FAO: Gabe. Relentless Takeoff Pull Up. FOFFIEness.

[ATLcrew]

Is there upwards of 50 kts of variability in your climb out speeds below 10,000 feet that are somewhat associated with the level of traffic?

Huhwha?

[Evan]

What you say is geometrically correct but it is not how airplanes are flown.
If the pilot wants to hold 180kts (and in climb pilots almost ALWAYS want to hold a given speed, not a given attitude or a given vertical speed), instead of doing what you say after retracting the gear he pitches up from a climb angle of 10 to a climb angle of 12 degrees, the speed remains at 180, and the vertical speed increases even more than in your scenario.

3WE, Evan,
Gear retraction almost ALWAYS happens very early during the climb, just after lift off, well below, when neither the speed, not the attitude, nor the vertical speed have stabilized yet. The plane is still pitching up, accelerating and increasing the climb speed, so the effect of the gear retraction is "masked" by all that variation. The only difference (if the gear is retracted vs if it is not) is if the plane will finally stabilize at 180kts, 15deg and 3000fpm or 180kts, 17 deg and 3500 fpm (invented numbers, just to forward the idea). Engaging the AP will come afterwards, when the plane is stabilized in the climb.

I don't recall saying anything about gear retraction. What I'm pointing out is that once you've reached acceleration height, retracted flaps and done the checklist, the climb is going to almost always be done on autopilot and many pilots are probably on VNAV after 1000' AFE. If the profile is in the FMS and there are no issues restricting that, there is good reason for this to be done in VNAV, which will fly the profile better than any pilot could. 3WE mentioned FLCH, which is often used when an unrestricted climb is desired at a constant thrust and a lot of pilots use V/S later on, near cruise level to give a smoother ride (although V/S in climb is potentially dangerous and some operators forbid it in climb). In terms of autothrottle, FLCH will give you the max rated thrust in CLB (assuming you are making a large change in flight level), maintain the current or selected speed (or FMS target speed if it is valid) and fly that with pitch. Another alternative is to use FPA and these modes have different names and behaviors in different aircraft so you might use IAS HOLD or VNAV CLB, etc, etc. I see a range of personal preference amongst pilots on forums for climb modes. Some want a smooth rise. Some want economy. Some want an expedited climb. Some use more of a cocktail approach. Some use more of a cowboy approach...

What I don't see is a lot of manual climb going on above the acceleration height.

Also, while these modes are either going to result in pitch or power occillations, I wouldn't expect to see speed variations like he is claiming. Perhaps 3WE is experiencing the limitations of smartphone GPS. I don't think it's using doplar and the sample rate might be smaller that GPS avionics. I also wonder how the vertical motion might affect simple GPS units.

[3WE]

...Gear retraction almost ALWAYS happens very early during the climb, just after lift off, well below, when neither the speed, not the attitude, nor the vertical speed have stabilized yet...

Ok, no argument with that and MAYBE point taken.

Still...Atlanta 26L (which "never" has traffic crossing down field due to the end-around taxiway), is launching planes "as fast as they can pull on the runway" on a sunny day....I can imagine* a somewhat slower climb out there versus a po-dunk airport with a departure every five minutes.

*Correction, I'm not "imagining it"- I HAVE IN FACT OBSERVED IT FROM THE VERY RUNWAY/AIRPORT I MENTION versus the low-traffic outlying airport where I left before arriving at Atlanta.

And to restate- a plane might easily be at 1,500 ft AGL within a minute of lift off and needing to adjust it's climb for a preliminary level off at that point too.

The "period of strict, high performance speed control" could easily be a short one!

[UncleFire]

Try flying out of John Wayne Airport sometime - the aircraft blasts off and then cut power - one gets that roller coaster feeling.
http://www.ocregister.com/articles/j...e-airport.html

I've flown out of SNA a bunch of times. While it is a bat out of hell take off, for some odd reason I like that better. Tons of power, get to altitude, then climb more normally.

I think Long Beach is similar.

[brianw999]

One of the most disconcerting airports to depart from is the Greek island of Corfu. When they are taking off over the land they go right into the end of runway turning circle, apply the brakes, run up to full power, let the brakes off and go for it. But, that's not the end of it. The ground at the end of the runway is a hill and it's a tad bowel loosening to be in a balls out climb with the ground coming up to meet you !

[3WE]

One of the most disconcerting airports to depart from is the Greek island of Corfu. When they are taking off over the land they go right into the end of runway turning circle, apply the brakes, run up to full power, let the brakes off and go for it. But, that's not the end of it. The ground at the end of the runway is a hill and it's a tad bowel loosening to be in a balls out climb with the ground coming up to meet you !

...all carefully calculated to work with a healthy safety buffer (hopefully without any errors. )