end of the runway is a normal takeoff. :ugh:

Yes, precisely the point I was making. Those that dismiss the "SLF" and claim that this might have been a normal takeoff hiding behind jargon connected with weights, N1s, Power settings etc are the ones I was referring to.

Right Way Up

16th Oct 2017, 09:58

It means at V1 you need to take the first action to stop or if deciding to go you still have the performance to go. And if deciding to go it means you still should be able to be airborne at the far end taking into account the lower acceleration due to one engine.

Flap config, derate, assumed temp, bleeds, etc are just the variables at hand to get to the point where things work out for a given payload and data to minimize costs wear and maximize payload which i don't see any reason for them not trying to go for at every takeoff

All very good but if you are starting to rotate 5 seconds from the end of the runway with both engines running something has gone wrong.

Also if they did indeeed use an assumed temperature there should have been even more margin. From the sounds of the flight they were carrying out I reckon it is more likely they were using close to max takeoff thrust with little if any flex.

Chesty Morgan

16th Oct 2017, 10:00

Well they had about 600' altitude at the piano keys. No big deal then?

Capt Fathom

16th Oct 2017, 10:16

Why waste good runway. You are paying for it after all.

RobsonCanolo

16th Oct 2017, 10:19

RAT 5 Well if you end up in the grass then you tried to stop to late or didn't get the speedbrakes out or brakes on or whatever in time... Do you know what speed V1 was in this case?

Also as far as i am aware i haven't heard anyone thinking that common sense as well as help such as performance tool or loadsheets are putting anyone at a disadvantage in life... But i trust EASA to know what they are talking about at least...

Right Way Up

16th Oct 2017, 10:29

I don’t believe regulations are being questioned here. It is whether the performance was correctly calculated. That is where RAT5s common sense thought comes in. Does it look right?

parkfell

16th Oct 2017, 10:40

I find it hard to believe that if everything had been a strict text book launch (applying EASA criteria) then you would end up with the unstick point so close to the end of the runway.
Something clearly went wrong either with the timing & Vr / rate of rotation /
thrust used or a combination of these, and other factors.

It simply cannot be right.......

I entirely concur with RAT5.......... he uses "feel".......my choice of word is "empathy".......

We need the likes of the late Sandy Thomson to teach performance to these junior birdmen. I sure they are out there , not just to teach to pass the exam, but to impart an understanding of what the hell is really going on.

Capn Bloggs

16th Oct 2017, 10:43

It means at V1 you need to take the first action to stop or if deciding to go you still have the performance to go. And if deciding to go it means you still should be able to be airborne at the far end taking into account the lower acceleration due to one engine.
If they were only just airborne over the threshold with two engines going, how do you think they'd go had an engine failed just after V1?

DaveReidUK

16th Oct 2017, 10:52

And looking at he photo in post #65 there doesn't appear to a lot of stopway.

Zero, in fact, as pointed out a couple of times previously in the thread.

Right Way Up

16th Oct 2017, 10:52

There is a certain amount of sensitivity about discussing this takeoff and appear to be criticising a crew, but personally it is much better being able to dissect this sort of incident and learn from it then having to wait for an AAIB accident report. There are too many lucky takeoffs occurring around the world where people are getting away with it......at some point someone and hundreds of passengers will not be so lucky

Doors to Automatic

16th Oct 2017, 11:17

I saw an exceptionally tight one at Richmond, VA a while back:
https://youtu.be/wtk0OEK2E9M

I actually think the Ryanair one is worse!

misd-agin

16th Oct 2017, 14:08

So was the Delta flight unacceptable? Anyone asking that that flight be investigated? Or is that what a takeoff at runway limited weight looks like? It can be uncomfortable looking out the front window at V1 at the remaining runway and we're often left thinking "well officially this was supposed to work."

But without knowing the performance facts for the flight using that camera angle instead doesn't show proof of harm. I've seen enough weight limited departures to not be astounded at the video.

And check out the difference between rotation rate, and initial pitch attitude, in the Delta MD-88 and the 737-800 videos. Anyone who's flown both models knows why the reason for the difference.

OldLurker

16th Oct 2017, 14:34

... but personally it is much better being able to dissect this sort of incident and learn from it then having to wait for an AAIB accident report.True (IMHO), but nobody will learn from this one. Enough pilots here are saying no, nothing to see, move along now ... we might as well give up discussing it. There won't be anything useful out of the AAIB on this incident (if it's a reportable incident at all) even if it was reported (unlikely) because there's no evidence apart from this amateur video from a questionable viewpoint – the recorders will surely have been overwritten long ago.

Dufo

16th Oct 2017, 15:56

If they were only just airborne over the threshold with two engines going, how do you think they'd go had an engine failed just after V1?

Knowing the exact data could answer your question.

Improved climb Vr/V2 are significantly higher than 'normal' ones but could have same V1 as 'normal' takeoff.

pattern_is_full

16th Oct 2017, 18:02

Just for the record, a video showing the "clearway" off the end of 27 at BRS (aircraft lining up for TO from 09). Which is, by the definition, effectively "infinite" since the ground falls away for a mile or more.

https://youtu.be/ZoQQ9AoKhwk?t=4m38s

OTOH, while there is no actual rule about where rotation should occur on the hard surface, relative to runway remaining, nightime centerline lights give a rather strong hint. They turn solid red with 1000 ft/300m remaining.

To me, that says "you really don't want to still have all your gear on the ground entering this area."

If your little green calculator still has you slower than Vr passing 300m remaining, IMHO, you were just a bit too "cute" in your programming assumptions.

OTOOH, I'm sure that the calculated V1 in the takeoff shown originally was adequate for ASDA. But suppose there was a loud "bang" right at Vr in that situation? Startle-factor, reaction time - would that have delayed their "just in time" rotation long enough to put them into the grass and approach lights?

EDMJ

16th Oct 2017, 18:30

If passing the piano keys at this "altitude" is accepted and legal practice in the airline industry - as some insiders vociferously suggest here - then I seriously need to reconsider my future air travel arrangements.

misd-agin

16th Oct 2017, 18:52

The typical airliner departure isn't anywhere near the runway limited weights. Departures on runway weight limited weight flights use a lot of the runway. The flight in question was probably very near, or at, the runway limited weight.

As pilot observers we listen to engine noise (level of thrust being used), intial acceleration (indication of weight or thrust being used), rotation point, and initial climb rate to estimate the weight of the a/c we're observing.

Just like the videos of the 'Vodka bomber' show certain flights are known to be heavy. UK to TRS from a 2100 meter runway would be worth watching or videoing. Maybe other videos of the same flight number, and the same passenger load, would show if this departure probably was, or wasn't, normal.

kungfu panda

16th Oct 2017, 19:03

Jwscud

16th Oct 2017, 20:53

Departures at BRS to the canaries in a 738 on hot and/or calm summer days tend to be approaching TOPL. I've done one or two! The amount of runway left at V1 on a bona departure at TOPL as others have said is pretty sobering, and a good reminder of why we are go-minded above 80kts!

