I was reading an article on this crash (the one that happened right after 9/11) and something just doesnt sit well with me about it. Not trying to be a conspiracy theorist on this one, but if that really went down to wake turbulence, why has it never happened again, especially with all the A300s FEDEX flies.

Discuss........................

Variables my friend, way too much to consider. I was actually discussing that accident with a buddies dad of mine who is an FAA safety inspector. What he thought was interesting was that the vertical fin was composite material. And the 787 is pretty much a huge chunk of carbon fiber, hopefully the boeing engineers have taken that all into account. Either way, it seems a lot of people changed the way they handle turbulence after that accident.

From what I gather, training procedures have been modified at most airlines now to not use extremely aggressive rudder inputs to combat wake turbulence (full scale deflection one way to immediate full scale deflection the other). I also think that even without modified training procedures that the likelihood of doing something like this is also very rare. In 2 years in the CRJ and LOTS of wake encounters, I have never come close to a maneuver such as this (I have done a near full-scale in ONE direction before, but not even close to bringing it the other way). I just think that a very rare circumstance presented itself to this flight crew, who were also unaware that they could in fact break the tail off with extreme rudder inputs. In the investigation it was demonstrated by Airbus that the load limits had been exceeded, so they blamed American. American of course blamed Airbus for not informing them that a maneuver like this could cause a catastrophic structural failure. No conspiracy here, just an un-trained for circumstance for an unfortunate flight crew.

According to the FDR, the rudder pedals moved from 1.7 inches right to 1.7 inches left, 1.7 inches right, 2.0 inches right, 2.4 inches left, and 1.3 inches right between 0915:52 and 0915:58.5. Also, the FDR showed that the control wheel moved 64º to the right at 0915:51.5, 78º (full) to the left at 0915:53.5, 64º to the right at 0915:55.5, and 78º to the left at 0915:56.5.

The airplane performance study estimated that, at 0915:53.2, the rudder was deflected 11º to the left, and the sideslip angle at the airplane's center of gravity (cg) was about 4º to the left (after peaking temporarily at 5º to the left).21 At 0915:56.8, the rudder was deflected 10.2º to the left, and the sideslip angle was about 7º to the left. At 0915:58.4 (the time that the right rear main attachment fitting fractured), the rudder was deflected between 10º and 11º to the right, the sideslip angle was between 11º and 12º to the right, and the airplane experienced a 0.2 G shift to the right in lateral load factor.


This is not new stuff..... many years ago a B-52 lost its vertical stab on a low level in turbulence (they landed the acft with no fin). They shortened the hight of the stab which reduced the bending moment at the attach point. In spite of the mod my B-52 instructor pounded into me how not to handle the controls in turb, MITO, wakes, stalls, lazy 8s, etc. We did this training in the jet not in the sim. I have not received this type of training while at the airlines "in the jet". The closest thing we do is "upset training" "in the sim". Just isn't the same.

Training film: ( note the date )

"Flight Without A Fin"
(1964, Color, 9:56)
This film includes some absolutely amazing footage of an actual B-52 which has lost its vertical stabilizer! The film serves as a briefing on what to do in this unusual situation. This a really interesting short film!

Now in the latest HI6, our venerable "Nordstrom" Aviators are high altitude stalling their Sooper 80's at an alarming rate due to "shear" ignorance of the dead man's zone. (If we didn't "invent" it, it doesn't exist).

But being as smart (and as smarmy) as they are, I am sure they will re-invent aviation dynamics all over again and the problem will be solved.

Composite or no composite, the answer is simple. Rolling caused by vortices is controlled with aileron, not rudder. If the flight recorder data is to be believed, and I don't know why it shouldn't be, then the recovery was badly and wrongly flown.

According to 'Seconds from Disaster' the co-pilot was the pilot flying through the whole incident. He was also unaware that on the Bus, while in flight, the rudder becomes very sensitive to pedal movement. In fact, only a couple of inches of pedal movement put the rudder at the full stop. Being unaware of this he used a technique to recover from wake turbulence that he was taught by American Airlines which uses the rudder. However, by unknowingly moving the rudder too far, back and forth, he made the wake turbulence oscillations worse.

Eventually, to my understanding, all of the unusual aircraft movement was being caused by the pilot and his excessive rudder movements. As the aircraft yawed more and more the pilot's thought that they were still stuck in the wake and continued increasing control movement to try and correct. This eventually led to alternating full-stop deflections which caused a massive structural failure in the vertical stabilizer.

Hit up YouTube and search for the flight number, it's a very interesting video.

That's not correct.

At that time, the use of rudder in unusual attitude recoveries was getting considerable emphasis. The annual recurrent training on the subject included a presentation by an AA Captain ( a former military pilot) where he included control techniques that were more appropriate to high performance fighter type aircraft.

He was not, if I remember correctly, recommending or teaching rudder as the primary flight control in unusual attitude recoveries...but he was placing a lot of emphasis on rudder use.

At the time, I was surprised at the emphasis he put on these techniques...having flown fighters myself, I understood his points but thought his emphasis might be misunderstood by other pilots who might take his words out of context.

Sadly enough, that may have been the case. Thankfully, that presentation is no longer used.

That is a true statement, when flying jets the only time you use rudder is for V1 cuts, takeoff, and landing(s).

Spartan07, not just the Bus but all big jets that I have flown. They are called "feel units". Basically they are computers that correct for speed giving the pilot normal rudder/elevator/aileron inputs but limiting the actual deflection. They should have know this I would think. But when the company writing you the check every month tells you do it this way sometimes you do not have a choice.....at least in training.

That presentation is STILL being used!!! The last training event I attended showed the video. But then again the training center is being run by X-fighter pilots.

Food for thought-
Boeing also came out with the warning that their airplanes weren't built to take the rapid alternating full scale deflection of the rudder either.
A fact that was a big surprise to pretty much everybody I know since after all, if you are below the limiting speed----most of us thought stop to stop to stop wasn't even a factor---just as it is in small planes.

Another issue- AA was pretty upset with AB because there was a prior incident (over the Carib an AB went out of control and severely overstressed the rudder--stress level went well beyond the load limit {for you composite haters, had that rudder been metal it would have failed----design load limit for composite components is higher than that required for metal}) The data was sent to AB who never informed AA how close they came to losing a jet...info that might have prevented the subsequent mishap over NY.

The rudder displacement, a couple of inches left and right doesn't [I]seem[I] like it should be displacing the rudder that much, but in this case it was pretty much all the rudder the plane was going to give him. I will admit that i have no idea how much distance it takes to put the pedal to the stop, but it seems to be in the neighborhood of about 6 inches....but, seems to me like the FO was trying to lead his aileron input with a little bit of rudder. Maybe mis-applying the high AOA training AA had put him through, or a habit pattern transferred over from small airplanes vs. just riding the wave out just using airlerons.

Doesn't really matter why the FO did what he did. Question is have we all internalized the lessons from this mishap to keep it from occurring again?