Talk:Northwest Airlines Flight 85

Court testimony

This source:

• "How I Saved A 747 From Crashing." Jalopnik.

Says there was court testimony in 2006 about this. Where can I find it? WhisperToMe (talk) 17:09, 25 December 2012 (UTC)

Additional source

Apparently an ALPA article was posted at http://findarticles.com/p/articles/mi_m0UBT/is_33_17/ai_106872569 but the link breaks and robots.txt prevents the relevant text from being visible on web.archive.org WhisperToMe (talk) 17:09, 25 December 2012 (UTC)

Names of crew/interviewees in Mayday, and statements

The Mayday program says the crew were:

• Captain John Hanson (he is interviewed on the program)
• First Officer David "Dave" Smith
• Captain Frank Give(?) - The relief crew member
• First Officer Mike Fagan (he is interviewed on the program) - The relief crew member

Also interviewed on the program:

• Flight attendant Kathy Brecklin
• John Doherty (Northwest fleet training captain)
• Carolyn Deforge - NTSB investigator who oversaw the event
• Sylvie Dionne - Metallurgist specializing in aircraft components

WhisperToMe (talk) 17:14, 25 December 2012 (UTC)

More Deforge statements:

• 31:17-31:25/44:59 "It was very surprising to us when we found out what type of failure had occurred and that the effects it had had on the aircraft's uh, controllability"
• 31:42-32:02/44:59 "They opened up the access panels in the tail, and they noticed that the end cap on the control module had separated. The end cap is uh, circular piece about two and a half inches in diameter. It had had [sic] completely fractured all of the way around its diameter and had then fallen off."
• 32:30-32:41/44:59 "When the end cap came off, it allowed a piston inside the module to move further than its design limit was intended, and that is what resulted in the rudder hardover."
• 32:50-33:13 "It was certainly something that was not anticipated by the designers and, when we examined the hardware, uh, it was definitely beyond the scope of what you normally encounter as an engineer when you're doing a failure investigation. Normally you see something that's an internal failure, not an actual mechanical failure of the housing itself."
• 34:54-35:07 "The fact that this had a purely fatigue failure with no apparent origin to it, such as a deficiency or a defect made us question the, uh material properties of the housing itself"
• 35:46-35:57 (after it was revealed the material was not the cause) "It was driving all of (us/we?) crazy. We were very frustrated when we realized it. All of the paths we chased down didn't give you that aha, eureka moment."

Mayday says: Hanson said it was the first B747 in the line, and the first Northwest flew. It was the oldest B747 produced in the world. The records stated that it was a test plane before being sold to Northwest. It flew for 55,000 hours and taken off over 7,000 times, more takeoffs and landings than most 747s with that number of hours in the air.

Deforge said:

• 37:02-37:12 "We were concerned that it had been exposed to more stress than we had expected and it [sic] that may have caused it to fail"
• 37:21-37:29 "We were very concerned about those operators in Asia that used the 747-400 on short haul flights."

(but the module is broken and could not be tested - Mayday said that testing the rest of them would not be practical)

• 37:37-37:42: "You would have essentially had to have grounded the fleet to remove all of the units."

Mayday said that NTSB recommends that airlines test the power control module more vigorously and more regularly (this seems to be the airworthiness directive talked about in the article right now) as a way of pre-emptively preventing future failures

• 37:54-38:00 "We instituted a repetitive inspection cycle requirement"

Mayday said that the root cause of failure is never found. Four years later, an Air France Cargo plane had to make an emergency landing (program doesn't say where, couldn't find BEA report so it may have taken place outside of France), lower rudder failed on 747-400, circumstances are similar to NW85.

• 38:25-38:39 "The unit was sent to Parker Hannifin in California for repair, and when they opened the box and looked at it, their eyes got really big, they immediately quarantined it, and called everyone, and said 'Oh my gosh, you're not gonna believe what just showed up on our doorstep!'"

Mayday says there is possibility that investigators can explain mysterious failures if AF module shows signs of fatigue.

• Deforge: 38:50-38:59 "We immediately focused in on the fracture surface again, in the same area, and did many of the checks that we had done the first time around."

Mayday said that in this case it seemed to be different: there was no sign of fatigue: it was a manufacturing defect

• Deforge: 39:06-39:19 "We actually found a deficiency in the bottom of the threaded boor section, we found a very sharp radius at the bottom of the threads, which is where the crack had profagated(?) from"

So this one didn't explain where the NW85 failure came from

• Deforge: 39:39-39:47 "Without knowing the why, you can't really take the appropriate corrective action and, as an investigator, that's frustrating"
• Deforge: 40:30-40:45 "We still don't know, actually, the root cause of the Northwest failure, but because of what we found with the second Air France failure, we needed to take corrective action to prevent similar failures from occurring."

Investigators recommend attaching special plugs to control module, in the event of another failure, the pieces will prevent rudder from moving too far in any direction WhisperToMe (talk) 19:58, 25 December 2012 (UTC)