I’ve been a fan of the National Geographic series Air Crash Investigations for a while. The series is shown worldwide with titles such as Mayday and Air Disasters. They usually do a great job recreating air disasters and following along as crash investigators try to piece together the events leading to an accident. Each episode is based solely on the final NTSB report. But what if the NTSB report is faulty? Such is the case with episode six of season 22 Terror Over Michigan.
The Terror Over Michigan episode recounts the near-fatal crash of TWA 841 on April 4, 1979. The first fifteen minutes of the episode provide a realistic recreation of what happened to the crew and their fourteen-year-old Boeing 727. While flying over Michigan, Captain Hoot Gibson noticed the plane banking to the right. The autopilot, which was on heading hold, tried to correct the right bank by turning the yoke to the left. Hoot felt a slight vibration. He disconnected the autopilot, and the plane continued rolling to the right. The plane went inverted and entered a spiral dive. Hoot managed to save the aircraft only after putting the landing gear down. That’s the setup. That’s also the beginning of a mystery. What caused TWA 841 to roll over and dive some 39,000 feet? The NTSB spent two years trying to solve that mystery. In the end, Boeing and the NTSB blamed the crew for the upset. That’s the story told in this episode. Unfortunately, the NTSB got it wrong.
After the recovery, the episode accurately portrays what happened after Hoot tried lowering flaps for landing. The actor portraying Hoot tells Scott Kenedy to raise the flaps. he then says “this is going to be our only approach.” In actuality, they made two approaches because they did not have three green gear down indications. I’ll give them a pass on this one for time considerations.
The incident aircraft had a missing number 7 slat. A report from Boeing indicated that it would require 70 gs of force for a slat locking mechanism to fail. What’s missing in this analysis is that there were signs that the locking mechanism showed a lack of wear. The slat was also misaligned. The slat didn’t lock into position because of the misalignment. The only thing holding it in place was hydraulic pressure and aerodynamic loads.
Now comes the circuit breaker and pilot action theory. Here the producers go down the same rabbit hole as did the investigators. Why would a pilot extend flaps at cruise? They show an investigator questioning a pilot (off the record) who tells them about a technique to lower flaps to two degrees but not extend the slats. The idea is that this somehow would improve performance (note: it doesn’t). First off, the procedure in question is a maintenance procedure. Maintenance technicians and not pilots wrote the Boeing report. Both the NTSB and ALPA questioned hundreds of Boeing 727 pilots, and they could not find a single pilot who knew of the procedure. The one pilot who did come forward much later did not know how to do the procedure and could not identify anyone who used it.
Next comes the erased CVR. They show Hoot at a hearing held eight days after the incident admitting that it was his routine to erase the CVR after every flight. The admission sounds pretty incriminating to today’s pilots, but it was routine at the time to erase the CVR. Additionally, the CVR only recorded the last thirty minutes of the flight and would not have recorded the upset. The producers also didn’t show the part where Hoot said he didn’t remember erasing the CVR on this particular flight. He had stated that he left everything in the cockpit just as it was to help investigators try and figure out what had happened. NTSB investigators also did not conduct any tests of the CVRs functionality even though they said they did in the report. The CVRs of older aircraft were not routinely tested and when they were, many were found to be not working properly. Lastly, the wiring to the CVR on this aircraft was severely damaged when the gear over-extended.
The NTSB was so convinced that Hoot erased the CVR to cover something up that they scheduled a televised hearing just eight days after the incident. The intent was to embarrass Hoot and point the finger at him and away from Boeing.
Rather than look for other possible explanations for the upset, investigators focused on the crew. They used the FDR analysis to prove that the crew tried the unauthorized procedure. There is a host of issues with how the NTSB did their flight test and how they incorrectly concluded that there was a match between the flight test aircraft and the upset aircraft. The reality is that there was no match. Not even close. Additionally, passenger statements about the severity of the vibration do not align with what passengers aboard the test aircraft experienced.
