Static takeoff vs rolling takeoff
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Static takeoff vs rolling takeoff
Hi,
Takeoff procedure 1: Engines at idle and brakes on. You release the brakes and then you advance the throttles to an intermediate thrust setting (40%N1 or 50%N1, EPR?). Once you reach this thrust on all engines, you apply takeoff thrust.
Takeoff procedure 2: With the brakes on and engines at idle you advance the throttles to an intermediate thrust setting. Once you reach this thrust on all engines, you release the brakes and then you apply takeoff thrust.
Are both takeoff procedures (1&2) considered static takeoff?
Reading from some posts, it seems the rolling takeoff is the recommended procedure. Is this true? Or is it up to the crew to decide between the rolling and the static takeoff?
Is it recommended to apply the 2 steps takeoff procedure (intermediate thrust: 40/50 N, then takeoff thrust) on both types of takeoff procedure?
When and how often the static takeoff is used (besides short runway)?
Feedback appreciated.
Takeoff procedure 1: Engines at idle and brakes on. You release the brakes and then you advance the throttles to an intermediate thrust setting (40%N1 or 50%N1, EPR?). Once you reach this thrust on all engines, you apply takeoff thrust.
Takeoff procedure 2: With the brakes on and engines at idle you advance the throttles to an intermediate thrust setting. Once you reach this thrust on all engines, you release the brakes and then you apply takeoff thrust.
Are both takeoff procedures (1&2) considered static takeoff?
Reading from some posts, it seems the rolling takeoff is the recommended procedure. Is this true? Or is it up to the crew to decide between the rolling and the static takeoff?
Is it recommended to apply the 2 steps takeoff procedure (intermediate thrust: 40/50 N, then takeoff thrust) on both types of takeoff procedure?
When and how often the static takeoff is used (besides short runway)?
Feedback appreciated.
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Rolling start Vs Standing start.
I consider your second procedure to be closer to a standing (static) start than procedure one. I know a standing start to be applying full power PRIOR to releasing the brakes. I do not like it as it is very abrupt and alarms the passengers. I prefer your procedure two if a standing(static) start is required.
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Each aircraft's AFM will describe the procedures to be used and any performance penalties required.
This is what Embraer say for the E-jets:
Note that using a normal take-off or rolling take-off technique requires a greater take-off distance.
This is what Embraer say for the E-jets:
Normal Takeoff up to 10 kt tailwind: Pilot lines up the airplane on the runway, applies brakes and adjusts thrust to 40% N1, when engines stabilize at 40% N1, releases brakes and advances thrust levers to TOGA detent.
NOTE: For normal takeoff with tailwind up to 10 kt, performance data is valid from the point where takeoff thrust (N1 target) is achieved.
Normal Takeoff with tailwind above 10 kt (If allowed by AFM):
Refer to TAIL WIND TAKEOFF of this section.
Static Takeoff: Pilot lines up the airplane on the runway, applies brakes, adjusts thrust to 40% N1, when engines stabilize at 40% N1, advances thrust levers to TOGA detent. Release the brakes when the takeoff thrust (N1 target) is achieved.
NOTE: Due to the possibility of compressor stall, a static takeoff is not recommended with a crosswind greater than 25 kt.
Rolling Takeoff: Pilot lines up the airplane with the centerline and, if cleared for takeoff, adjusts thrust Levers to 40% N1 without applying the brakes. When engines stabilize at 40% N1, pilot moves thrust levers to TOGA detent.
NOTE: For rolling takeoffs, performance data is valid from the point where takeoff thrust (N1 target) is achieved.
NOTE: For normal takeoff with tailwind up to 10 kt, performance data is valid from the point where takeoff thrust (N1 target) is achieved.
Normal Takeoff with tailwind above 10 kt (If allowed by AFM):
Refer to TAIL WIND TAKEOFF of this section.
Static Takeoff: Pilot lines up the airplane on the runway, applies brakes, adjusts thrust to 40% N1, when engines stabilize at 40% N1, advances thrust levers to TOGA detent. Release the brakes when the takeoff thrust (N1 target) is achieved.