If there is any doubt, it was sop when I was at Ryanair to email a copy of the Boeing OPT output to mother so they'll have a record of what was input into the EFB. They will also still have the load sheet so a simple gross error check in that respect would be possible. The QAR data may well also be available depending on the time elapsed since the incident.

CABUS

16th Oct 2017, 21:03

I checked this thread out and thought it was just another back seat flyer post however after seeing the video it was obviously too low. Anyone can read Perf A and quote it chapter and verse but when when you watch that and think 'bl**dy h**l with an ounce of experience you know it was wrong. I think we can all be in agreement for one reason or another too much runway was used.

fireflybob

16th Oct 2017, 21:07

Legally clearway must be within the Airport boundary and controlled by the Airport Authority.

Are you sure? RW27 at Bristol has 1000 metres of clearway which I'm sure is outside the airfield boundary.

Or do you mean Stopway?

EMIT

16th Oct 2017, 21:26

And the answer is ....
(EU OPS)
clearway’ means a defined rectangular area on the ground or water under the control of the appropriate authority, selected or prepared as a suitable area over which an aeroplane may make a portion of its initial climb to a specified height;

And about braking index of grass .......
accelerate-stop distance available (ASDA)’ means the length of the take-off run available plus the length of stopway, if such stopway is declared available by the State of the aerodrome and is capable of bearing the mass of the aeroplane under the prevailing operating conditions;

..and where I have written EU OPS, of course it is now EASA Ops, full title of the literary masterpiece is Regulation (EU) 965/2012 on air operations.

fireflybob

16th Oct 2017, 21:33

EMIT thanks, so (understandably) "under control of the appropriate authority" but no requirement to be be within the airport boundary.

AERODROME OBSTACLE CHART - ICAO (http://www.nats-uk.ead-it.com/aip/typea/NATS_AIM_TypeA_Bristol-EGGD_09-27.pdf)

From CAP 168:-

A clearway need not have bearing strength and may be land or water. It may extend outside the aerodrome boundary only if the aerodrome authority establishes such control that will ensure that the clearway will be kept free from obstacles or that the clearway plane will not be infringed.

parabellum

17th Oct 2017, 00:39

You are starting to become hysterical ~ lynch mobs; really?
Instead of taking a swipe at everyone, how about explaining why it is perfectly normal.
You are simply whipping up further interest in the event. Calm down Really Parkfell, hysterical? It the likes of the, "It wasn't normal" who are whipping up the interest now and need to calm down. Many of us have said, that on a limiting runway, at heavy weights, you can expect to get a very good view of the runway end. As I have said already, twice, we are generally spoilt by the amount of runway available and only realise how much runway a 'hot and heavy' take off uses when we are faced with one, like Bristol, in this case or my own ten years experience with heavy B747s out of Singapore and other places, not to mention thirty previous years, worldwide, in a variety of aircraft in a variety of different countries.

It wouldn't need anyone with more than an 'A' level in physics to refute that the video shown here is acceptable as an accurate scientific record.

And parkfell,
misd-agin - great post! I think we can see how public hanging by lynch mobs came about! ;) Do see if you can resurrect your sense of humour, yes?

kungfu panda

17th Oct 2017, 00:50

Are you sure? RW27 at Bristol has 1000 metres of clearway which I'm sure is outside the airfield boundary.

Or do you mean Stopway?

I am sure, it's a quote from the FAR/AIM. I know that's FAA but it applies worldwide. Clearway must be within the Airport boundary and under the control of the Airport authority.

I presume that the Airport perimeter road at Bristol Airport is owned and controlled by the Airport despite being open to the public.

It stands to reason that clearway must be controlled by the Airport, otherwise anybody could put up a 35' crane in the flight path.

RAT 5

17th Oct 2017, 07:28

I've missed if anyone knows where the flight was bound for. If someone does, and there are any B738 operators reading this with their i-pads handy, perhaps they could crunch some numbers for a full load and enlighten us. I would be interested if this was a F5 full chat or not.
I remember one day, B757, when the end of the runway seemed to be coming up faster than usual on a reduced take off day. Option, increase thrust; we'd gone past VMCG, but in any case....... It turned out to be a mirage and optical illusion. Unlikely at BRS, but I'm curious if there was more thrust available. I didn't detect any increase in engine sound. Afterwards, a pilot mate of mine (in the days when you could) came for a chat and asked what happened. He'd felt & heard the increase in thrust to full umph.

fireflybob

17th Oct 2017, 07:36

I've missed if anyone knows where the flight was bound for.

I think it was Bergerac - my guess is it would be a tankering sector.

fireflybob

17th Oct 2017, 07:41

Clearway must be within the Airport boundary

kungfu panda, I agree that clearway must be "under control of the airport authority" but in the UK (as the definition in CAP 168 which I have quoted above shows) it does not have to be within the airport boundary.

Under "control of the airport authority" and "within the airport boundary" are not necessarily the same thing.

Semantics I know but I can think of one or two airports in the UK (including BRS) where the clearway extends outside the airport boundary.

The Ancient Geek

17th Oct 2017, 08:05

For the non-pilots reading this, Clearway and stopway are two different things.
A stopway is an area beyond the designated runway available as extra stopping distance. It may be surfaced with an energy absorbant material. This is clearly inside the airport boundary with no obstructions. Bristol does not have a stopway.
A clearway is a fan shaped area beyond the runway with no obstructions above the minimal angle of climb. Runway 27 at Bristol has no obstructions beyond the ILS antennas because the ground falls away so if you can clear the ILS you are away free. Other airfields will often have buildings, trees etc obstructing the approach and climb out paths to consider.

fireflybob

17th Oct 2017, 08:32

I presume that the Airport perimeter road at Bristol Airport is owned and controlled by the Airport despite being open to the public.

Bristol Airport (https://www.google.co.uk/maps/@51.3806412,-2.7343578,5224m/data=!3m1!1e3)

If you extend the RW 27 centreline from the eastern end of the runway by 1000 metres which is near enough the amount of clearway the clearway extends well outside the airport boundary. Other than the minor road just off the western end (which would I'm sure be under control of the airport authority) the only other public road is just east of the RW 27 threshold. For this reason RW 09 only has about 60 metres of clearway.

parkfell

17th Oct 2017, 09:12

Talking of CLEARWAYS ( a clear divergence from topic) , when Sumburgh (Shetlands) did their extension of runway 09/27 using 70,000 tons of rocks imported from Scandinavia circa 2005,
the runway extremities ended by a sea wall either end.

