CosmicCruiser From United States of America, joined Feb 2005, 2254 posts, RR: 16 Reply 2, posted (8 years 6 months 3 weeks 6 days ago) and read 3222 times:
The pitch attitude is high but not to the extent that you would hit the tail. I always preface my statements by saying "from the jets I know" so most jets hit the tail somewhere around 10-12 deg. nose up. Eg. The MD-11 flight manual states that in a no flaps/no slats app. do not hold the a/c off and make a normal flare. Make only a small flare to arrest the sink and fly it on. Mainly this to prevent floating down the rnwy.
2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 61 Reply 4, posted (8 years 6 months 3 weeks 5 days 21 hours ago) and read 3185 times:
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Quoting PhilSquares (Reply 3): First of all, I don't think you'll find any of the aircraft you mention doing "no flap" takeoffs. There just isn't enough runway! So, that take care of the tail strike problem.
I wasn't implying they would be performing no-flaps takeoffs. I was referring to tailstrikes during landing. American had a rash of tailstrikes during landing in the A300 several years back, mainly due to unstabilized approaches and bounce recoveries.
If a no-flap landing requires a higher deck angle during the flare, it seems the longer aircraft would be prone to tailstrikes during landing. Just trying to find out what measures are taken in these aircraft to prevent it from happening.
AJ From Australia, joined Nov 1999, 2380 posts, RR: 26 Reply 5, posted (8 years 6 months 3 weeks 5 days 8 hours ago) and read 3094 times:
Hi 2H4, the 767 I fly is geometry limited in the -300 version.
The flight crew training manual mentions the following about tailstrikes on landing:
"A tailstrike on landing tends to cause more serious damage than the same event during takeoff.....the tail can strike the runway before the landing gear, thus absorbing large amounts of energy for which it is not designed."
The following factors are considered critical:
- Unstable approach,
- Holding off in the flare,
- Trimming in the flare,
- Mishandling of crosswinds
- Over rotation during go-around.
As for flapless landings the advise is minimal flare to avoid tailstrike. The manual then advises slight forward pressure to touch down in the correct zone.
A factor that we have seen on the line that has caused tail strikes is when the speedbrake lever is raised rapidly after a failure to auto-deploy. If the pilot flying is not prepared for the pitch up it can cause tail skid contact.
Starlionblue From Greenland, joined Feb 2004, 16358 posts, RR: 66 Reply 9, posted (8 years 6 months 3 weeks 4 days 8 hours ago) and read 2907 times:
Quoting Kaddyuk (Reply 8): I belive that the A346 anti-tailskid technology works on both landing and takeoff... but when it fails, its very easy to scrape the tail...
When it fails? Well, it's probably not that common an occurence, or? And in any case, care should be taken anyway. It's worse if computer control of the elevators should fail. The 346 is so long that the elevators move to decrease stress on the fuse from bending, and to avoid resonance vibrations.
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
Jetlagged From United Kingdom, joined Jan 2005, 2508 posts, RR: 24 Reply 11, posted (8 years 6 months 3 weeks 3 days 21 hours ago) and read 2827 times:
Quoting 2H4 (Reply 4): If a no-flap landing requires a higher deck angle during the flare, it seems the longer aircraft would be prone to tailstrikes during landing. Just trying to find out what measures are taken in these aircraft to prevent it from happening.
There's no reason the deck angle will be any higher. Vref with no flaps will be much higher, but the angle of attack, and so the deck angle, will be much the same. If anything having leading edges devices deployed allows you to pull a higher angle of attack, so in theory you have more chance of a tailstrike in that configuration than with flaps and slats up.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 61 Reply 12, posted (8 years 6 months 3 weeks 3 days 12 hours ago) and read 2756 times:
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Quoting Jetlagged (Reply 11): There's no reason the deck angle will be any higher. Vref with no flaps will be much higher, but the angle of attack, and so the deck angle, will be much the same.
Ahhhh....good point. For some reason, I was assuming identical approach speeds, in which case the deck angle would be greater. I forgot to take the increased speed (and the resulting affects on AOA) into account.
When the flaps are at five or greater on the 767 the inboard aileron droops, designed to lower the nose attitude on approach. On a flapless approach this effect is gone leading to a shigher attitude than normal. I've done them in the simulator, they are very entertaining!
The final approach is flown below the normal clean speed (Vref30+50 instead of +80). From the FCTM "Final approach body attitude will be approximately four degrees higher than normal". Mr Boeing says to "fly the aeroplane onto the runway", no mixing of words!
Scarebus03 From Ireland, joined Apr 2005, 298 posts, RR: 2 Reply 14, posted (8 years 6 months 3 weeks 1 day 12 hours ago) and read 2602 times:
On the A320 series to prevent tail strikes the flight control computers are programmed. But in the early days of the 321s I believe tailstrikes were quite frequent until the computers were modified. However this is a secondary system as the pilot has overall control. Also had several strikes with the 737-400 in DUB, Which is why they have a collapsable cartridge on the belly under the tail.
SunriseValley From Canada, joined Jul 2004, 4349 posts, RR: 5 Reply 15, posted (8 years 6 months 5 days 12 hours ago) and read 2388 times:
I am not sure how widely the report on the tail strike of SQ286 at AKL was deseminated.
For those interested go to :
www2.taic.org.nz/InvDetail/03-003.aspx - 25k - 9 Jun 2005
Clearly there are software inadequacies which allowed incorrect data to be input by the pilots and not queried.
I wonder if the accident at Halifax was a result of the same set of circumstances? As I understand from the preliminary report the investigator was puzzled by the power settings used.