NOTE: Due to the possibility of compressor stall, a static takeoff is not recommended with a crosswind greater than 25 kt.
Rolling Takeoff: Pilot lines up the airplane with the centerline and, if cleared for takeoff, adjusts thrust Levers to 40% N1 without applying the brakes. When engines stabilize at 40% N1, pilot moves thrust levers to TOGA detent.
NOTE: For rolling takeoffs, performance data is valid from the point where takeoff thrust (N1 target) is achieved.
Note that using a normal take-off or rolling take-off technique requires a greater take-off distance.
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Standing start Vs Rolling start.
For passenger comfort a rolling start is preferable. However some critical takeoffs mandate a standing(static) start. Anytime the brakes are released PRIOR to reaching target takeoff thrust you are doing a rolling start. The crew decides whether it will be a rolling or a standing start.
It is more advantageous, even on a short runway to do a rolling take off, the benefit of keeping your momentum going rather than having to accelerate from a dead stop is considerable in runway distance used.
Just don't hang about getting the thrust set, turn on as close to the beginning of the runway as you can while keeping it rolling, start carefully bringing the power up as you are lining up and have take off thrust set when you are aligned.
With this technique you already have considerable momentum with you and take off thrust set right at the beginning of the runway, best of both worlds.
Why would you want to stop and then have to reaccelerate all that mass ?
makes no sense.
Just don't hang about getting the thrust set, turn on as close to the beginning of the runway as you can while keeping it rolling, start carefully bringing the power up as you are lining up and have take off thrust set when you are aligned.
With this technique you already have considerable momentum with you and take off thrust set right at the beginning of the runway, best of both worlds.
Why would you want to stop and then have to reaccelerate all that mass ?
makes no sense.
Last edited by stilton; 21st Oct 2011 at 01:45.
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This is what I have in my B737-700 IGW FCOM Volume 1:
EW73
"A rolling takeoff is recommended for setting takeoff thrust. It
expedites takeoff and reduces risk of foreign object damage or
engine surge/stall due to a crosswind. The change in takeoff roll
due to the rolling takeoff procedure is negligible when compared to
a standing takeoff."expedites takeoff and reduces risk of foreign object damage or
engine surge/stall due to a crosswind. The change in takeoff roll
due to the rolling takeoff procedure is negligible when compared to
"Allowing the engines to stabilize for more than approximately 2
seconds prior to advancing thrust levers to takeoff thrust may
adversely affect rolling takeoff distance."seconds prior to advancing thrust levers to takeoff thrust may
EW73
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My experience on the 747/DC-8 is that a rolling takeoff, while spooling on the lineup, 90 degree turn to runway heading, is more advantageous. This procedure/technique also more easily mitigates a crosswind induced engine surge/compressor stall. No problems at all at runway limited weights.
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Nobody seems to have noticed that Stilton introduced the third type of Takeoff, i.e. The Roll-On Takeoff, where the aircraft commences the Takeoff with it's existing taxy speed. As Stilton suggests that it should be, it IS considered as equivalent to a Standing Start Takeoff, provided that the existing speed is at an approved minimum (usually 10 knots).
The Rolling Takeoff commences at Zero speed, and differs from the 'Roll-on' Takeoff in this respect. It IS approved (and usually recommended) provided that the Various Field Lengths are reduced by an approved amount (usually 60M or 200ft) before making the RTOW calculation. This can, in Field limited circumstances impose a significant reduction in RTOW, in the vicinity of 5% is not uncommon.
Best Regards,
Old Smokey
The Rolling Takeoff commences at Zero speed, and differs from the 'Roll-on' Takeoff in this respect. It IS approved (and usually recommended) provided that the Various Field Lengths are reduced by an approved amount (usually 60M or 200ft) before making the RTOW calculation. This can, in Field limited circumstances impose a significant reduction in RTOW, in the vicinity of 5% is not uncommon.
Best Regards,
Old Smokey
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Thank you for your feedback.