And as the airport was not able to prohibit boats from entering the areas along the extended centrelines, it could not be used as a CLEARWAY.
Not that I could ever recall seeing a boat in what would be the potential "defined areas".
Yes, the area must be CONTROLLED by the airport authority.

OldLurker

17th Oct 2017, 13:24

DaveReidUK

17th Oct 2017, 15:00

I think it was Bergerac

Correct, as the link in the very first post of the thread makes clear.

Herod

17th Oct 2017, 15:27

When I was still working, I occasionally took a -700 from Bristol to Banjul, some 2,400 nm, approaching 6 hours flying time. A full passenger load, and a fair amount of fuel. It's certainly not the longest runway in the world, but it was doable.

The Ancient Geek

17th Oct 2017, 16:14

It doesnt matter how long the runway is, someone will always struggle to get over the fence. A good example is Harare (previously Salisbury) at 4725m which is best tackled at night. Afternoon departures are a BAD idea.

FullWings

17th Oct 2017, 21:52

There have been some very relevant posts about operating aircraft at the limits of performance. If you’re used to moderately loaded twins out of 3,000m+ runways in benign conditions, then doing the same thing at WAT limits can be quite educational.

I flew a 777-300 out of HKG in the summer at RTOW and had my eyebrows raised enough to flag the takeoff to our perf guys to see if there was anything untoward about it - which there wasn’t. With Vr nearly 180kts, boy does the end of the runway come at you quickly. I’m not sure what it would have looked like on video but it didn’t feel that high over the opposite threshold. Lucky it was dark! Reminded me of NBO, feeling that I was starting a game drive...

As pointed out in previous replies, on a short runway using maximum performance, you only have to be slightly late/slow in a few areas to make the resulting takeoff *look* marginal on two engines. However, if you lost a power plant at V1, the slower acceleration and extra adrenaline would probably lead to following the planned flightpath with a bit more accuracy. If the clearway at BRS was included in their calculations, then as long as the wheels leave the paved surface before the end of it, they had 1,000m+ to make the 35’. In practical terms, as the ground falls away it doesn’t really matter, although the performance would always be calculated to leave at least this margin.

cactusbusdrvr

18th Oct 2017, 05:38

Talking of clearways: There are many runways that end at the water's edge. My sailing has never taken me past one, but surely there must be maritime measures in place to prevent, or coordinate with, shipping movements past the ends of such runways?

SXM comes to mind: it would have been, let's say, interesting to have been in a boat on the extended centerline at the time of the Westjet incident (http://www.pprune.org/rumours-news/592054-so-westjet-almost-puts-one-their-737-water-while-landing-st-maarten.html) in March.

KBOS has a chart note that calls for higher minimums when large ships are in the channel on the approach to 04L and 04R. I think we have a performance penalty for departing the 22s as well. The ATIS will designate "ships in the channel".

About a year ago we were flying into PHLI (Lihue on the island of Kauai). A cruise ship had just departed Nahiwilli harbor and I tried to time our approach to fly over the ship but, alas, it was a little too late for us. Those cruise ships certainly stand out off a rural island.

RAT 5

18th Oct 2017, 07:14

On another thread I asked the question and the answer was that Clearway is limited to 50% of TORA. It can't go on forever. I must admit watching some a/c seem to struggle their way over the fence. BAC1-11 was one. I wonder what would have happened on only 50% of thrust. I've even watched some 4-pots freighters seem to climb very flat & slowly and wondered what would have happened on 75% of thrust. Faith. In this BRS case I'd have been more concerned about the 'stopping' case, if it had been necessary. It has been said that TORA = ASDA. It seems it would have been very tight.
Still waiting for some B738 pilots to post their i-pad numbers for BRS RW27.

Gordomac

18th Oct 2017, 10:25

RAT 5 : I used to wonder in the same manner. I transferred from B767 to A340 in my last year. A hot, heavy B767 for LHR; Open the taps and there was that re-assuring thump in the small of the back. V1 call was pretty rapidly followed by VR in the same breath. Landmarks like terminal buildings, freight bases, crew car-parks seemed to whizz underneath . SNY on the scarebus was my intro. No throttles, funny little idents but Perf A is what we are all on about. Hot, heavy for LHR. No re-assuring thump in the back. Could have placed my breakfast order while awaiting the V1 call. Waiting for VR alerted me to a double pilot incapacitation situation possibility. NOTHING whizzed underneath but there was a slow passing by of the terminal, freight bases, crew car parks, Mcdonalds and a couple of fishing craft where crew had dived into the water watching our approach. Piano keys ? I think we played the National Anthem on them.

After settling down, I asked my intro Captain what the thing was like with two engines out, same side, j e r s t after V1. I got a concerned look with the response...." we don't even THINK about stuff like that ."

In this discussion, I am siding with Parabllum's highly experienced and admired posts. Pax in the terminal with hand held devices will have observed me in my Boeing lift off abeam the terminal. In my A340, I often wondered who might be filming my lift-off, same conditions, bit heavier but powered by four hair driers as we got a level view of new building projects in the harbour area !

Oh, can't resist a playful prod;- Yet, there are some who will try and convince that if we REDUCED thrust, we could have lifted off an even higher RTOW. Cripes, glad I joined the PERF A burning books ceremony after passing the exam !

AerocatS2A

18th Oct 2017, 10:44

A 4-holer will be more sluggish on all engines than a twin because it only has 33% more power available than that required to meet the OEI performance requirements. The twin has 100% more available.

procede

18th Oct 2017, 14:52

Not quite, single engine out climb requirements are lower for a two engined aircraft. Then there are higher all engine operating climb requirements (due to
PANS-OPS) that even it out a bit.

neila83

18th Oct 2017, 15:41

Really Parkfell, hysterical? It the likes of the, "It wasn't normal" who are whipping up the interest now and need to calm down. Many of us have said, that on a limiting runway, at heavy weights, you can expect to get a very good view of the runway end. As I have said already, twice, we are generally spoilt by the amount of runway available and only realise how much runway a 'hot and heavy' take off uses when we are faced with one, like Bristol, in this case or my own ten years experience with heavy B747s out of Singapore and other places, not to mention thirty previous years, worldwide, in a variety of aircraft in a variety of different countries.

It wouldn't need anyone with more than an 'A' level in physics to refute that the video shown here is acceptable as an accurate scientific record.

And parkfell,
Do see if you can resurrect your sense of humour, yes?

Yes, everyone knows that when heavy, hot, short runway etc etc you will use a lot of runway. That's stating the obvious. What's not supposed to happen is to use this much runway. If you have any basic physics you'll know if you only get airborne with that much runway running with both engines running, something isn't right.

A 'hot and heavy' takeoff does not leave this much runway remaining, and if your'e a professional and you think so that's a concern. Aviation safety isn't built on those kind of margins, with one engine out you'd expect to at least have started getting airborne earlier than this.

