Ryanair uses all the runway.
Prober, that makes sense.
When I go flying at work, I try to execute things under my control by SOP. Amongst other things that means taking off with the correct thrust and flap settings from the right place on the runway (and the right runway).
It also means rotating at the right rate from the right speed; I have to say that due to the vagaries of trim, different airframes and environmental conditions there is a certain spread to my efforts and those of my partner-in-crime on the day.
As to the effects? Well, Boeing FCTMs carry interesting diagrams showing slow and under rotation and the difference to 35’, which can be quite noticeable. Both errors cause the the takeoff flight path to be lower, which is undesirable and to be avoided (just to be clear) but not necessarily much more dangerous than normal in the way you might expect just by looking at it from the side.
If the power setting was correct, then stopping from <V1 should be assured. In the event of a thrust loss at V1, the general technique is a slower rotation to a lower pitch attitude - as the acceleration is less from that point there is more time to get it right, plus there might be a little more concentration from all parties.
Past V1 without a failure, in energy terms you are rising above the OEI flightpath with every second that you have AEO. Should you experience a thrust loss when airborne, you will be at V2+ and most likely getting a better climb gradient.
TL;DR: An improper (slow) rotation reduces margins but unless it’s so slow you don’t leave the ground, it’s unlikely to cause an issue, even with a subsequent engine failure. However, you should always aim to follow FCTM guidance as closely as possible (has to be said).
When I go flying at work, I try to execute things under my control by SOP. Amongst other things that means taking off with the correct thrust and flap settings from the right place on the runway (and the right runway).
It also means rotating at the right rate from the right speed; I have to say that due to the vagaries of trim, different airframes and environmental conditions there is a certain spread to my efforts and those of my partner-in-crime on the day.
As to the effects? Well, Boeing FCTMs carry interesting diagrams showing slow and under rotation and the difference to 35’, which can be quite noticeable. Both errors cause the the takeoff flight path to be lower, which is undesirable and to be avoided (just to be clear) but not necessarily much more dangerous than normal in the way you might expect just by looking at it from the side.
If the power setting was correct, then stopping from <V1 should be assured. In the event of a thrust loss at V1, the general technique is a slower rotation to a lower pitch attitude - as the acceleration is less from that point there is more time to get it right, plus there might be a little more concentration from all parties.
Past V1 without a failure, in energy terms you are rising above the OEI flightpath with every second that you have AEO. Should you experience a thrust loss when airborne, you will be at V2+ and most likely getting a better climb gradient.
TL;DR: An improper (slow) rotation reduces margins but unless it’s so slow you don’t leave the ground, it’s unlikely to cause an issue, even with a subsequent engine failure. However, you should always aim to follow FCTM guidance as closely as possible (has to be said).
The other side of the slow rotation is that the 738 is prone to tailstrikes, and Ryanair hammer tailstrike awareness in cadets, leading some to err on the slow side of the recommended rotation rate.
I recall RYR training material emphasising 2°/sec where the FCTM states 2-3°/sec with rates slower in longer aircraft. If you are targeting 2°/sec and you undershoot it’s easy to eat a lot of runway. The NG rotation also tends to “stick” at 8-10°NU as the tail enters ground effect.
I recall RYR training material emphasising 2°/sec where the FCTM states 2-3°/sec with rates slower in longer aircraft. If you are targeting 2°/sec and you undershoot it’s easy to eat a lot of runway. The NG rotation also tends to “stick” at 8-10°NU as the tail enters ground effect.
This is a gas thread.
TORA is Take-Off Run Available. That means the physical distance of paved runway.
TODA is Take-Off Distance Available. That distance includes TORA plus any published Clearway.
Clearway can be used for take-off perf calculations to attain your 35' Screen Height (Dry).
Yes, it looked unusual. It liked tight. But without a shadow of a doubt, they made 35' by the end of the TODA.
With the way Rwy 27 is, you can bet they had a large V1 to Vr split. But once they had an engine failure at V1, they'd be using all the available TORA remaining to accelerate to Vr and then use the Clearway to get to Screen Height.