It seems we have 4 types of takeoff: 3 mentioned by FE Hoopy and one mentioned by Old Smokey.
Which type of takeoff is used for the takeoff performance charts or takeoff performance computations before flight?
Old Smokey, if I am not mistaken, you are saying that:
- A roll-on takeoff (with minimum 10 knots) is considered as equivalent to a standing takeoff
-The takeoff roll is increased (60m or 200ft) if the rolling takeoff is used.
But it seems that Boeing is saying there is negligible difference (less than 50ft) regarding the takeoff roll between the standing takeoff and the rolling takeoff. If this statement is true and the roll-on takeoff is considered as equivalent to the standing takeoff, therefore the difference in the takeoff roll between the rolling takeoff and the roll-on takeoff is negligible (less than 50ft).
If the difference is 50 ft, how much this distance will reduce the RTOW?
Feedback appreciated.
It seems we have 4 types of takeoff: 3 mentioned by FE Hoopy and one mentioned by Old Smokey.
Which type of takeoff is used for the takeoff performance charts or takeoff performance computations before flight?
Old Smokey, if I am not mistaken, you are saying that:
- A roll-on takeoff (with minimum 10 knots) is considered as equivalent to a standing takeoff
-The takeoff roll is increased (60m or 200ft) if the rolling takeoff is used.
But it seems that Boeing is saying there is negligible difference (less than 50ft) regarding the takeoff roll between the standing takeoff and the rolling takeoff. If this statement is true and the roll-on takeoff is considered as equivalent to the standing takeoff, therefore the difference in the takeoff roll between the rolling takeoff and the roll-on takeoff is negligible (less than 50ft).
If the difference is 50 ft, how much this distance will reduce the RTOW?
Feedback appreciated.
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Probably 1 of 2 most memorable takeoff's, Ferry flight departed Cambridge in an MD-11 from a MRO for Stansted, quite a short runway. Allmost a MPA standing T/O, felt the gear kick hard and rapid acceleration. I remember the crew flying just about blew innital altitude as we were allready lined up to land Shortest flight I have had, 9 minutes or so. I had the pleasure of sitting in the scribes seat, one hell of a birds eye view. The crew threw down the checklist on a just fly the damb plane basis.
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When I described the rolling takeoff, I categorized that as part of your "roll on" takeoff. Didn't realize a difference existed other than one turning and one not (and the two of them weren't considered really different by my airline). The option of either (or the three) was left to the Captain's discretion.
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AeroTech,
For the regulatory Authoroties that I have done Performance work for, a roll-on takeoff (with minimum 10 knots) is considered as equivalent to a standing takeoff
Beware that this might not be acceptable to all regulatory authorities (It was so in Australia for 3 types submitted to them). Douglas (in the pre-McD days allowed this for the DC9).
The takeoff roll increased (60m or 200ft) for the rolling takeoff was type specific for a Bombardier product that I did work for. It may differ for other aircraft. Essentially the 60M/200 ft penalty was the delta between Standing Start and Rolling Start total distance, the actual distance to achieve Full Takeoff thrust would exceed 60M/200 ft, but at this point, some reasonable speed would already exist.
Boeing's statement that there is negligible difference (less than 50ft) regarding the takeoff roll between the standing takeoff and the rolling takeoff is rather brave. If the takeoff is NOT Field limited, the penalty would be zero. If Field limited (particularly with a Tail-wind) the penalty can be up to 5% of RTOW (That's a 15000 Kg penalty for a B777-300ER).
All AFM scheduled performance is based upon the Standing Start, and that is what I provided when producing RTOWs. As The Rolling start is operationally preferred, I added an RTOW correction at the bottom of each column on RTOWs produced. As stated before, many times it was Zero (long runways), but up to 5% of RTOW when the Takeoff was Field limited (particularly in Tail-winds). In extreme cases, the Standing Start was mandatory, with Rolling start prohibited!
