Rotation technique

[Flight Safety]

To JT, Wino, 411A and others, this is a very interesting topic. I'm concerned as to why some want to REDUCE the rotation rate.. .. .Is it because if you somehow miscalculate MinVr to too low a value, then do the normal rotation rate of 2.5/3 degrees per second to the correct pitch attitude, you will then get a tail scrape? It seems to me that this procedure requires that your MinVr calculation be correct, otherwise a pitch attitude of 15-17 degrees WOULD result in a tail scrape if the aircraft stays on the runway.. .. .Here's an example to illustrate my question.... .. .NTSB Identification: DEN90LA046 . The docket is stored on NTSB microfiche number 40608.. .. .Scheduled 14 CFRPart 121 operation of Air Carrier UNITED AIRLINES. .Accident occurred Tuesday, January 16, 1990 at NEW YORK, NY. .Aircraft:BOEING 757-222, registration: N505UA. .Injuries: 176 Uninjured.. .. .WHILE PREPARING FOR FLT IN A BOEING 757, THE 1ST OFFICER (FO) INADVERTENTLY COMPUTED THE TAKEOFF DATA BY USING THE BOEING 767 DATA. V1, VR & V2 SPEEDS WERE CALCULATED TO BE 115, 118 & 129 KTS. THE CORRECT SPEEDS SHOULD HAVE BEEN 145, 148 & 152 KTS. THE CAPT DID NOT CONFIRM THE V-SPEED COMPUTATION; BOTH PLTS SET THEIR AIRSPEED BUGS AT THE IMPROPER SPEEDS. DURING LIFT-OFF, THE ACFT WAS OVERROTATED & THE LOWER AFT FUSELAGE CONTACTED THE RWY. THE CREW NOTED A 'JOLT,' BUT ELECTED TO CONTINUE TO THEIR DESTN AFTER DISCUSSING THE SITUATION WITH MAINTENANCE PSNL. AFTER LANDING, DAMAGE WAS NOTED TO THE LOWER AFT SKIN, AFT PRESSURE BULKHEAD & ASSOCIATED STRUCTURE. . .. .The National Transportation Safety Board determines the probable cause(s) of this accident as follows. . .. .OVERROTATION OF THE AIRCRAFT DURING TAKEOFF. FACTORS RELATED TO THE ACCIDENT WERE: THE FIRST OFFICER'S IMPROPER USE OF THE FLIGHT MANUAL, WHICH RESULTED IN HIS IMPROPER CALCULATIONS OF THE ROTATION SPEED, AND INADEQUATE SUPERVISION CONCERNING VERIFICATION OF THE TAKEOFF DATA BY THE CAPTAIN.. .. .(Edited to insert the NTSB example). . . . <small>[ 10 March 2002, 03:42: Message edited by: Flight Safety ]</small>

[Prince of Dzun]

411a:. .I flew the Lockheed 1011 for five years and I don't remember any different " feel" at heavy weights. Also the Lockheed training captains who were also Lockheed production test pilots never suggested anything about modifying the rotation rate under any conditions. Their attitude was do it the same each time and that was good enough for me. What is your reasoning for doing it differently ???. .. .Blip:. .You think too much. If you don't do it corectly all the time how in the name of heaven are you going to do it right when things are going wrong.. .Different type ratations on different days does not make sense to me. . .. .Lord Melchet:. .It's something someone else ( the expert) teaches you. First it feels right, second it looks right and third it is right. You don't need any fancy number counting. . .. .Prince of Dzun

[411A]

Prince of Dzun--. .Should an engine fail just at rotation on a max weight takeoff, the climb out at V2+10 is much easier than at V2, especially for very junior F/O's.

[Prince of Dzun]

411A:. .That's all very well but you seem to be forgetting that with a balanced field length you still must achieve the screen height. You and I know balanced field lengths are sometimes hazardous affairs and they are often followed by obsctacles which make the screen height marginal. Why not do it everytime the same way so that when the max effort day arrives it is just a little easier.. .. .Prince of Dzun. .. .P.S. I have a definite view on whether the call should be " rotate" or " vee ah" and I'd be pleased to hear your views on this prior to a discussion.

[411A]

Prince of Dzun--. .The correct terminology should be IMHO, "rotate".. .Many it would appear(especially in the UK) have a fixation about screen height. This is all well and good, however, in order to achieve controled flight, one needs to keep the blue side UP. The margin of error at V2+10 is MUCH greater than at V2.. .Reference the AA DC-10 accident at KORD a few years ago. In simulator reinactments, those pilots (very few actually) who put the nose down to achieve flying speed did not roll over on their backs. If you cannot maintain the blue side up, screen height has little significance.. .These are my views anyway, and they have served me well for over 35 years.

