Letters to the Editor

SUBJECT: MD 10 Model
FROM:  
Thom DiGiacomo  <PDGTDG@aol.com>

I am very disturbed about the FAA’s certification of the Boeing MD10.

Boeing offers a retrofit package to all those flying the DC10.  That package converts the 3-pilot, standard avionics cockpit of the DC-10, to a 2-pilot "glass cockpit".  The reworked DC10s will carry the new designation of MD 10. 

That Boeing conversion saves the operator the cost of the third crewmember plus future training costs, because MD-10 pilots will be able to transition to the MD11's without recertification. 

What disturbs me is that the landing characteristics of the MD 11 are very different from the DC 10  The MD 11 has a much shorter horizontal stabilizer, making landing more difficult than in a DC10.  MD 11 landings require excessive pilot input due to its inherent instability, which is most apparent when it is slowed to landing speed.

Boeing and the FAA seem to be ignoring that critical difference.  I am concerned that FAA certification might convey a false sense of security to pilots that transition from MD10s to MD11s.  

I think this decision is misguided and should be reconsidered.  My suggestion would be to correct the horizontal stabilizer on the MD11's along with this retrofit to bring the flying characteristics of the two planes more closely together.

I would greatly appreciate your comments on this issue.

 

EDITOR’S REPLY:

I agree: the MD-10 and the MD-11 should require separate pilot type-ratings; or failing that, any airline that operates both models, should not require pilots to be dual-qualified on both.

However, I doubt that redesign of the horizontal stabilizer, on the MD-11, is economically feasible.  I suspect that would be so costly it would be better to junk the MD-11s and buy new planes

The Fed Ex MD-11 crash at Newark, in July, 1997, was found to be a combination of bad pilot judgment and over controlling the airplane at touchdown.  The lack of pitch stability on that plane probably made the difference, as it apparently did in other landing accidents, such as the one at Hong Kong, and the two at Anchorage, Alaska.  I have yet to hear the cause of the loss of the Fed Ex MD-11 at Subic Bay, Manila.  That one should be interesting, since they had a very long landing runway (12,000 ft.).  There was another hard landing, by a Fed Ex MD-11 at Newark (same runway as the July, ’97 crash) in Oct. 1999, that did substantial damage to the center landing gear.

I think your concerns are justified, not only as to the greater difficulty of landing the MD-11 safely, but also as to its hypersensitivity in the pitch mode, when flown manually, at cruise altitude.  That defect in design, on the other end of the flight speed envelope, has already killed and caused substantial damage.  For more, see the FAQ on the MD-11.

March, 2001

Robert J. Boser    
Editor-in-Chief 
AirlineSafety.Com

Return to the Letters to the Editor page.


HOME | UNIONS | FREQUENTLY ASKED QUESTIONS | WHAT'S NEW? | EDITORIALS | LETTERS TO THE EDITOR 

QUOTATIONS | AVIATION NEWS  | BOOK REVIEWS | SAFETY ARTICLES | LINKS | CONTACT US

All Material © 1997-2014  All rights are reserved. No part of this web site may be reproduced in any way without expressed written consent