Expert: D. Norkus - 1/28/2007

Question
How did flight 232 survive a direct hit on its port wing with an anti-aircraft missile? I heard it landed without any hydraulics? How hard is that for a commercial aircraft to do?

Answer
Kevin

United 232, which crashed in Iowa on July 19th 1989, was not struck by an anti-aircraft missle. UAL 232 had a catastrophic failure of a fan disc in their #2 tail mounted engine that caused a total hydraulic failure. When the engine blew apart, pieces destroyed the an accessory drive resulting in the loss of the #2 hydraulic system. Over 70 pieces of shrapnel penetrated the horizontal stabilizer and severed the #1 and #3 hyd lines as well. This resulted in their total hyd failure.

Another issue the crew had was that their rudder was jammed over, so the plane was in a constant turn leaving them with marginal controlability. They used the thrust off the remaining wing mounted engines to help direct the planes course. Even with the total hyd failure, Captain Al Haynes managed to manever the DC-10 to Sioux City for an attempted landng.

Read a summary of the UAL 232 accident here-
http://aviation-safety.net/database/record.php?id=19890719-1&lang=en

I think you are confusing this accident with a DHL/ European Air Transport Airbus A300 that was struck by an Iraqi insurgents SA-7 'Grail' surface-to-air missile on Nov 22, 2003. As a result of this strike, the crew also experienced a loss of hydraulics.

"The aircraft had taken off from Baghdad airport. The missile struck the left wing, disabling all three hydraulic systems and setting the wing on fire. The plane began a dangerous phugoid (vertical oscillation) but the crew managed to land safely at the airport despite only being able to control the plane by adjusting the engine thrust. No other crew had ever been able to achieve a landing in this fashion, though the crew of United Airlines Flight 232 was able to also navigate their DC-10-10 after a similar triple hydraulic failure."
from - http://en.wikipedia.org/wiki/Dhl

This is a link with Power Point file (download a power point viewer at Microsoft.com if you do not have one) discussion of the accident and photo slideshow of the aircraft-
www.gosos.com/ZZZFly/imagesFly/94779_Fleet_News_12NOV04_26_Baghdad.pps

Read the award citation to the flight crew here-
http://www.flightsafety.org/citations/dhl_cit.html

Here is an article about both accidents that draws a comparision-
http://www.freerepublic.com/focus/f-news/1037084/posts

...and Capt Haynes recollection of the accident in a transcript of a lecture here-
http://www.brevardaviationassociation.org/SafetyFlight.html

How hard is it to manuever with a total hyd loss? Fairly difficult, especially if the aircraft does not have "manual reversion" or cables connected to the yoke & rudder pedals that enable the pilot to move the control surfaces by input force. (All Boeing aircraft do. The Airbus is fly-by-wire and the DC-10 has it's control cables connected to servos that use hyd pressure.) It is even more difficult to control an aircraft with a jammed rudder like UAL 232 experienced. Even though their situation was very dire and they were on fire during the entire emergency landing sequence, luckily the EAT/DHL crew still had functioning flight controls to maneveur the aircraft. A luxury Al Haynes and crew did not.

Although the Wikipedia article states, "...No other crew had ever been able to achieve a landing in this fashion" about the DHL crew, that is not really true. American Airlines 96, also DC-10 like UAL 232, experienced a hydraulic failure back in June of 1972. This was due to an incorrectly latched cargo door that blew out causing a collapse of the rear cabin floor. The floor contained the hyd lines which were then severed as the floor collapsed into the cargo bay below. Like UAL 232, AAL 96 also had a jammed rudder and controlability issues but unlike 232 the AA flight did have the use of their #2 engine to help control the pitch of the aircraft. In an amazing stroke of luck, AAL 96 was captained by Byrce McCormick, who had only a few weeks before simulated a hyd failure in the simulator during his DC-10 training. No one could have been more prepared for this to happen than Capt McCormick! He guided the DC-10 back for a successful emergency landing with minor damage and the aircraft was back in service only a few weeks later.

Visit this link to read an excellent recap of the incident and see "how difficult" you think it was for yourself-
http://www.contextmag.com/setFrameRedirect.asp?src=/archives/200202/BookExcerpt....