September 13, 200421 yr Stephan ;D.I guess this is something Finnair-specific then ? There's no doubt the procedure was/is taught all the time.Tero PPL(A)
September 13, 200421 yr Tero,I should have known better, Finns are no fools!Continued my research and what did I find?Mike Ray says: "As airspeed approaches V1, move the yoke aft from a position slightly forward of neutral to allow smooth rotation to BEGIN at VR".I stand correctedKind regards,Stephan Haaswww.lemont.nl/b767flightdeckhttp://www.pic767flyingclub.com/images/sas544.jpg
September 14, 200421 yr Interesting Tero.BA definitely don't do it this way. 757/767 it's LNAV armed (obv provided the dep is to be flown using LNAV), VNAV at Aa (FL CH in QFE ops) and override the VNAV speed to about 280 kts, provided no SID turn will be significantly exceeded.I wonder why Boeing don't recommend LNAV to be armed at the gate?It even says in the BA FM that you should arm LNAV (if appropriate) as part of the AFDS cockpit setup. It's very interesting to see how different airlines have different operating philosophies. I see it from my garden sometimes (believe it or not), all-be-it on a rather superficial scale. I live near about 3 miles west of Heathrow and so get a good view of a lot of N.America traffic - maybe it's my imagination but the UAL, ACA & AAL Boeings all seem to pass over pretty high (on a very regular basis, so weight of aircraft can't really be the answer) and seem to be travelling a lot slower. BA and Virgin a/c seem to want to gain speed instead of altitude and are often seen much lower and much faster. Am I chatting crap here - anyone else?
September 14, 200421 yr The instructor told me that with the SW version they're using on the 757s it's forbidden to ARM either LNAV or VNAV on the ground (they have Pegasus equipped FMCs on every 757). I remember some talk about messing up the logic or something. Now that we got into the topic, I'll find out what is the exact reason. Strange too, that he told me that it's Boeing's recommendation (ie, not something that you will find from the base manual package, because I haven't found one either) that those modes never be armed on the ground, regardless of the SW the aircraft is using. What is your source on BA arming LNAV on the ground ?You're probably very right in your observations about the aircraft flying departures a bit differently. Some airlines have Vref+80 until 3000ft modified VNAV climb (some fly the first part with FL CH of course), some start accelerating to 250 or above (if allowed) right after passing the std Boeing recommened accel ht 1000ft. Obviously these aircraft will be passing your house at a much lower altitude than the ones taking ref+80 up to 3000ft.Tero PPL(A)
September 14, 200421 yr Well Tero,Regarding the pulling back on the yoke before Vr, in the quote mentioned above, it is indeed done, but not the way you (seem to) say it. One procedure is to push the yoke forward during the initial part of the takeoff roll, to increase forces on the nosewheel and increase lateral controllability. Since this also increases wheel friction drag, you should definitely ease back on the yoke when approaching V1/Vr. By that time the rudder should be plenty effective anyway.As mentioned in the quote, the yoke can be eased back to slightly FORWARD of neutral. This is still not pulling back on the yoke. You're still pushing.If you would pull on the yoke before Vr, you really do risk a tailstrike, especially if your takeoff trim is not 100% correct (which can happen if for example the bag loaders don't exactly load the way it's on put on paper). Very risky, a big no-no. Iz
September 14, 200421 yr Iz,I'm aware of the pushing during takeoff roll to make the steering more effective. However, this is just what I was told, I'm not making it up :).Tero PPL(A)
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