What are you suggesting about the video by the way, is it faked? I assure you when incidents occur the investigation authorities take such video evidence very seriously if it is available and it is a major aid in establishing the chain of events.

misd-agin

18th Oct 2017, 16:08

A better aid to establish any chain of events is the FDR, FMC/IRS/GPS data, etc.

RAT 5

18th Oct 2017, 17:45

Yes, everyone knows that when heavy, hot, short runway etc etc you will use a lot of runway.

Someone suggested this flight was to Bergerac. That would be about 1.30hr. It might have been a tanker sector. That would sue a total fuel load of 4.00hrs. That's about 10tonnes. However, landing wt limit would have restricted the RTOW to about 68tonnes. With 26K available and a choice of flaps that is nowhere near a runway limit takeoff; unless you make it one.
If Bergerac was there true destination.

I've read the report on the AC A320 from BFS that took out a light at the far end. Wrong temp entered in FMC and a ridiculously low N1% computed and accepted. No awareness and just dumb acceptance. What is scary is that the crew acknowledged that they thought acceleration was slow passing 120-130kts. The end must have looked very close and yet they did not increase thrust until 800'. Come on! It's too late then. They were 12% too low on thrust setting and no alarms. OK, but not to increase thrust on the roll is suicidal.

waflyer

18th Oct 2017, 18:01

Gordomac - your post #184 is perhaps the best (and most entertainng) post I've ever read on PPruNe. Yours and RAT 5's are my favorites.

Back to the beginning of the thread - if the 'amazing' take off of Ryanair at BRS, as shown by a creditable video, is a result of someone's idea to use less than 100% under the existing conditions in order to save 'maintenance money' - than I think it's time for everyone to take a 'time out' and talk!

Long time lurker - first time poster

Musician

18th Oct 2017, 18:13

I downloaded the video (https://www.youtube.com/watch?v=Q8MdBVHF-_g), used SMPlayer to split the interesting bits into single frame images, and picked those frames where runway markers were visible, judging the plane's position by the shadow of its wing. This method is somewhat inaccurate because somewhere in the chain some duplicate frames were inserted (possible to change the frame rate from 25 fps to 30 fps) and the shadow moves as the wings lift up, so when I state that the plane had 40kt at the threshold marker, 125kt at the center of the runway and 150kt over the aiming point, those values are probably fairly close to the truth (maybe +/-2kt?), but ultimately useless.

However, I then cut out images of the 8ft tall winglet in those positions where the wing was over a runway marker (two images for each set of "piano keys") and aligned them at the runway edge. This makes it easy to see where the plane rotated and lifted off: 450m (1500ft) from the end of the runway, rotating at approx. 1° per second.

http://www.pprune.org/attachment.php?attachmentid=3390&stc=1&d=1508349742 (http://www.pprune.org/attachment.php?attachmentid=3389&stc=1&d=1508349469)

Small print: 0s is at 1:57 in the video, as the back edge of the wing's shadow aligns with the back edge of the "piano keys" (this position is 0m). Pictures 3-12 have the same positional relation to each touchdown marker. The runway image was taken from Google maps and provided me with the positions of the runway markers, assuming those were painted in multiples of 5m. The first attachment is full size, 824px is half size for including in the post.

PT6Driver

18th Oct 2017, 18:16

Waflyer
The days of using max thrust are long gone, except when absolutely necessary. Otherwise reduced thrust, assumed Temp improved climb etc are normal.

RAT 5

18th Oct 2017, 19:04

Even worse, perhaps. In previous years there was a maintenance requirement to execute full power take every few weeks/months? In late 90's I joined an airline whose network never required a full power takeoff. So I asked the question from engineering to be told it was no longer a requirement. They could tell from 'data' if the engine was operating to spec. I wonder if that was another 'cost saving' decision. There will be those who know better,

DaveReidUK

18th Oct 2017, 19:23

A better aid to establish any chain of events is the FDR, FMC/IRS/GPS data, etc.

Agreed, a decent ADS-B/EHS capture log would go a long way to answering some basic what/where/when questions.

FR24 is of limited use because of its sparse coverage of the aircraft on the runway, although it does confirm that the aircraft was sending ground (rather than airborne) position transmissions as it passed the 09 aiming point, meaning that it had weight on wheels at the time, 1100' from the runway end.

underfire

18th Oct 2017, 19:37

KBOS has a chart note that calls for higher minimums when large ships are in the channel on the approach to 04L and 04R. I think we have a performance penalty for departing the 22s as well. The ATIS will designate "ships in the channel".

I see the add for the LPV approach, but no others, and even that seems a bit odd. For the procedure design over water, you are supposed to add a 200' AAO obstacle just for ships. Simply adding this note to the plate is a bit of a disaster in the making.

Agreed, a decent ADS-B/EHS capture log would go a long way to answering some basic what/where/when questions.

Unfortunatley, the broadcast frequency is not really enough to tell, and weight off wheels is not a required broadcast.

DaveReidUK

18th Oct 2017, 19:52

WOW is implied by the transmission type, and a full ADS-B capture would have 0.5 second granularity, enough to provide a pretty good picture of what happened.

But we don't have one, so it's all a bit academic, apart from that one known data point.

Musician

18th Oct 2017, 20:27

The horizon is not up yet on the video as the plane passes the last touchdown marker (@150m/500ft), but the cameraperson is sitting in the back, so may be rotated down slightly?

Mr Optimistic

18th Oct 2017, 21:43

Sillert,V.I.

18th Oct 2017, 21:49

Talking of clearways: There are many runways that end at the water's edge.

LXGB comes to mind; a not overly long runway with water at both ends, and disputes over the ownership of said water.

DaveReidUK

18th Oct 2017, 21:53

March 2016 so any ideas why this has surfaced only now?

No, July 2017.

Mr Optimistic

18th Oct 2017, 22:02

Ah, thank you: was puzzled. Polite little chap giving the commentary.

Musician

19th Oct 2017, 01:14

[pax] March 2016 so any ideas why this has surfaced only now? Still, can't have been that hot in Bristol if the date is right: nice weather though. Incidentally is analysis of #191 consistent with #132?
Thread started off this video uploaded August 18th 2017: https://www.youtube.com/watch?v=Q8MdBVHF-_g
In #29, megan posted one uploaded March 26th 2016: https://www.youtube.com/watch?v=fACX1DvwhpM

On the 2016 video, the plane does everything ~150m/500ft sooner, I'm attaching screenshots over the last 3 markers. Note that the plane has liftoff on the aiming point, you can see the mist trail from where the wheels were still on the ground; and also note it is at approximate winglet height over the last marker.

