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Jet Climbs

DIAMONDDD

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I thought that I had read in the AIM some time ago the proper procedure for jet take offs. Something like "V2 plus 10 to a certain height and then pull power back and clean up". I tried to find it again and am having no luck. Can anyone tell me where I might have read this in an "official" sort of document? (Not Policies and Procedures and not "This is what we do".) I am looking for hard copy evidence of this and I can't find it. Did I fall off my rocker at some point? Any help would be appreciated.
DD
 

enigma

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Try looking in part 25. I'll bet that is where you saw it.

regards
 

avbug

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Takeoff performance is based on climbout at V2. This assures second segment climb performance, at must be maintained for certification purposes (and performance chart figures) to 400' minimum, up to 1,500'. This will yield at a minimum a climb gradient of 1.2 percent for two engine airplanes; 1.5 percent for three engine airplanes; and 1.7 percent for four engine airplanes.

This changes for engine-out situations, and various climb gradients are mandated for certain configurations (clean, landing configuration, etc), as well as various phases of the takeoff/go-around. For a landing configured climb, a speed of Vref is provided as the minimum speed per certification, though a manufacturer may mandate that, or a different, higher speed.

Typically departures are made at the best forward speed, rather than climbing at V2, however. 200 KIAS in the airport traffic area, 250 below 10,000, and then a given climb profile which generically is about 260 KIAS to FL 290, then .69 to .74 from there up until reaching the desired cruising altitude. The specifics vary with each individual model aircraft.
 

DC9stick

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Avbug, The climb gradients you listed are for OEI operation , there are no all engine operative climb gradients that I'm aware of because with all engines operating performance will always be better than the OEI gradients.

The climb profile we use in the DC-9 is rotate to approximately 15 degrees of pitch, climb to 1000 AGL, this will result in a speed above V2 and is acceptable, then retract flaps set climb power accelerate to 200 or 250 depending on type of airspace, at 10,000 accelerate to 320 to mach crossover then climb at mach .74 to cruise altitude, cruise .76 to .78
 
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banned username 2

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avbug said:
Takeoff performance is based on climbout at V2. This assures second segment climb performance, at must be maintained for certification purposes (and performance chart figures) to 400' minimum, up to 1,500'. This will yield at a minimum a climb gradient of 1.2 percent for two engine airplanes; 1.5 percent for three engine airplanes; and 1.7 percent for four engine airplanes.

AvBug,

The gradients you quoted are for the enroute segment climb, Second Segment Climb is as follows:

Takeoff: landing gear retracted. In the takeoff configuration existing at the point of the flight path at which the landing gear is fully retracted, and in the configuration used in Sec. 25.111 but without ground effect, the steady gradient of climb may not be less than 2.4 percent for two-engine airplanes, 2.7 percent for three-engine airplanes, and 3.0 percent for four-engine airplanes.

Final takeoff: In the en route configuration at the end of the takeoff path determined in accordance with Sec. 25.111, the steady gradient of climb may not be less than 1.2 percent for two-engine airplanes, 1.5 percent for three-engine airplanes, and 1.7 percent for four-engine airplanes, at not less than 1.25 VS
 

TurboS7

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If you are looking for NA profiles you will find these as ICAO A and B in any international Jepp manual.
 

enigma

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DIAMONDDD said:
I thought that I had read in the AIM some time ago the proper procedure for jet take offs. Something like "V2 plus 10 to a certain height and then pull power back and clean up". I tried to find it again and am having no luck. Can anyone tell me where I might have read this in an "official" sort of document? (Not Policies and Procedures and not "This is what we do".) I am looking for hard copy evidence of this and I can't find it. Did I fall off my rocker at some point? Any help would be appreciated.
DD

Let me see if I can make some sense of all of this. First, I assume that you are really looking for is an exact procedure for making a "normal" proper take off and climb out. As others have noted, each aircraft uses a differing set of rotation rates, initial pitch angles, speeds, configurations, etcetra. So I can't give you an exact procedure for a "jet".

What I can do is to tell you that all part25 jets are certified to meet certain performance criteria. These criteria are mostly related to engine out performance, and in order to achieve that performance the aircraft must be flown on an exact profile. It is that profile that you seem to refer to, and I'll try and give you a generic aircraft profile.

Here goes. Assume that you lose an engine between decision speed (V1) and safety speed (V2) on takeoff. The procedure is fairly well defined; you rotate at some specified rate of rotation to a pitch attitude that results in a specific airspeed (V2). Raise the gear when a positive rate is achieved and maintain V2 up to a predetermined "level off, or acceleration" altitude. When reaching acceleration altitude ( usually 800 to 1000ft agl) you level off and accelerate. When the a/s increases to flap retract speed, you retract the flaps and then continue to accelerate to a slightly faster climb speed. When climb speed is achieved you hold that speed and climb until obstacles are clear, or until a minimum safe altitude is reached. The speeds, and altitudes are dictated by the performance requirements of part25.

Bottom line, I don't know of an AIM ref for the procedure, but part 25 gives exact criteria and the procedures are derived from that criteria.

regards
 
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