Most runways aren't 2000m anymore. Coupled that with the unusual slope characteristics of Runway 27 and 1000m of Clearway and you'll get that type of take-off we see in the video.
My post history will show I hate all things Ryanair. But this is bordering on the ridiculous at this stage.
TORA is Take-Off Run Available. That means the physical distance of paved runway.
TODA is Take-Off Distance Available. That distance includes TORA plus any published Clearway.
Clearway can be used for take-off perf calculations to attain your 35' Screen Height (Dry).
Yes, it looked unusual. It liked tight. But without a shadow of a doubt, they made 35' by the end of the TODA.
With the way Rwy 27 is, you can bet they had a large V1 to Vr split. But once they had an engine failure at V1, they'd be using all the available TORA remaining to accelerate to Vr and then use the Clearway to get to Screen Height.
Most runways aren't 2000m anymore. Coupled that with the unusual slope characteristics of Runway 27 and 1000m of Clearway and you'll get that type of take-off we see in the video.
My post history will show I hate all things Ryanair. But this is bordering on the ridiculous at this stage.
A Clearway aids/permits heavier aircraft to use shorter runways that otherwise wouldn't have been allowed, performance wise.
If there was no Clearway at Bristol, Rwy 27, that Ryanair flight would either be pax limited commercially (like BHD) or have to do a tech stop en-route.
I understand from a previous poster this flight was off to the Canaries? Full load?
If that's the case, I can absolutely see how the wheels maybe, apparently, just left the paved surface at the very end. It's the very existence of the 1000m Clearway that allowed them to do it the way we saw in the video.
There was nothing illegal/dangerous/crew error/etc etc about this.
I hope the people writing that this take-off was clearly abnormal are not commercial pilots. Your perf and your knowledge and understanding of it is your bread & butter of flying. On a par with pitch & power. It is absolutely the fundamental thing keeping you alive.
How does one go about closing a thread?
If there was no Clearway at Bristol, Rwy 27, that Ryanair flight would either be pax limited commercially (like BHD) or have to do a tech stop en-route.
I understand from a previous poster this flight was off to the Canaries? Full load?
If that's the case, I can absolutely see how the wheels maybe, apparently, just left the paved surface at the very end. It's the very existence of the 1000m Clearway that allowed them to do it the way we saw in the video.
There was nothing illegal/dangerous/crew error/etc etc about this.
I hope the people writing that this take-off was clearly abnormal are not commercial pilots. Your perf and your knowledge and understanding of it is your bread & butter of flying. On a par with pitch & power. It is absolutely the fundamental thing keeping you alive.
How does one go about closing a thread?
I understand from a previous poster this flight was off to the Canaries? Full load?
If anyone wants to know the ramifications of clearway then fill your boots here!
Clearway
Ok, fair enough. But then I'd be asking did they tanker round trip etc.
The key to this whole thread though is the fact there is 1000m of Clearway on Rwy 27 that permit the aircraft to basically, how should I put it, scrape off the runway like we saw in the video.
It's all legal etc, regardless of how it looks.
Anyway.
The key to this whole thread though is the fact there is 1000m of Clearway on Rwy 27 that permit the aircraft to basically, how should I put it, scrape off the runway like we saw in the video.
It's all legal etc, regardless of how it looks.
Anyway.
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Sprite, where were you earlier in the thread ? Could have stopped all the ensuing rubbish a lot earlier but it was quite entertaining, in parts. By the way, very neatly articulated.
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Description
In aviation, clearway is a term related to the dimension of some runways and it is abbreviated with CWY. A clearway is an area beyond the paved runway, free of obstructions and under the control of the airport authorities. The length of the clearway may be included in the length of the takeoff distance available (TODA). For example, if a paved runway is 2000 m long and there are 400 m of clearway beyond the end of the runway, the takeoff distance available is 2400 m long.
I venture to suggest that for an area to qualify as a "clearway" it has to meet the ordinary meaning of that word, i.e. a way which is clear and unobstructed. As appears from Google maps, in the direction of takeoff on RWY 27 there is indeed a clear and unobstructed area of grassland beyond the runway that appears to meet the description of a clearway. Once the lights/fence/road is reached it is no longer a "clearway' because it is obstructed.