I'm not sure which analysis you're referring to, #132 (http://www.pprune.org/rumours-news/600731-ryanair-uses-all-runway-7.html#post9926376) shows a screenshot from the video and no text? Observations re: the rotation and liftoff were made by Capt Fathom (#36), wiggy (#54, #92), roy747 (#65), and RightWayUp (#82), the screenshots pretty much confirm those, but I like to think my efforts are more precise. (I wouldn't have had a hope of observing as much as these guys just from watching the video, though.)

condor17

19th Oct 2017, 07:39

msjh

19th Oct 2017, 07:53

Most short haul 2 engine jets that I've flown get to Vr at about the 30 secs mark . So TLAR [ that looks about right ] . Seem to remember the rotation rate that I was taught was about 2 1/2 degrees per sec [ 6 secs to 15 degrees pitch ] .Therefore lift off is a few seconds later that rotate .
Longhaul , 2 or 4 eng ; Vr at about 45-50 secs . Very longhaul or hot 'n high , Vr at about 60 secs or more !

rgds condor .

(Writing solely as a passenger: I am not an airline pilot)

If you've ever been on a 747 taking off from Johannesburg to Europe, a 60+ second take-off roll was standard. But then it's at 5,500' altitude and flying distance to London is 5,600 miles/9,000km. Runway 03L in JHB is 4,400 metres/14,000 ft long.

framer

19th Oct 2017, 09:23

Someone said a while back that they worked out a rotation rate of 1degree per second.
If that's accurate it explains the whole thing.

Snyggapa

19th Oct 2017, 11:10

I guess that's why there are safety margins built into everything - if rotation was late or slow, that counts as a failure and has used the safety margin as visibly seen.

It has also removed the likely margin for a second failure (human or technical) so there is a question as to whether the margins are sufficient, or are they only designed for a single "failure" event and a double failure is deemed unlikely enough to happen.

In some ways the system has worked in that an apparent failure has not caused a catastrophe, but in other ways it reveals the flaws, but where do you stop...

simmple

19th Oct 2017, 11:19

Ok it’s not normal, but only today I delayed the rotate call to avoid the large flock of birds that crossed the runway infront of us.

roving

19th Oct 2017, 12:17

As self loading freight carried in and out of Bristol, I do wonder whether your post underlines the concerns raised by some posting here.

It has been suggested by some with a better technical understanding than me, that the likely reason that the aircraft shown in the video made full use of the limited runway at Bristol was because it was using reduced thrust.

If a decision had to be made on this aircraft to delay the rotate call to avoid a large flock of birds crossing the runway, what would have been the consequence?

Lodems

19th Oct 2017, 12:39

The thread has crept somewhat but throughout my longhaul career I was fairly certain that most of the so-called safety margins were very marginal but could somehow be justified on paper. Max weight (over?) 747-100 departures from Caribbean islands were usually a matter of holding your breath just after rotation and hoping that the gear didn't hit anything on the boundary. Similarly at very low temperatures out of Anchorage trying to accelerate and climb.Or Nairobi with runway temperature quoted in 1/2 degrees to fiddle the book figures. 3 engines shortly after V1 would have been interesting. Fortunately the first generation of 707 and 747s IIRC didn't have the added potential for cockups of reduced thrust take-offs. As a young F/O on a very hot and humid Lourenco Marques departure I called rotate, the a/c lifted off briefly and then settled back on the r'way. The second attempt succeeded-just...

.Scott

19th Oct 2017, 13:30

Despite comments in this thread to the contrary, meaningful metrics can be collected from cell phone video.

In this case, I am looking at the shadow of the wing to judge the relative position of the 737 at it crosses runway landmarks.

Here's is what I note:
2:11 Early edge of taxiway H. About 1475 meters of runway remaining.
2:21.5: Middle of retired taxiway. About 780 meters of runway remaining.
2:27: End of bar at outside edge of runway. About 356 meters of runway remaining.

So, in that last stretch, the 737 crossed 424 meters in 5.5 seconds. Averaging 77 meters per second or 150 knots.

That's averaging roughly 150 knots.
At that point, he still had 350 feet on runway in front of the wing - but did not rotate for another second.

So as best I can tell, this was a delayed rotation.

Musician

19th Oct 2017, 14:15

So, in that last stretch, the 737 crossed 424 meters in 5.5 seconds. Averaging 77 meters per second or 150 knots.

I'd say that's closer to 5.6 seconds, or your distance is ~6m off? making it 147kt average. But yeah, they're accelerating from ~141kt to ~152kt on that bit of runway. (how did you figure the distances? could be my data being off)

Do you know Vr?

RAT 5

19th Oct 2017, 14:15

.Scott: Well done. A career in AAIB awaits. Keep us posted.

parabellum

19th Oct 2017, 21:36

.Scott:
In this case, I am looking at the shadow of the wing to judge the relative position of the 737 at it crosses runway landmarks.

Surely, before any information from shadows can be included you must know the height of the sun above the horizon, its position relative to the aircraft etc. also, just minor movement of the hand holding the smartphone will change the picture. Throughout this thread assumptions have been made without knowing any of the relevant trigonometry which has just been ignored.

wiedehopf

19th Oct 2017, 22:04

So i had some snarky remarks but i'll cut it out.
How many meters would you guess is the shadow from the wing? If you say less than 10 than that's easily good enough to know where the airplane is.
He only used the shadow to get relative positions so speeds estimated are as accurate as possible. The change of sun angle during takeoff is negligible.
Regarding the angle described in an earlier post, there is some distortion but the analysis isn't nearly as bad as you make it out to be.

Instead of just disregarding what they did maybe use some trigonometry to approximate the errors made using their techniques.

roving

19th Oct 2017, 22:09

Does this help?

DaveReidUK

19th Oct 2017, 22:15

Surely, before any information from shadows can be included you must know the height of the sun above the horizon, its position relative to the aircraft etc. also, just minor movement of the hand holding the smartphone will change the picture. Throughout this thread assumptions have been made without knowing any of the relevant trigonometry which has just been ignored.

Actually the trigonometry isn't complicated at all, particularly given some reasonable assumptions, such as:

a) the aircraft tracking more-or-less along the runway centreline up to the point where it rotates and becomes airborne, and

b) the sun staying in the same position in the sky for the duration of the takeoff roll :O

The point at which the aircraft rotates and becomes airborne can be readily discerned from the change in the angle that the wing L/E subtends with the horizon, the position of the wingtip/winglet relative to the runway edge marking and the distance between a point on the wing and its corresponding shadow on the runway.

Minor movements of the camera will have a negligible effect on any of those.

