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Orlaam

Issue with Alpha after Takeoff

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I've read a couple threads here regarding the steep AOA and problems with AP on takeoff, but even after reading those threads and some manuals, I'm still lost. FYI, I've made sure the override options for flight controls and throttles are set to NEVER although I'd like to be able to use them. Actually tonight, I bunped the yoke and AP shut off, but I have this option unchecked. Why I wonder?Anyhow, most of my flights are short hauls, so my load is light and I end up climbing way past V2 +10. I tried tonight to see if I could pitch to maintain V2+10 early enough, but following the 2.5 degree or less than 3.8 degree per second pitch "rule" doesn't allow me to stay close (above) to V2+10 and I always end up going about 180 knots. In my test tonight I pitched to the max I've read of 25 degrees, but that didn't even do it, and when I engage AP, even above AH or climb thust, I still start to lose IAS and fall into Alpha. This seems to happen more lately. In the beginning I wasn't having any problems with airspeed no matter when I engaged the AP and FCP modes (pitch). I've been trying to wait until 4,000 feet, which has been well above AH and I still have issues. I'm still trying to Dx the problem, but how can I get the aircraft to maintain current climb speed and pitch when I'm way past V2+10 and below or even above AH and/or climb thrust. Pulling the IAS knob to try and force it to 250 doesn't seem to work. I'm frustrated when I can't seem to make it maintain or increase airspeed, regardless of how much higher I am than the V2+10 bug. Losing airspeed is not normal or safe IMO, so I'd think there has to be a way to do it.I'm even wondering if ASA is interfering since it was working great a couple weeks ago.If I'm home tomorrow night I'll try some more tests and even post pics if needed.

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That sounds very weird. I won't claim to be a pro, but one thing pops to my mind: flex temp?

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Yes, but mostly 30 or 40. I don't see how that could effect it??

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Chris: When you are light it helps to reduce TO thrust, which is what the flex number does for you. It is possible to take off with light fuel and one pallet of cargo and maintain V2+10, I don't recall the pitch angle but I do remember things happening pretty darn quick. I'm pretty sure that this aircraft is not flown often light... that would be poor economics... even on short hauls. Put some cargo on board and earn a profit.

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Well, I'll experiment tonight if possible. It's just odd that my flights before never dropped airspeed, but lately they have, and I haven't changed much. If anything I'm trying to learn more.

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We know there is an adjustment forthcoming with weights & balance, if that is the problem then the next update will address that. However, the problem usually asserts itself with aft-cg and my workaround was to decrease trim 0.3-0.5 from MCDU number to neutralize the nose up tendancy. I thought your problem was the opposite, you couldn't get enought nose up to control IAS. Sorry, my confusion.

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May sound obvious, but you do know that the 3 degree pitch rule only applies for the first 3 seconds or so? It is to prevent tail strike etc. Once airbourne, try to use the speed trend indicator to fly the FD bars. If your nose is below the FD but the trend indicator shows your speed increasing a lot, a generous nose up movement may be required, while if the speed trend is negative, you can push the nose down even before the FD shows it is needed. Remember that the objective is to stabilise your speed, not to fly at a specific pitch. Paul Smith.

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May sound obvious, but you do know that the 3 degree pitch rule only applies for the first 3 seconds or so? It is to prevent tail strike etc. Once airbourne, try to use the speed trend indicator to fly the FD bars. If your nose is below the FD but the trend indicator shows your speed increasing a lot, a generous nose up movement may be required, while if the speed trend is negative, you can push the nose down even before the FD shows it is needed. Remember that the objective is to stabilise your speed, not to fly at a specific pitch. Paul Smith.
Yes, thanks. I do only rotate ~3 degrees to prevent tail strike, then pitch slightly faster once clear. Last night I was able to rotate and pitch to a nice AOA whereby my speed stayed really stable, but I waited until above acceleration height to engage AP, which allowed speed to build and not drop as previous.I would just like to be able to understand engagement of AP below acceleration height or even climb thrust without losing speed, if possible. It has to be possible is V2+10 is lower than the speed captured after rotation, no?FWIW, I also used ASv6.5 instead of ASA last night, but I can't say if that really made the difference or not. I'm hoping some of the issues with ASA are worked out because overall, it's a really nice Wx engine and interface.

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