Juventus From United States of America, joined Dec 2004, 2835 posts, RR: 2 Posted (8 years 4 months 2 weeks 5 days 1 hour ago) and read 2798 times:
My friend is a CO mechanic, based in IAH. I asked about the 757-winglet project that CO has undertaken. He said they are having problems, ``the winglets and autoland are not getting alone``. Is this true? Is it a speed, or a flare problem? anybody...
Drerx7 From United States of America, joined Jun 2000, 4906 posts, RR: 9 Reply 4, posted (8 years 4 months 2 weeks 5 days 1 hour ago) and read 2567 times:
Not on the 753s--not yet at least. The 753s role at CO is different from the 752s.
Sinlock From United States of America, joined Dec 2000, 1532 posts, RR: 3 Reply 6, posted (8 years 4 months 2 weeks 4 days 22 hours ago) and read 2453 times:
I recall reading that in the early in the 737 (BBJ) winglet program that the center of lift on the wing moved forward a small %. Now that caused the Trim characteristics to change, in this case it made the 737 tend to over trim.
If an aircrafts center of lift moved aft then it would tend to under trim.
The 737s was having this issue at cruise and the autopilot was updated with a the changes.
A 757 in a landing configuration is very different from a 737 in cruise, but the principal of center of lift would basically be the same. A trim issue would certainly show up with the autopilot in an autoland mode, as most of the flight down the glideslope is done with trim, with the flare being done with elevator input.
AeroWeanie From United States of America, joined Dec 2004, 1601 posts, RR: 52 Reply 7, posted (8 years 4 months 2 weeks 4 days 8 hours ago) and read 2256 times:
Only the baseline (winglet off) flight tests have been completed. No flights have been made of any 757 with winglets. Hence, this report is nonsense.
Sinlock From United States of America, joined Dec 2000, 1532 posts, RR: 3 Reply 8, posted (8 years 4 months 2 weeks 3 days 21 hours ago) and read 2175 times:
My post was made with the assumption that information was based results found during simulation.
Calpilot From United States of America, joined Oct 1999, 995 posts, RR: 15 Reply 9, posted (8 years 4 months 2 weeks 3 days 17 hours ago) and read 2108 times:
Well From what I heard from a IOE Captain this is not nonsence Aero.
After the engineering came out, they discovered that the airplane would lose Cat3 because the Auto flight system softwear, did not recognize the changes during the "flare mode". They relized that the increased lift during ground effect, was going to produce a unacceptable over shoot in the touchdown zone.
I suspect the computer experts will solve this soon...?
AeroWeanie From United States of America, joined Dec 2004, 1601 posts, RR: 52 Reply 10, posted (8 years 4 months 2 weeks 3 days 11 hours ago) and read 2037 times:
Until the aircraft is flown with winglets, this is all speculation. The flare might change and it might not.
Cdfmxtech From United States of America, joined Jul 2000, 1338 posts, RR: 29 Reply 11, posted (8 years 4 months 2 weeks 1 day 12 hours ago) and read 1880 times:
The aircraft is being flown with the winglets if I am not mistaken.
AeroWeanie From United States of America, joined Dec 2004, 1601 posts, RR: 52 Reply 12, posted (8 years 4 months 1 week 6 days 16 hours ago) and read 1723 times:
Just checked - the winglets have not been installed yet, so it hasn't flown with them.
Max Q From United States of America, joined May 2001, 3289 posts, RR: 19 Reply 13, posted (8 years 4 months 1 week 6 days 12 hours ago) and read 1683 times:
Even if this was true, it's a non event, the NG 737's had the same problem, it will just require some refining and software changes, that's what a flight test program is for.
The bs that float's around airlines is endless but baffling in it's number of believers, before our 764's were delivered such priceless one's as 'there's no tail clearance so you'll have to rotate at 200kts' or 'with the new windows and the weight saved in the structure it bend's too much and will have to be redesigned' or 'it's so underpowered it will barely make NY-LA'
I wouldn't put much stock in ANYONES opinion until the flight test program is complete, as noone would know until then.
The best contribution to safety is a competent Pilot.
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