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tarzanboy
Topic Author
Posts: 124
Joined: Fri Sep 12, 2003 8:18 am

Avoiding Accidents Or Incidents On Rotation

Tue Jul 20, 2010 10:40 pm

Have a quick glance at the below quoted article. Now the B747-400 will whack its tail on the ground at 12.5 degrees with the wheels extended [I am not sure what is the figure with the oleos compressed]. Now I admit the weight calculation should not have been overlooked but my point is this. Looking at the 744, in this day and modern aviation age, why can't the below rotation procedure be adopted:

I refer to the 747-400 in this case and I assume it strikes its tail with the GEAR COMPRESSED at a pitch over 10.5 degrees and under 12.5 degrees. Okay, let's just assume this.

At VR rotate the normal 2.5 to 3 degrees per second monitoring your PFD closely and briefly stop at 10 degrees pitch and stay there until you are about 36-50 feet above the ground and then continue rotation to your desired climbout angle. That's all to it! 10 degrees is a lot and if the calculations are right, liftoff should definitely have taken place by then. This pattern and rotation 'pitch stop' could be applied to many other airplanes. Straying from the topic here, I was once told that in the DC8 manual the rotation technique is to stop at 8 degrees until airbourne and then contonue rotation further.

Coming back to the topic, in terms of 747-400s [and the previous geometrically similar variants of the 'yesteryears'] tail strikes on takeoff could be avoided with this technique stated above.

I must note however, that in the particular 747 tail scrape incident as you will read in the below article, I think the technique that should have been used in that case was stop the rotation and hold it at 10 degrees and apply TOGA thrust.

I welcome your comments. I am seasoned in this thing now.

THE ARTICLE

"Boeing 747-412 9V-SMT, flight SQ286, tail strike during take-off,
Auckland International Airport, 12 March 2003
On Wednesday 12 March 2003, at 1547, flight SQ286, a Boeing 747-412
registered 9V-SMT, started its take-off at Auckland International
Airport for a direct 9-hour flight to Singapore. On board were 369
passengers, 17 cabin crew and 3 pilots.

When the captain rotated the aeroplane for lift-off the tail struck
the runway and scraped for some 490 metres until the aeroplane became
airborne


http://www.aviationkb.com/Uwe/Forum....-strike-AKL-March-2003-TAIC-Report
 
Fly2HMO
Posts: 7184
Joined: Sat Jan 24, 2004 12:14 pm

RE: Avoiding Accidents Or Incidents On Rotation

Tue Jul 20, 2010 11:10 pm

You're only making a simple procedure more complicated and the only thing you could accomplish for sure with your procedure is increased take-off rolls, which is the last thing you want in a fully laden 747 on a high altitude airport.

A couple of whoopsie incidents won't justify switching every airline SOP out there. Sounds like a solution looking for a problem.
 
tarzanboy
Topic Author
Posts: 124
Joined: Fri Sep 12, 2003 8:18 am

RE: Avoiding Accidents Or Incidents On Rotation

Tue Jul 20, 2010 11:51 pm

Fly2HMO said:

You're only making a simple procedure more complicated and the only thing you could accomplish for sure with your procedure is increased take-off rolls, which is the last thing you want in a fully laden 747 on a high altitude airport.


.................................

10 degrees for the 744 on takeoff and adequate flaps is a lot with TOGA as a last resort is great I think.

But you've got our own opinion................................anyway...................................... don't say I did not warn you.
 
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Starlionblue
Posts: 20482
Joined: Fri Feb 27, 2004 9:54 pm

RE: Avoiding Accidents Or Incidents On Rotation

Wed Jul 21, 2010 12:46 am

Thousands of 747 flights every day and rotation incidents are VERY rare. Why change a procedure that works? The KISS principle needs to be applied.



On a side note, I wonder what a tail strike sounds like to the people in the rear of the cabin.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Avoiding Accidents Or Incidents On Rotation

Wed Jul 21, 2010 1:27 am

Boeing already recommends halting the rotation at 10 degrees if you haven't broken ground yet. If you follow the recommended 2.5 to 3 degrees per second, and your weights and speeds are correctly calculated, you should be breaking ground by the time you reach 10 degrees. Your 2 step solution is overkill. Its not like there is a strong trend of tail strikes in the 744.

Further, your recommending technique will result in consistently overshooting V2, and distort the climb profile. This can be critical if you lose in engine in a balanced field scenerio.
Proud OOTSK member
 
tarzanboy
Topic Author
Posts: 124
Joined: Fri Sep 12, 2003 8:18 am

RE: Avoiding Accidents Or Incidents On Rotation

Wed Jul 21, 2010 3:15 am

lowrider....point taken. I did not mean to say amend the technique in general - no way! But by the way, did Boeing really say halt at 10 if you haven't broken ground? Where did you hear/see this? Great!
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Avoiding Accidents Or Incidents On Rotation

Wed Jul 21, 2010 3:31 am

Quoting tarzanboy (Reply 5):
But by the way, did Boeing really say halt at 10 if you haven't broken ground? Where did you hear/see this?

I just looked give a page reference and I had my types crossed That was not from the 747-400 AOM, but rather from the 747 classic AOM.
Proud OOTSK member
 
tdscanuck
Posts: 8573
Joined: Wed Jan 11, 2006 7:25 am

RE: Avoiding Accidents Or Incidents On Rotation

Thu Jul 22, 2010 1:33 am

Quoting Starlionblue (Reply 3):
On a side note, I wonder what a tail strike sounds like to the people in the rear of the cabin.

Like a really out-of-balance wheel...strong low vibration.

Tom.

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