CappyJax

20th Oct 2017, 00:48

I see the aircraft rotate right after the 1,000 marker, and it seems like a very mild rotation. Some pilots rotate like an aerobatic maneuver, and others do it like they are taking a child's hand. I am guessing this pilot is the latter.

framer

20th Oct 2017, 04:23

Well, if the pilot rotated at Vr at a rate of one degree per second, he or she would have chewed up a lot f runway before the wheels lifted compared to a normal flight where the rotation rate is approx 2.5 degrees per second.
Rough figures, at 150kts you're using 250ft of runway a second.
The aircraft leaves the ground at about 11 degrees nose up.
At the normal rotation rate it is 4.4 seconds from beginning the rotation until airborne.
At 1 degree per sec it is 11 seconds.
That's an extra 6.6 seconds on the ground with the slower rate.
6.6 seconds = approx 1600ft of extra runway used.
Kinda explains everything really ( assuming the estimated rotation rate is correct).

Edit; I just had a look in the FCOM and lift off at flap 5 is 8 degrees, not 11, so the slower rate uses an extra 1200ft of runway, not 1600ft.

neila83

20th Oct 2017, 04:24

RatherBeFlying

20th Oct 2017, 06:43

The formula for constant acceleration is v = 2 * d/t - final velocity is twice the average I can agree with v = d/t yielding average velocity.

However acceleration during a jet takeoff is not constant as thrust from a jet increases non linearly as speed increases. Drag generally does not offset thrust increase while on the runway during takeoff.

As for shadow angle from the wing, corrections could be applied for earth rotation and latitude-longitude change as well as wing flex. Note that on the runway the sun is lined up close to the wing axis. The wing tip shadow stays in a constant relative position to the outer flap canoe until liftoff. A beer says any correction would be less than 10 cm. Etkin in Dynamics of Atmospheric Flight states that earth rotation and latitude-longitude change effects are negligible until in high mach flight.

Like the original poster I have had a similar view of the opposite end piano keys departing on a hot day and still wonder how things would have turned out had we had a V1 cut.

parabellum

20th Oct 2017, 08:40

LLuCCiFeR

20th Oct 2017, 09:49

Isn't there supposed to be a 35' screen height on a dry runway?

CL300

20th Oct 2017, 10:09

Only one question here : What is the screen height at the end of TODA on a wet runway ?
Does he comply with it ?

next question please ?

roving

20th Oct 2017, 10:34

The next question is that given that the runway was dry, what relevance does the screen height of 15 feet for wet runways have to do with the issue raised here?

That would be akin to saying that because emergency vehicles in the UK are exceptionally permitted to disregard the normal traffic rules when responding to an emergency providing the blue flashing lights and sirens are used, drivers of such vehicles could rely on that exception when not responding to an emergency.

Musician

20th Oct 2017, 10:35

The cameraperson is on their seat with a seatbelt on, so given the distances involved, camera movement is sure to be neglible - and the window size restricts the possible viewpoint variation even further. I did assume the aircraft staying on the centerline. The height of the observer can be judged by the height of the horizon with respect to the runway, as long as the airplane remains above the center.

The horizon isn't always visible (obscured by scenery and a small elevation), so I judged rotation by comparing it with the angle of the runway edge, which remains unchanged as the airplane is on the ground, but may vary as the plane lifts off, due to perspective and lens distortion. I've now confirmed the value of 6° rotation over the threshold by attempting to line up the horizon, see attached image. (Lining the first image up by the edge of the green or the treetops, the difference is about 0.3°.)

Takeoff was 1:30, I believe, so on BST the sun should be almost to the south, on a takeoff due west. That means the shadow position changes minimally with wing height over the runway (the point of contention being that the plane is low over the threshold); 10' height change with the sun 12° off-axis equals 2' lateral position change (sun 191°az 29°el (http://www.sunposition.info/sunposition/spc/locations.php) at 1:30 BST). The shadow shape will narrow <1% as the wing rotates 6°.

I've looked at the distance from the blue dot at the bottom of the wingtip to the tip of the wing shadow to determine wingtip height. Assuming[1] the bottom of the winglet is at 13.5' over the eastern threshold marker, it rises as the wing flexes with lift and is around 15' over the center of the runway, up to the aiming point. Rising slowly (~60 ft/min), it exceeds 17' at the final touchdown marker and shows from 19 to 20.5 feet over the threshold marker (~300 ft/min). Runway end 22.5', 400'/min. This checks with the wingtip positions on the image I posted at #192 (http://www.pprune.org/rumours-news/600731-ryanair-uses-all-runway-10.html#post9929200).

I believe that takes care of Dave's suggestions (thank you!).

[1] http://www.boeing.com/assets/pdf/commercial/airports/acaps/737.pdf p.46 (p.50 in the PDF), row K.

.Scott

20th Oct 2017, 12:56

.Scott:
Surely, before any information from shadows can be included you must know the height of the sun above the horizon, its position relative to the aircraft etc. also, just minor movement of the hand holding the smartphone will change the picture. Throughout this thread assumptions have been made without knowing any of the relevant trigonometry which has just been ignored.
I only need to know that the shadow remains at the same relative position to the plane - within a meter or two.

Of course, you may want to know distance from the end of the runway to a particular spot on the plane - such as the nose or the landing gear. And I do not have those offsets.

As other posters have noted, since the sun angle does not appreciably change during the take off roll, and the wing stays approximately the same distance above the surface during that time, the shadow makes for a good indicator. It is moving with the plane.

As far as the distances are concerned: I used a runway map, compared it to photographs of the airport to verify that it was true, downloaded it to my computer, brought it up in paint, and examined it at the pixel level.

Then I used the 2011 meters and the runway end markers to establish the exact scale. All other measurements were based on that.

Perhaps the biggest contributor to error was the timings. If I had downloaded the video, I could have stepped through it frame by frame and gotten timing good to about 70 milliseconds. But since I viewed them from the web, those timing were probably only good to about 200 ms.

DaveReidUK

20th Oct 2017, 13:19

Fair enough all you naysayers, wiedehof, neila83/David Reid, yet more assumption without a single figure of data to back it up, just your own guess work, take it all to an enquiry, or a court if you like, and see how far you get

I listed my two assumptions (that the aircraft steered straight down the runway, and that the sun didn't move over those 45 seconds).

Could you clarify which one you think is unwarranted, please ? :ugh:

CL300

20th Oct 2017, 15:11

The next question is that given that the runway was dry, what relevance does the screen height of 15 feet for wet runways have to do with the issue raised here?

ok make it dry then.. and ?

What is the measured height at the en of TODA ?

roving

20th Oct 2017, 15:40

Here is a thread where that question was debated at length.

http://www.pprune.org/tech-log/592990-screen-height-35ft-where.html

scifi

20th Oct 2017, 16:16

As the runway slopes downwards at Bristol, I think it is more accurate to say that Bristol took the runway away from the airplane, and not vice-versa.
Similar to this....

https://www.youtube.com/watch?v=ne9JvLeLA7A

.