Best Regards,
Old Smokey
For the regulatory Authoroties that I have done Performance work for, a roll-on takeoff (with minimum 10 knots) is considered as equivalent to a standing takeoff
Beware that this might not be acceptable to all regulatory authorities (It was so in Australia for 3 types submitted to them). Douglas (in the pre-McD days allowed this for the DC9).The takeoff roll increased (60m or 200ft) for the rolling takeoff was type specific for a Bombardier product that I did work for. It may differ for other aircraft. Essentially the 60M/200 ft penalty was the delta between Standing Start and Rolling Start total distance, the actual distance to achieve Full Takeoff thrust would exceed 60M/200 ft, but at this point, some reasonable speed would already exist.
Boeing's statement that there is negligible difference (less than 50ft) regarding the takeoff roll between the standing takeoff and the rolling takeoff is rather brave. If the takeoff is NOT Field limited, the penalty would be zero. If Field limited (particularly with a Tail-wind) the penalty can be up to 5% of RTOW (That's a 15000 Kg penalty for a B777-300ER).
All AFM scheduled performance is based upon the Standing Start, and that is what I provided when producing RTOWs. As The Rolling start is operationally preferred, I added an RTOW correction at the bottom of each column on RTOWs produced. As stated before, many times it was Zero (long runways), but up to 5% of RTOW when the Takeoff was Field limited (particularly in Tail-winds). In extreme cases, the Standing Start was mandatory, with Rolling start prohibited!
Best Regards,
Old Smokey
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ICAO in their wisdom...is recommending adopting rolling starts. Their reasoning is that the engine balance can be achieved prior to entry onto the runway.
Unfortunately, this is pure bean counter mentality, as according to this scenario, the runway occupancy time is reduced, as you have technically not entered the runway space...
Less runway time equals more capacity....
it just that easy.
Unfortunately, this is pure bean counter mentality, as according to this scenario, the runway occupancy time is reduced, as you have technically not entered the runway space...
Less runway time equals more capacity....
it just that easy.
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Its in the GANIS documents
Home - Global Air Navigation Industry Symposium (GANIS)
as well as the ACE Safety case guidance....
http://www.eurocontrol.int/airports/...ase%20v1.0.pdf
Home - Global Air Navigation Industry Symposium (GANIS)
as well as the ACE Safety case guidance....
http://www.eurocontrol.int/airports/...ase%20v1.0.pdf
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stilton
"It is more advantageous, even on a short runway to do a rolling take off, the benefit of keeping your momentum going rather than having to accelerate from a dead stop is considerable in runway distance used."
What are you basing this statement on?
This is certainly not the case in any aircraft I have flown, and I can only imagine that the larger the aircraft, generally the longer the spool-up time and the higher the rotate speed thus the "benefit" of carrying some speed onto the runway is even less effective.
We were often very limited, and it is definately perferable to take a very small radius turn onto the centre line, thus giving max runway. To carry any useful speed onto the runway, the cut has to be very acute. This plus the spool-up time adds up to a lot of runway wasted.
Some of the military transport aircraft I have flown were not perf A, and I can tell you for a fact that 100% on the brakes works a lot better than rolling, leaving aside the extra benefit of getting a long hard look at the Ts and Ps at high power before committing to a take-off which was not going to end well if one donk failed after V1.
"It is more advantageous, even on a short runway to do a rolling take off, the benefit of keeping your momentum going rather than having to accelerate from a dead stop is considerable in runway distance used."
What are you basing this statement on?
This is certainly not the case in any aircraft I have flown, and I can only imagine that the larger the aircraft, generally the longer the spool-up time and the higher the rotate speed thus the "benefit" of carrying some speed onto the runway is even less effective.
We were often very limited, and it is definately perferable to take a very small radius turn onto the centre line, thus giving max runway. To carry any useful speed onto the runway, the cut has to be very acute. This plus the spool-up time adds up to a lot of runway wasted.
Some of the military transport aircraft I have flown were not perf A, and I can tell you for a fact that 100% on the brakes works a lot better than rolling, leaving aside the extra benefit of getting a long hard look at the Ts and Ps at high power before committing to a take-off which was not going to end well if one donk failed after V1.