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Reading about 737-900ER take off roll (3000 meters) from another question, I would like to know what this means.

Is it intended that the aircraft needs 3000 meters before it can pitch up to take off or at 3000 meters is has acquired sufficient height and should be airborne?

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    $\begingroup$ I think part of the confusion about this term arises because, in aviation, the word roll is used for two rather different things. $\endgroup$
    – Oscar Bravo
    Commented Sep 22, 2015 at 14:51
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    $\begingroup$ @OwenBoyle Saw this question on the hot network list and came here to see if an aircraft could really take off and immediately do a roll... $\endgroup$
    – Michael
    Commented Sep 22, 2015 at 15:59
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    $\begingroup$ @Michael: some aircraft actually do it. $\endgroup$
    – user23573
    Commented Sep 22, 2015 at 19:10
  • $\begingroup$ @BogdanWilli Not sure if serious... That's a great video, but was taken from a game. Not real. $\endgroup$
    – JPhi1618
    Commented Sep 22, 2015 at 19:42
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    $\begingroup$ @JPhi1618: You got me! But this one is not from a game. $\endgroup$
    – user23573
    Commented Sep 22, 2015 at 19:52

3 Answers 3

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The take-off roll, also called ground roll, is the roll distance before the aircraft becomes airborne.

In case of the 737-900ER, it will be in the order of 2000 meter.

The quoted 3000 meter is probably the take-off distance required (TODR) or take-off run required (TORR) at maximum take off weight. That assumes a full throttle acceleration to about half of the runway (1500 m), then an engine failure, continued acceleration on a single engine, rotation and take-off at 3000m. In case of TODR, the climb to a height of 35 ft is included as well (for FAR Part 23 aircraft it is 50 ft).

This means the 737-900ER requires a runway of 3000 meter length to take-off with an engine failure or to stop when the failure happens before the decision speed (V1). Since engine failures are unpredictable this is the minimum runway length required for take-off planning.

This all assumes ICAO standard atmosphere conditions. For runways at higher altitude ( > MSL) / higher temperature (> 15 deg C) the TORR will be even higher.

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  • $\begingroup$ As far as I can remember take off distance includes a height of 50ft, can you cite the 35ft? $\endgroup$
    – falstro
    Commented Sep 22, 2015 at 9:49
  • $\begingroup$ @falstro Originally I typed 50ft, then changed it to 35ft, because I thought the 50ft was for props, 35 for jets. I will verify the numbers $\endgroup$
    – DeltaLima ♦
    Commented Sep 22, 2015 at 11:31
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    $\begingroup$ @falstro 50 feet is indeed for piston transport, 35ft for jets (the 707 & dc-8 could not make 50ft at some of the available runways at the time). It is 15 feet on a contaminated (wet) runway. $\endgroup$
    – DeltaLima ♦
    Commented Sep 22, 2015 at 11:36
  • $\begingroup$ interesting, thanks! $\endgroup$
    – falstro
    Commented Sep 22, 2015 at 11:49
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    $\begingroup$ @DeltaLima: 50ft is FAR/JAR part 23, 35ft is part 25 (25.113(a) to be precise). An ATR-72's takeoff ends also at 35 ft. $\endgroup$
    – Peter Kämpf
    Commented Sep 22, 2015 at 13:03
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Take Off Roll is defined as:

The process whereby an aircraft is aligned with the runway centerline and the aircraft is moving forward with the intent to take off. For helicopters, this pertains to the act of becoming airborne after departing a takeoff area.

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  • $\begingroup$ H/T @mins for the link. $\endgroup$
    – Jamiec ♦
    Commented Sep 22, 2015 at 8:45
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737's typically take off in 3000 to 4000 feet depending on cargo and configuration.

The TORR and other statistics are runway length guidance figures that are much longer than the actual distance the aircraft rolls before it leaves the ground.

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  • $\begingroup$ The question arose due to another question regarding the 737-900ER, which requires a lot more runway than most 737s for takeoff (2,000 ft. more than a -800 and 4,600 ft. more than a -700, according to the 737 NG Wiki.) That's assuming MTOW/standard atmosphere for each of the above. $\endgroup$
    – reirab
    Commented Sep 22, 2015 at 18:48

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