Manual Calculation for TO Pitch Attitude Target
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Manual Calculation for TO Pitch Attitude Target
Was reading an old thread about a 747 accident and came across this interesting quote.....
"During rotation you normally aim for about 15 degr pitch attitude, and as soon as you get airborne follow the FD and shoot for V2 +10.
Initial pitch attitude out of a field elevation of ±5000' with this kind of weight (and derated) would be around 13 degr I would guess. With a full rated TO it would be higher, then the 16-17 degr you mention could be right. Perhaps they don't use derated TO's for safety reasons there, I don't know. I've never been there and wouldn't mind if it stayed that way. On the Classic we used to calculate the initial pitch attitude, but on the -400 you just go for 15 degr and then follow the FD."
I have ever heard of an aircraft where the initial pitch attitude was manually calculated. Has anyone else seen this on other aircraft?
"During rotation you normally aim for about 15 degr pitch attitude, and as soon as you get airborne follow the FD and shoot for V2 +10.
Initial pitch attitude out of a field elevation of ±5000' with this kind of weight (and derated) would be around 13 degr I would guess. With a full rated TO it would be higher, then the 16-17 degr you mention could be right. Perhaps they don't use derated TO's for safety reasons there, I don't know. I've never been there and wouldn't mind if it stayed that way. On the Classic we used to calculate the initial pitch attitude, but on the -400 you just go for 15 degr and then follow the FD."
I have ever heard of an aircraft where the initial pitch attitude was manually calculated. Has anyone else seen this on other aircraft?
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Never seen it on the 777, but as one of the first modern jets not to require “3 degrees per second”, this is not surprising.
An initial target pitch would only be valid for a specific Vr, rotation rate, and 'standard power’.
1) Having experienced close to 5 degrees/second and less than 2, from the same runway with similar weights, the final 'correct' pitch was very different.
2) What is standard power? Who knows, but the resulting acceleration will be a factor for the pitch target. Are you at max assumed temp, and lighter than normal?
Targetting a specific pitch for takeoff could well be a “children of the magenta line” problem in the making.
It's critical that Type Training includes the correct rotation technique, 'towards a target pitch', adjusted to achieve V2 + 15. The buffer of 15-25 assumed that you had excess energy, and that the climb gradient would not therefore be compromised.
An initial target pitch would only be valid for a specific Vr, rotation rate, and 'standard power’.
1) Having experienced close to 5 degrees/second and less than 2, from the same runway with similar weights, the final 'correct' pitch was very different.
2) What is standard power? Who knows, but the resulting acceleration will be a factor for the pitch target. Are you at max assumed temp, and lighter than normal?
Targetting a specific pitch for takeoff could well be a “children of the magenta line” problem in the making.
It's critical that Type Training includes the correct rotation technique, 'towards a target pitch', adjusted to achieve V2 + 15. The buffer of 15-25 assumed that you had excess energy, and that the climb gradient would not therefore be compromised.
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It sounds to me like we have a situation where…..for the same aircraft type(at least for certain types), some companies do a calculation(or whatever it may be called) for a target pitch attitude on rotation while others do not.
For those that so, is this a recommendation in the manufacturers manuals or a company procedure.
I am used to the target of 15 degrees and adjust as required.
For those that so, is this a recommendation in the manufacturers manuals or a company procedure.
I am used to the target of 15 degrees and adjust as required.
Last edited by punkalouver; 8th Mar 2022 at 19:47.
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Depends on company and type.
757 really needed information as it was anything up to 23 degrees NU at light weights. Everything was on the laminated check list at my operator - TOW versus target pitch.
737 rotation by time and then general pitch attitude and speed target, Significant change in rotation behaviour during rotation in the NG's as the tail pitched down into ground effect.
Rob
757 really needed information as it was anything up to 23 degrees NU at light weights. Everything was on the laminated check list at my operator - TOW versus target pitch.
737 rotation by time and then general pitch attitude and speed target, Significant change in rotation behaviour during rotation in the NG's as the tail pitched down into ground effect.
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It sounds to me like we have a situation where…..for the same aircraft type(at least for certain types), some companies do a calculation(or whatever it may be called) for a target pitch attitude on rotation while others do not.
For those that do……is this a recommendation in the manufacturers manuals or a company procedure.
I am used to the target of 15 degrees and adjust as required.
For those that do……is this a recommendation in the manufacturers manuals or a company procedure.
I am used to the target of 15 degrees and adjust as required.
The 767 had a large range of attitudes for takeoff - rule of thumb was 30 - GW in T gave a good target. Ie at MTOW of about 180T (kg) you aimed for 12 degrees nose up. At lighter domestic weights of say 120T you would aim for about 18 degrees nose up.
Last edited by ScepticalOptomist; 2nd Mar 2022 at 23:44.
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For the Boeing types I have flown 747/767/787 it was in the manufacturers manuals. A few types also generated a takeoff report via the printer giving stats on rotate rate, average pitch, maximum pitch, etc.
The 767 had a large range of attitudes for takeoff - rule of thumb was 30 - GW in T gave a good target. Ie at MTOW of about 180T (kg) you aimed for 12 degrees nose up. At lighter domestic weights of say 120T you would aim for about 18 degrees nose up.
The 767 had a large range of attitudes for takeoff - rule of thumb was 30 - GW in T gave a good target. Ie at MTOW of about 180T (kg) you aimed for 12 degrees nose up. At lighter domestic weights of say 120T you would aim for about 18 degrees nose up.
Last edited by punkalouver; 4th Mar 2022 at 04:08.
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Very interesting discussion. I’ve never heard of calculating a pitch attitude. Probably a big airplane thing, because they have a larger range of takeoff weights.
Interested to hear why the 777 doesn’t have a target rotation rate.
Interested to hear why the 777 doesn’t have a target rotation rate.
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Unfortunately, no examples provided from manufacturers manuals, other than a standard target pitch that is always the same, not calculated.
Which makes me suspect that this is a company initiated policy.
Which makes me suspect that this is a company initiated policy.
The 777 does have a target, it’s just not variable or calculated each take-off:
For optimum takeoff and initial climb performance, initiate a smooth continuous rotation at VR toward 15° of pitch attitude. However, takeoffs at low thrust setting (low excess energy) will result in a lower initial pitch attitude target to achieve the desired climb speed.
Also, on aircraft that use AT derates, fixed derates and improved climb, depending on the runway/flap/environment the AEO climb out pitch is spread over quite a wide band. As above, on the 777 we go towards 15degs with emphasis on towards while picking up speed trends and/or flight director commands during the latter part of the rotation. Fully derated on a long runway near sea level, 10degs is more like it but full-power off something short is nearer 20degs, possibly above.