The NTSB theory only works if someone pushes the circuit breaker back in without the crew first raising the flaps. A passenger in a written statement said that she saw the flight engineer leave the cockpit to hand the meal trays to the flight attendant and that the upset happened within a minute of the flight engineer returning to the cockpit. That sequence of events was disproven in a separate hearing. That’s why you will not find any mention of circuit breakers in the final NTSB report. They only say “crew action.” So why did the producers decide to continue with this myth?
One of the most significant inaccuracies in both the NTSB report and this Air Crash Investigations episode is the idea that recovery was only possible after the slat tore away from the aircraft. Boeing’s own data indicated that the slat, if extended at 39,000 feet as suggested, would have been ripped from the plane at around 30,000 feet due to the aerodynamic loads. So why didn’t the crew recover much earlier in the dive? Flight tests proved that the Boeing 727 was perfectly flyable with the number 7 slat extended. NTSB investigators ran 118 simulator tests, and they could not get the aircraft to lose control unless the crew made no corrective action for seventeen seconds. To believe the NTSB theory, you have to accept that a flight crew would not take corrective action until the plane was in a 120-degree bank. The NTSBs answer was that the crew, all three of them, were spatially disoriented.
The slat broke into two pieces. Both pieces were found in the same farm field hundreds of feet apart. What are the chances of that happening if the slat broke in two at 30,000 feet? The facts suggest that the slat broke away from the aircraft at around five thousand feet or lower when the gear extended and hydraulic pressure was lost.
So what really happened? There is an alternate theory of what caused the TWA 841 upset. It involves the rudder. The alternate theory closely matches the physical evidence, passenger and crew statements, and FDR data. If you want to learn more about this, you should read the book Scapegoat.
I’m still a fan of the show, but the producers had information that indicated that what they were portraying was false. TWA supported the crew. Petitions for reconsideration were submitted but not acted upon by the NTSB. It’s time that the lies about the crew of TWA 841 end once and for all.
Steve Shaojie Tang
Finally, I have finished reading your masterful and well written book: Scapegoat. Thank you very much for your effort in recording this piece of history.
After I read your email “There is an alternate theory of what caused the TWA 841 upset. It involves the rudder.” I realized that your alternate theory may be the same as my recently discovered theory for the upset. After my carefully reading your book, the answer is Yes. They are the same. Your alternate theory is based on evidence, testimonies, interviews, logics, and etc., and My theory is from aircraft dynamics point of view to look at this incident with mathematical formular backing it up. My recent scientific discovery shows that yaw damper malfunction could trigger aircraft nonlinear rotational instability leading to large roll and yaw, and eventually loss of control.
The lower yaw damper fail flag of TWA 841 was observed after the upset. That is the indication that something was wrong with the yaw damper (or rudder). In my book, I have analyzed 18 aircraft accidents and incidents, including what you have mentioned in your book as TWA Flight 841 in 1979, UA Flight 585 in 1991, and USAir Flight 427 in 1994. Another similar incident case in my book is Boeing 737-236 Advanced G-BGJI Dutch Roll in 1995. This aircraft did not crash but safely landed after experiencing Dutch roll and MAYDAY CALL in the sky. Fortunately, this was a post-P6 maintenance check flight. There was no damage, no injury, and no passenger involved in this incident, meaning that no interest conflict in the following investigation. The FDR data from this B737 incident provided valuable data and evidence for me to analyze this incident against my theory. This case also provides significant evidence for what could happen due to yaw damper malfunction very similar to TWA 841.
I would like to propose a meeting (personally or remotely) with you to present and demonstrate my theory to you if you agree. I would like to offer a copy of my book: Nonlinear Instability and Inertial Coupling Effects – The Root Causes Leading to Aircraft Crashes, Land Vehicle Rollover, and Ship Capsizes, as a token of appreciation for the meeting.
Thank you again for your well documented book. I am looking forward to hearing from you.
Steve Shaojie Tang