Eddie sez:

Taken in isolation, this accident appears to be another unfortunate mishandling of Hazardous Materials, and there is no doubt that if it were not for the HAZMAT, the event would have never happened. But there is a case to be made that had the crew worked together more efficiently, they could have landed successfully. But their airline did not foster that kind of environment.
This was another incident in a series of 13, 11 of which pointed to a problem with the Crew Resource Management culture at Pan American World Airways at the time. They were able to reverse this culture and became one of the safest airlines in the world.
This cargo flight ended with the crew killed and the aircraft destroyed because of two factors: poor HAZMAT handling and poor CRM skills. Rules for carrying hazardous materials have been tightened considerably. Hidden in the reports, however, is the fact the crew could have survived had they landed at the first available airport or observed what we know today to be basic Crew Resource Management skills.
Philosophy for dealing with cabin fires has changed quite a bit since this crash and I don't mean to cast blame on the crew for not landing at the first available airport. But in drawing lessons from the loss, remember: speed is life. When you have a cabin fire, if you don't put the fire out in eight minutes or less you probably won't. If you don't get the airplane on the ground in fifteen minutes or less, you probably won't on your own terms. More about this: Cabin Fire/ Speed is Life.
The NTSB accident report would have you believe the crash was a direct result of the smoke in the cockpit making the airplane unflyable. I think there is enough evidence in the body of their report that shows that is not true. The airplane was made unflyable because of the uncoordinated actions of the flight engineer.
Everything here is from the references shown below, with a few comments in an alternate color.
Photo: N458PA, (www.baaa-acro.com)
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20180121
There are a few things to keep in mind when reading this NTSB accident report.
First, the occurred on November 3, 1973. The aviation community's consensus about cabin fires was to fight the fire immediately, land when you can. The industry's thought process would make a radical change — land as soon as possible, fight the fire if you can — after Air Canada 797, but that was still ten years into the future. More about this: Cabin Fire.
Second, Pan American World Airways at this time still embraced a culture that gave the captain total power and subordinate crewmembers were reluctant to challenge decisions. In that environment, I could see the second officer acting independently on things he considered purely flight engineering.
Finally, the NTSB report doesn't pay enough attention to the enormity of the task of flying this airplane without the yaw dampers. The report also implies cockpit visibility was so bad that frequencies couldn't be changed and perhaps the position of the speedbrake handle couldn't be seen either. But reading through the Cockpit Voice Recorder transcript seems to contradict that.
Note: the NTSB report uses local time for the body of the report, but Zulu time for the Cockpit Voice Recorder. I've converted everything to local time.
[NTSB Report, ¶1.1]
[NTSB Report, ¶2.11]
This "infers" runs contrary to the CVR, which shows the crew tested their radio altimeters just prior to requesting the single frequency and set their barometric altimeters after. It is more likely they wanted the single frequency as a precaution, not that they had limited cockpit visibility at the time.
[NTSB Report, p. 66 (Cockpit Voice Recorder)]
Time: 0919:45.0
I/P-3: I can't find a thing wrong back here
I/P-1 What's that?
I/P-3 I can't find anything wrong
I/P-1 Okay, uh, maybe it's in a package
I/P-3 Could be
The crew was unaware they were carrying HAZMAT and believed they were dealing with an electrical problem. But shutting electrical equipment down wasn't helping and the captain, at least, hypothesized that it wasn't an electrical problem after all, the flight engineer acknowledged.
[NTSB Report, ¶1.1]
The crew was asked if they wanted to declare an emergency and declined. There was a real reluctance back then to admit you had a problem you could not handle. Since Boston Center was giving them traffic priority and any assistance asked, this did not have an impact on the events.
[NTSB Report, p. 73 (Cockpit Voice Recorder)]
Time: 0924:58.5
I/P-3 Pressure altimeters
I/P-1 Twenty-nine seven-five Is okay
I/P-2 Set right
The crew was able to set their altimeters, about this time they spotted an airport on the ground, the confirmed three green landing gear lights, and started looking for the runway.
[NTSB Report, ¶1.1]
[NTSB Report, p. 75 (Cockpit Voice Recorder)]
Time: 0927:59.0
I/P-1 I don't smell that smoke as much now, there doesn't seem to be as much, does it?
I/P-3 Ah - ah, it doesn't seen to be as much
I/P-1 Huh?
I/P-3 It doesn't t seem to be as much
[NTSB Report, ¶1.1]
Most airlines at the time had believed smoke and fumes in the cockpit didn't require an immediate landing at the nearest suitable runway. In hindsight, however, we know that they had several suitable runways that would have allowed a safe landing before the airplane became unflyable.
[NTSB Report, p. 77 (Cockpit Voice Recorder)]
Time: 0930:17.5
I/P-3 That's worse. I don't see
I/P-1 It's getting worse?
I/P-3 Ah, I turned the, ah, equipment cooler off and that - - - that made it worse
I/P-1 All of a sudden it is getting worse in here
I/P-3 Tell ya what, turn the radar off, the Doppler's off - anything yuh don't need, let's shut em down
We find out (see the Analysis, below) that the flight engineer turned more than just the equipment cooler off.