Does that area of grassland stretch 1000 metres beyond the runway?
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I venture to suggest that for an area to qualify as a "clearway" it has to meet the ordinary meaning of that word, i.e. a way which is clear and unobstructed. As appears
The lower limit of a clearway is defined by a slope angle (ISTR 1 in 60 but ICBW) which assumes a minimal angle of climb. Bristol is on a hill and the ground beyond 27 falls away rapidly. All you need to do is clear the ILS antennas.
from Google maps, in the direction of takeoff on RWY 27 there is indeed a clear and unobstructed area of grassland beyond the runway that appears to meet the description of a clearway. Once the lights/fence/road is reached it is no longer a "clearway' because it is obstructed.
Does that area of grassland stretch 1000 metres beyond the runway?
Does that area of grassland stretch 1000 metres beyond the runway?
Hah! To be honest, I've been following it from the start and thought it'd be quickly ended by someone else so didn't bother writing. I guess 14 pages is my limit!
Only half a speed-brake
I agree in general with sprite1 that what we see is just a distance-limited take off, at the edge of calculated figures. It's not a common occurence and thus looks scary a bit. The video shows them get airborne about 300 m before runway end, all good. Maybe with a small tailwind blow around Vr.
This however needs to be tweaked, for the sake of completeness.
Accelerate to Vr, then pitch up to the unstick attitude and the aircraft gets airborne dozens meters further, at Vlf. From the lift-off, the trajectory continues until 35' height still accelerating to reach V2 concurrently. Now, the geometrical half-way point (equidistant) between getting airborne at Vlf and 35' with V2 must be still inside the paved and designated TORA (TOR<=TORA). That would be applicable for dry runway take-off with 1 ENG inop on a twin, derived from TOR definition JAR 25.113 Subpart B.
Post intended solely as an expansion of what sprite1 contributed above.
Accelerate to Vr, then pitch up to the unstick attitude and the aircraft gets airborne dozens meters further, at Vlf. From the lift-off, the trajectory continues until 35' height still accelerating to reach V2 concurrently. Now, the geometrical half-way point (equidistant) between getting airborne at Vlf and 35' with V2 must be still inside the paved and designated TORA (TOR<=TORA). That would be applicable for dry runway take-off with 1 ENG inop on a twin, derived from TOR definition JAR 25.113 Subpart B.
Post intended solely as an expansion of what sprite1 contributed above.
Last edited by FlightDetent; 29th Oct 2017 at 22:30.
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Accelerate to Vr, then pitch up to the unstick attitude and the aircraft gets airborne dozens meters further, at Vlf. From the lift-off, the trajectory continues until 35' height still accelerating to reach V2 concurrently. Now, the geometrical half-way point (equidistant) between getting airborne at Vlf and 35' with V2 must be still inside the paved and designated TORA (TOR<=TORA). That would be applicable for dry runway take-off with 1 ENG inop on a twin, derived from TOR definition JAR 25.113 Subpart B.
P.S.: JAR 25.113 is CS 25.113 now. It still says the same as FAR 25.113.
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)
The other side of the slow rotation is that the 738 is prone to tailstrikes, and Ryanair hammer tailstrike awareness in cadets, leading some to err on the slow side of the recommended rotation rate.
I recall RYR training material emphasising 2°/sec where the FCTM states 2-3°/sec with rates slower in longer aircraft. If you are targeting 2°/sec and you undershoot it’s easy to eat a lot of runway. The NG rotation also tends to “stick” at 8-10°NU as the tail enters ground effect.
I recall RYR training material emphasising 2°/sec where the FCTM states 2-3°/sec with rates slower in longer aircraft. If you are targeting 2°/sec and you undershoot it’s easy to eat a lot of runway. The NG rotation also tends to “stick” at 8-10°NU as the tail enters ground effect.
Only half a speed-brake
@musician: Correct. You are referring to all engine case with +15% margin, which I had purposefully avoided. Only tried to put more detail to spirte1's: lose an engine - use all remaining tarmac to rotate.