Herod

20th Oct 2017, 16:31

Isn't this all getting a bit silly? I think we can take it that the aircraft has passed V1, therefore the stop scenario doesn't apply. It's probably past Vr as well, and still accelerating, so in the case of an engine failure has kinetic energy beyond that required at Vr. Yes, it was a late and slow rotate, for whatever reason, but not dangerous, and certainly not warranting the analysis going on here. Then, what do I know? I'm just a retired airframe driver. Ask the crew.

roving

20th Oct 2017, 16:54

Ask the crew.

My impression is that that is what some would like to do.

EGLD

20th Oct 2017, 18:46

(Writing solely as a passenger: I am not an airline pilot)

If you've ever been on a 747 taking off from Johannesburg to Europe, a 60+ second take-off roll was standard. But then it's at 5,500' altitude and flying distance to London is 5,600 miles/9,000km. Runway 03L in JHB is 4,400 metres/14,000 ft long.

try it in an a340 :eek:
:mad:

Musician

21st Oct 2017, 00:00

According to their license (https://www.caa.co.uk/uploadedFiles/CAA/Content/Standard_Content/Commercial_industry/Airports/Aerodrome_licences/Files/EASA%20aerodrome%20certificates.pdf), TODA at Bristol is at 3016m, a full 1005m past the end of runway 27-you'll easily make 35' with an angle of ascent of only 0.6°. 10 seconds at 200kt with a vertical speed of 250 ft/min will also do it.

The plane is passing over an approach light at 2 seconds (60 frames) after it passes the runway end.

As far as the distances are concerned: I used a runway map, compared it to photographs of the airport to verify that it was true, downloaded it to my computer, brought it up in paint, and examined it at the pixel level.

Then I used the 2011 meters and the runway end markers to establish the exact scale. All other measurements were based on that.I used a similar procedure. Where did you find your runway map? I had trouble getting the 2011m to match; my scale may have been off, but I concluded that it was the length of the whole tarmac, minus *one* of the small bits on the end (beyond the taxiway). (This source (https://airportguide.com/airport/runway/BRS) has the runway at 2027m.) But that may have been a measuring error -- though the taxiway entrance distances seemed to match up with the given TORAs. I was also assuming the markings are metric, in multiples of 5m, which may not be true.

Stepping through the downloaded video frame by frame still has some timing error as some frames are duplicated; and you need to estimate fractional frames if you want to be really accurate about speed determinations. The shadow method's accuracy suffers from the fact that the wing ends seem to oscillate up and down by about half a foot.

P.S.: The LDA for rwy 27 is 1881m. Counting my pixels, the distance from the white stripe marking the displaced threshold to the end of the tarmac is 1882m, so I think my scale is correct. But the 1938m LDA for rwy 09 would be excluding the piano keys at the start and excluding the stub of tarmac beyond taxiway A.

Capt Fathom

21st Oct 2017, 04:56

I'm not convinced yet. I need to see more calculations and video analysis to prove that aircraft made it to its destination. Any videos of the arrival? :E

Odins Raven

21st Oct 2017, 08:49

Has anyone actually verified the date of the video?

If it was windy and the crew applied Boeing’s winshear technique they can delay rotation to calculated Vr+20, or Vr equivalent to RTOW whichever is lower. This is to account for wind shear encounters on rotation.

The “latest 2000’ before runway end” applies to wind shear encountered during the takeoff roll.

How do we know this isn’t what the crew were doing on this day? BTW I’m not a RYR apologist before someone mentions that.

Colours389

21st Oct 2017, 09:21

Reading the YouTube post the flight appears to be 25th July at approx 8:15. From the data I can find, conditions appears to be: -

8:20 AM

Temp 17.0 °C
Dew point 14.0 °C
RH 82%
Pressure 1018 hPa
Visibility 10.0 km
Wind dir Variable
Speed 5.6 km/h / 1.5 m/s
Gust speed -
Precip N/A
Events Unknown
Conditions Clear

Meikleour

21st Oct 2017, 09:29

Why are people discussing screen heights which are applicable to one engine out performance when patently both engines were operating in this case?

Stan Woolley

21st Oct 2017, 10:53

Meikleour

21st Oct 2017, 12:01

I-FORD: We all know that! The point that you seem to have avoided is that the performance on a normal take-off should vastly exceed the minimum requirements!
This would appear not to be the case with this video. What needs to be asked is "why was the rotation so late and/or so slow?"

Meikleour

21st Oct 2017, 12:55

I-FORD:"Late or slow rotation doesn't mean unsafe when you have 1000mt of clearway in front of you"

I think you might find that statement would be disputed by the aircraft manufactures. In fact thay all go out of their way to describe the correct techniques required to realise the required performance profile. What if the take-off is obstacle limited? Still no problem?
Every incident report that I have read where aircraft have been shown to have had "near misses" with respect to performance on take-off have proved to have errors in performance calculations, data entry errors or handling errors. You seem to have a handle on this being a normal take-off and therefore nothing need be investigated?

kungfu panda

21st Oct 2017, 12:57

This is about the third or fourth time going through this.

Firstly: 35' at the end of the clearway is only relevant to an engine failure scenario. You should be much higher than that with two engines operating.

Secondly: If they'd had an engine failure at or just prior to V1 it looks unlikely they could have stopped. If they'd had an Engine failure approaching the threshold, it looks unlikely that they could have made a safe takeoff.

Thirdly: Boeing say in the Training manual that an aircraft on a normal takeoff should easily achieve a height 150' at the opposite end of the runway. On this basis alone, this was not a normal takeoff according to the aircraft manufacturer.

DaveReidUK

21st Oct 2017, 13:24

Herod, it's way past silly!

On the contrary - it's become a fascinating insight into different pilots' understanding of performance rules that one would have hoped had been written sufficiently unambiguously as to not be subject to interpretation. :O

KelvinD

21st Oct 2017, 13:50

One factor that, if taken into account, renders a lot of the above arguments pointless.
I bet you that both the people in the driving seats had plans to get home safe and sound, no doubt with plans for dinner with the family etc.
Incidentally, last nights' HIGNFY had the following comment re storm Ophelia: "It was so windy, A Ryanair flight became airborne"!

kungfu panda

21st Oct 2017, 14:33

Nope, try reading the definition of Take Off Distance

Not knowing their V1 and where it was attained we have no clue about it

You (and others) seem to miss the fact that the end of the TODA was more than 1000mt from their lift-off point.

I have read the definition of take off distance. Now you re-read it. It refers to Engine failure at V1.

I agree that we don't know the position on the runaway that they achieved V1 and agree that looking at the video, it's speculation that stopping would not have been possible from minimum V1. However on a dry runway V1 normally approximates Vr.If they rotated at Vr. They certainly could not have stopped from any point within the previous 500' of where they started the rotation.

Boeing clearly says that during a normal takeoff 150' is easily achieved by the opposite end of the runway. It has been referenced in previous posts on this thread. It's in the Boeing training manual.