[NTSB Report, ¶1.1]
At first I thought either the body of the report or the CVR transcript is wrong. With the former it is the captain who says shut everything down, with the latter it is the flight engineer. But looking at the listed causes, I am wondering if the NTSB bowed to political pressure from Pan American World Airways to paint the pilots in a positive light.
[NTSB Report, ¶2.11]
The report is trying to paint a picture of an airplane losing electrical systems as a result of some kind of fire while the cockpit visibility is going down to zero. Neither was true, as becomes evident in the Analysis, below. (The CVR stopped because the Flight Engineer took its electrical power away.)
[NTSB Report, p. 81 (Cockpit Voice Recorder)
Time: 0934:15.0
I/P-3 Okay, landing gear
I/P-1 Three green
I/P-2 Down three green
Even at this late stage, the crew did not have problems identifying the landing gear lights.
[NTSB Report, ¶1.1]
Carrying improperly packaged hazardous materials is a recipe for disaster, no doubt about it. Flying for a Part 121 airline should bring with it the necessary protocols to make that safe and the fact that sometimes doesn't happen should chasten those of us operating under "no fly" rules for HAZMAT; these things can kill you. More about this: HAZMAT.
This airplane did not crash because of the smoke and fumes, however. There is ample evidence that the crew was coping with the smoke in the cockpit and were well on their way to a successful emergency landing. What doomed them was poor Crew Resource Management. In particular, it was the flight engineer's actions that impacted the flyability of the aircraft without the captain's knowledge.
Every now and then I come away from reading an accident report wondering about the motivation behind the report. It should be to prevent recurrence. In this case, the focus needed to be on the HAZMAT and it was. So we got recommendations on how to change those procedures. There should also be an examination about the Boeing 707 smoke evacuation procedures and there was. So in both of these cases, the result of the report should be to make flying safer for everyone. But the report went out of its way to say the crew was debilitated by the smoke and just gives the actions of the flight engineer a mention in one sentence in the list of causes. Why? This was the eleventh crash of a Pan American Boeing 707, the ninth which was plausibly caused by pilot error. It could be there was intense political pressure from the well connected CEO of Pan American to downplay the role of the pilots in this one. The FAA did finally act, but it was six months after this crash, in which time there were two more.
[NTSB Report, ¶2.11]
[NTSB Report, ¶1.12 to 1.16]
[NTSB Report, ¶1.12 to 1.16]
[NTSB Report, ¶2.11]
[NTSB Report, ¶2.11]
The world of aviation has changed since this crash and very few would advocate overflying viable landing spots with an electrical problem causing smoke and fumes.
[NTSB Report, ¶2.14]
There is no doubt a cockpit filled with smoke will impact any crewmember's ability to think but these three were remarkably calm all the way to the end. Given the toxicological tests, I don't think the smoke was the primary cause of this accident.
[NTSB Report, ¶2.11]
The impact of the "external power" position was much more than just the yaw damper, but just losing the yaw damper alone made landing this airplane very difficult.
The report does not go into lateral control capability much deeper than this sentence, but it bears much more examination. The Boeing 707, without the yaw dampers, tends to Dutch roll. The aircraft becomes a handful, even under the calmest weather conditions. Unless you had trained to fly the airplane without the yaw dampers, your chances of landing safely without the yaw damper are greatly reduced. I've never flown an airplane with worse Dutch roll than the Air Force Boeing 707 (known as the C-135B and other variants) which did not have yaw dampers. The Air Force KC-135A was almost as bad. More about this: Stability and Control.
Eight of the ten Pan American Boeing 707 accidents that preceded this one had Crew Resource Management issues that involved an overbearing captain and perhaps an obsequious crew as the problem. The culture at Pan Am had not yet changed, but the make up of the crews were starting to. The captain on Pan Am 160 was 53 and had been with the company since 1951. The first officer was 34 and was hired in 1966. The flight engineer was 37 and was hired in 1967. A common survival technique with a very senior captain and younger cockpit crewmembers is to adopt the path of least resistance. For the first officer this means doing things the captain's way and only acting independently if given no other choice. A flight engineer has much more latitude, given that much of his or her responsibilities are outside the captain's field of view. There is no mention of the flight engineer coordinating these checklists or the changing of the essential bus power switch on the cockpit voice recorder.
[NTSB Report, ¶1.1]
[NTSB Report, ¶2.2(b)]
It appears that the person who wrote §2 of the NTSB report didn't talk to the person who wrote §1. The report's analysis discounts the high speed indicated by the recovered airspeed indicator, saying it was probably an error and that the aircraft may have stalled. The report's narrative cites "aeronautically qualified witnesses" that point to a pronounced Dutch roll. The Analysis also mentions "continuous heading change" at this point; in a Boeing 707 that also leads me to believe the crash was caused by a pronounced Dutch roll.
I would rewrite the findings as follows:
NTSB Aircraft Accident Report, AAR-74-16, Pan American World Airways, Inc., Boeing 707-321C, N458PA, Boston, Massachusetts, November 3, 1973.
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