[Zico]

Excuse me my ignorance, but the poor fellows at KORD were (I believe) convinced that they had enough speed. Hence they saw no need to lower the nose until it was too late.

[Prince of Dzun]

411A:. .I have to concede your argument is sound, however if you pin the attitude exactly (good rotation) and hold it steady (neutral aileron and correct rudder pressure) the aircraft will climb all day with an engine out and the speed right on V2. Why should she roll over? Well, she will roll over due to fiddling around and if you want to build in some protection for that then you certainly have a point. Nevertheless, I always felt I was paid to enforce the SOPs and that's exactly what I did. I never had to do it for real and I consider I was lucky considering I spent more than two years off the surface of the earth. Regards,. .. .Prince of Dzun. .. .P.S. Pleased to see you go for " rotate" because I go for "Vee ah". I'll give you my reasons for this tomorrow.

[Wino]

411s answer is [tut tut!].. .. .The Ord DC10 crashed because all the Leading Edge devices retracted on the right side of the aircraft after the engine pylon seperated from the wing damaging the hydraulics. At the time there were no downlocks on the Slats, they were simply held down by hydraulic pressure. During the grounding of the DC10 , that was one of manythings that had to be fixed before the DC10 was allowed to fly again.. .. .Targeting v2+10 is normal procedure on rotation now. You go strait to it with now hesitation. If you get airborne and then lose an engine you hold what you got. If you chuck an engine at V1 that same rotation takes you right to v2. Its a beautiful thing. Samething everytime.... .. .Cheers. .Wino. . . . <small>[ 11 March 2002, 04:25: Message edited by: Checkboard ]</small>

[Prince of Dzun]

411A:. .When the word "rotate" is spoken or shouted it comes across the flight deck as a command to do something and do it now. This in turn tends to raise the temperature a little and the pilot flying reacts accordingly by (in extreme cases) hauling the aircraft into the air rather than flying it into the air with a smooth steady input. The "increase in temperature" can cause a tail strike especially on short runways when the shouter is sometimes phased by the end of the runway rushing towards him. On the other hand, "vee ah" tends to be spoken quietly and comes across in an advisory capacity. The pilot flying then reacts more sedately with a correspondingly smooth more controlled rotation. The company I flew for operated Convair 880, B707, L1011 and B747. Armrests and "vee ah" was what they insisted on and I did this for 20 years on the four different types. To my knowledge there was never a single tail strike over the entire period and I often thought that perhaps "vee ah" contributed much to this excellent record. Over to you.. .Regards,. .. .Prince of Dzun

[Prince of Dzun]

Wino:. .I do not agree with what you say about attitude and V2. You cannot expect to hold V2 with an engine failure at V1 if you don't reduce the normal pitch attitude by some small amount. My memory for the B747 classic puts this at 2 degrees less for 3 engines. Company procedures required the take off data card to be displayed prominently for both pilots to see and the top lines on the card (in big printed letters) said:. .. . 4 engines 15 degrees. . 3 engines 13 degrees. .. .This took care of the max take off weight engine failure at V1 as 13 degress always without fail gave exactly V2. Of course any weight less than max gave a higher speed. The point is that by holding the selected attitude steady the climb out profile was always assured. Easy: no thinking required. It was not for me to question this. My job was to do it. In conclusion, I must say I never flew a big twin so perhaps they are different. . .There is something magical about the perfect rotation. All that weight slotted just where you want it and with so little effort. Equal to a good landing because it's a small personal achievement. No one knows about it except yourself.. .. .Prince of Dzun

[411A]

Well Prince of Dzun, your point about Vee ah..is a good one and if it worked for you all those years, then who am I to critisise. I have worked for five different companies (sixth soon) operating the TriStar and they all did it differently. Strangly, none used the Lockheed recommended checklists or procedures exactly...yet Lockheed spent a LOT of money developing these procedures. In our new venture, I am in a position to insist how it will be done..and it will be Lockheed all the way. Lockheed will send us a tech rep as well who will ride around with our crews (many of which have never flown the aeroplane) to try to standardise procedures. There will NOT be any "..well we did it this way at BA.." with our guys.

[john_tullamarine]

411A,. .. .I could always be talked into coming along and helping out .......

[Mud Skipper]

Perhaps it's embarrasing to admit I think I still move my lips as I rotate. One thousand, two thousand, etc. I've found a continuous rotation works just fine, yes the aircraft may lag around 10 deg. Final pitch settling down with V2+20, we always use ICAO B for departure unless ICAO A is stipulated.

[Chesty Morgan]

Just to let you all know, I was going through the motions of a slower rate of rotation, as the aeroplane flew itself off at about 10-12 pitch we had a fairly large loss of airspeed (gust/WS) and this resulted in us being airborne for a slightly shorter time than intended!! The resultant touchdown was sufficiently hard enough to stop me doing it again.