My opinion is that sadly there is a serious lack of professionalism by some who suggest that this was a normal take off.

Stan Woolley

21st Oct 2017, 14:48

On the contrary - it's become a fascinating insight into different pilots' understanding of performance rules that one would have hoped had been written sufficiently unambiguously as to not be subject to interpretation.

You mean it's a way to show off how much (or how little) you know about 'aeroplanes'. Ego massaging imho.

If we all had our flights minutely investigated by the peanut gallery I'm sure that we would find that every one of us had done something that appeared questionable. If the video had been of a BA aeroplane, do you think the vultures would have been circling the same way?

kungfu panda

21st Oct 2017, 15:00

I think that if it was BA then there would be a lot more criticism and almost certainly an investigation. In my opinion Ryanair get away with more than almost any other Airline.
If this happened in China, believe me, the CAAC would be all over it. If it were expat Pilots they would have their CAAC license revoked with immediate effect.

Stan Woolley

21st Oct 2017, 15:17

I think that if it was BA then there would be a lot more criticism and almost certainly an investigation. In my opinion Ryanair get away with more than almost any other Airline.

I totally disagree with your first assertion. In fact it's laughable.

How can you say such a thing? Oh yeah, it's 'your opinion'. Have you ever flown for them?

If this happened in China, believe me, the CAAC would be all over it. If it were expat Pilots they would have their CAAC license revoked with immediate effect.

So is that what you think should happen?
Thank goodness you're not in a position of authority, possibly you are? :hmm: Assuming that something was perhaps amiss, what happened to 'proper investigation'? That's the problem, too many Quick draw McGraw's, not enough level heads these days.

kungfu panda

21st Oct 2017, 15:31

CL300

21st Oct 2017, 15:39

Well, they got airborne before TORA no ? I do not have the charts but what is TODA on this runway ? and ASDA ?

I was pushing on the 15ft and the 35 ft because very often this justification is coming into play when it gets a but "murky"

But may be there is more data then a shadow and a couple of videos ? alas ! Am I stupid this is pprune !!!!

Stan Woolley

21st Oct 2017, 16:06

Regarding my point about China. It's absolutely not the way I would like to see things handled. I do believe that it was an error caused systemically. I would like a non punitive investigation in order to resolve the error.

That's good to hear. ;)

I do believe that Ryanair get away with murder and I do believe that the only true oversight of Ryanair is the Media and indeed this forum. Having seen interviews with MOL, I even think that the media are astonishingly weak in front of him.

What evidence do you have to make such an assertion? I have worked for a few airlines, including some well regarded ones, and Ryanair runs (or at least used to run) a very tight ship when it comes to flight ops.

I have experienced gash, but certainly not during my time with Ryanair.

911slf

21st Oct 2017, 16:20

There seems to be a range of opinions from "nothing to see - move along" through to "this warrants a formal investigation". How does one distinguish between "barely acceptable" and "good" flying skills - especially in airline service as distinct from in the simulator?

Are there objective measures?

What would you do about a "good" pilot who on one/two/three occasions falls far below normal standards?

Would a "barely acceptable" pilot eventually be considered for a command course so long as his/her performance never fell to "unacceptable"?

Wee Weasley Welshman

21st Oct 2017, 17:12

That’s ‘my’ runway and I’ve been as hot and heavy on it as it’s possible to be in 17 years of Ops. I’ve never rotated there. If I had I would have needed new trousers for the next days report.

fireflybob

21st Oct 2017, 17:38

I have experienced gash, but certainly not during my time with Ryanair.

Stan Wooley, I would certainly second your comments here.

Musician

21st Oct 2017, 20:23

I have read the definition of take off distance. Now you re-read it. It refers to Engine failure at V1.

I agree that we don't know the position on the runaway that they achieved V1 and agree that looking at the video, it's speculation that stopping would not have been possible from minimum V1. However on a dry runway V1 normally approximates Vr.If they rotated at Vr. They certainly could not have stopped from any point within the previous 500' of where they started the rotation.
I believe the aircraft started to rotate at the touchdown marker before the aiming point, that would be 480m/1600ft from the end of the runway, at a very approximate 146kt. Going back to 500' before that, i.e. to the previous touchdown marker, the plane was at approximately 141 kt. Does it seem unlikely to you that V1 and Vr differ by 5kt on a derated takeoff?

35' is basically the height where the plane enters the "takeoff flight path" that maintains 35' obstacle clearance; obviously you can't do that at a lower height. TOD is computed such that the plane can reach that height with 15% spare distance on all engines, and can reach it with one engine inoperable from V1 and Vr. Clearway is limited to half the runway length by regulation.

The more interesting definition is for TOR: FAR 121.189 or 135.379 prescribe that "(3) The takeoff run must not be greater than the length of the runway." With FAR 25.113,
If the takeoff distance includes a clearway—

(1) The takeoff run on a dry runway is the greater of—

(i) The horizontal distance along the takeoff path from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, as determined under §25.111 for a dry runway; or

(ii) 115 percent of the horizontal distance along the takeoff path, with all engines operating, from the start of the takeoff to a point equidistant between the point at which VLOF is reached and the point at which the airplane is 35 feet above the takeoff surface, determined by a procedure consistent with §25.111.
"VLOF is the calibrated airspeed at which the airplane first becomes airborne." So basically, the aircraft must achieve 35' within the same distance past the runway end that it achieved liftoff prior to the runway end. If that distance is 600ft, as this departure probably exceeded, a 5% / 3.5° angle of ascent would suffice. So that seems within margins as well.

P.S.: There is a safety consideration, though. I found an article in an old BOING AERO issue (http://www.boeing.com/commercial/aeromagazine/articles/qtr_02_09/article_04_1.html) with a nice infographic down the page that shows that a 737 usually lifts off at 7°-9° attitude, and that this should be reached 3 seconds after Vr. If you rotate more slowly, a higher liftoff speed could result, and that might lead to a tire overspeed event.

P.P.S.: Pilot Guide to Takeoff Safety (https://www.faa.gov/other_visit/aviation_industry/airline_operators/training/media/takeoff_safety.pdf) (2007): "Roughly 15% of the RTO accidents of the past were the result of improper preflight planning."
"The use of clearway to increase takeoff weight “unbalances the runway” and results in a lower V1 speed."

P.P.P.S.: I should probably amend my above calculations to account for the 15% margin for all-engine operation; this effectively shortens the allowable runway use by 13%, that's 260m in case of Bristol. Since the aircraft was not at 35' at the actual runway end, liftoff needed to be at least 520m (1730') prior to the runway end for the end of the takeoff run, to allow for the 15% extension and not exceed the actual runway length (TORA). I believe that this was not the case here, since I have previously figured that liftoff did not occur before the plane reached the aiming point.