SWA 737 Max-8 'Dutch Roll' Incident

Quick field report from Columbus OH.
LINKS:

Theme: "Weightless" Aram Bedrosian

[nerdtalker]

The fact that voice recorders are constantly getting overwritten in all these incidents lately, in the age of NAND in the TBs taking up virtually minuscule amounts of mass and volume, is absolutely ridiculous.

[idontwntahandle]

I had some incredible instructors in the USAF. When you do these breakdowns it really reminds me of the quality airmanship passed down to us and expected by us. I have immense respect for instructors like yourself. I always enjoy the nostalgia.

[russell]

Was at the Columbus Airshow today and I thought that voice sounded familiar. You and all the announcers did a great job today.

[NCrdwlf]

As a flight attendant of 28 years, responsible for the 737 in all of its iterations, thank you for this . I guarantee we will hear nothing of this in our annual training . I will share it with my co hearts . A very well done presentation.

[RamJetJockey]

One of the things we do in simulator training is a Dutch Roll demo at high altitude. We disarm the Yaw Damper and turn off the autopilot. The results of displacing the rudder in this condition causes a Dutch Roll that can be really dramatic in swept wing jets and hard to recover. Props to the pilots in this case who managed to recover from this incident.

[HisDudeness]

I love aviation and I know just enough to be dangerous to humanity.

However, I am an engineer and spent my entire career in nuclear power, which which is complex .

I watch your channel frequently. You do ask for input on occasion, but this video was very much different.

You did something that is rare on YouTube. I am extremely impressed. I don’t know how many people noticed. You stated when you did not have details of the max rotor system and asked for help from the professionals that watch your channel. You did not bloviate. You’re confident enough that you knew your limits and asked for data.

That requires maturity, common sense, and confidence. I salute you, sir.

I got to add a dig. Go Navy.

[paulhavis]

I only flew the 737 100/200 (guppy series) for PEOPLExpress in the early 80s. I was dispatched once from Florida to Newark with a YAW DAMPER INOP MEL. Holy shit! Even though we were restricted to a lower altitude by the MEL, the passengers in the back sure knew it was not a normal flight by the tail swishing around. I couldn’t feel it up front at cruise altitude, but I REALLY noticed the difference when I was hand flying and we went skidding right through the final approach course… and I realized that because of inop Yaw Damper I had to use the rudder pedals just like in a Cessna, which 737 pilots never do. It was an eye opening experience.

[SteamCrane]

Watching this, I realized what a great FAA Administrator Juan would be. Knowledgeable, committed, and truly focused on getting things right. Juan wouldn't need to fire the incompetent ones, they would just quit out of fear.

[UnshavenStatue]

"On Jun 13th 2024 The Aviation Herald learned that two ribs, that the stand by PCU is being mounted to, were damaged as well as the mounts of the stand by actuator. A temporary repair was done in Oakland replacing the damaged PCU, the aircraft was then ferried to Everett to replace the damaged ribs."

[TheDesertRat]

Old enough to have flown a C141. Lol. Didn't fly it, but I jumped out of one a few times in airborne school. I think my class was one of the last to do that. I remember it was a long shuffle back to the jump door. All the way! De Oppresso Liber!

[StigAviation]

This is a very strange occurrence, I’ve been doing maintenance on the 737 NG for about 25 years at this point, as well as the max from it’s beginning stages when we got it at our fleet. The system is identical in both aircraft. The fact that the standby power control unit was causing this issue or was said to cause this issue is very interesting to me. The standby Rudder power control unit it gets alternate hydraulic power from the standby hydraulic pump. The standby hydraulic pump supplies power when system A or system B flight control switch is in the standby Rudder position. Also interesting thing to note is that the standby Rudder shut off valve, on the standby hydraulic system module controls the pressure to the standby rudder power control unit. The system works automatically when the standby pump supplies pressure to the PCU. My best guess is that if the PCU was actually the thing that was causing the Dutch roll, it might’ve been a malfunction within the standby rudder shut off valve where it was sending uncontrolled fluid to the unit. But that’s very unlikely, forgive my assumption, but it seems to me that this might have been induced by human error and in doing so trying to correct themselves caused the Dutch roll. But once again it’s an assumption wait for the NTSB report.

[FutureSystem]

Thanks Juan.
As a retired 30k hour heavy jet captain, I find it absolutely bizarre that cockpit voice recorders have not been able to record literally many tens of hours, and should have been able to do this for many years. 30 mins, or in this case just two hours is ridiculous. Even my phone can do that- it’s inexcusable.

[fractaljack]

Never have I seen modified charades so expertly explain the physics of a Dutch roll. Well done, Juan!⚡👊🏼⚡

[cloudstreetjourneys]

Hey Juan. I thoroughly enjoy your videos and all the in-depth research you do. I just watched the video about the 737rudder issue that happened recently. I am a tech instructor for both the A-320 and B737 Max for an airline. To answer your question, the Max uses the same rudder control system as the NG. Incidentally, after the RSEP (Rudder System Enhancement Program) which was mandated in the early 2000's, a new main PCU was installed (I did a few of them while I was turning wrenches). That said, the classics then had the same type of rudder system as the NG and the Max after the modification was incorporated (RSEP). The Force Fight Monitor was a big part of this upgrade. The Force Fight Monitor is installed in the main rudder PCU and once it detects a difference of 3600 psi for a minimum of 5 seconds (one system pulling one way while the other system pulls the other way), it will automatically turn on the standby hydraulic pump and activate the standby PCU which will control the rudder. One disclaimer is that I DO NOT work for the airline that had the problem but am aware of it via the news and your channel. Hope this helps and keep your awesome content coming!

[georgemartin]

Saw the headline but decided to just wait until Juan talked about it instead of looking then.

[johnwatson]

It is a problem with the Rudder Yaw Damper. Had it happen to me on a B737-500 over Palms Springs at FL330 enroute from LAX to CLE. Lost 6000' before getting aircraft back to straight and level. Thank God for my Navy aerobatic training.

[JamesJoseph-uy]

For all you fellow aviation geeks out there, according to William Cook in his book The Road to the 707, the yaw damper was invented by Ed Pfafman, an engineer at Boeing during the flight testing of the XB-47 - the USAF's first swept wing jet bomber. The test pilots noted a continuing Dutch Roll in '47 and Ed came up with a solution. Brilliant guy. A yaw damper has been standard equipment on swept wing jets ever since.

[benmccullough]

Love your content Juan. I'm an ARFF firefighter for an airport in Ohio and happened across your channel shortly after I started. Love the videos you do on aircraft incidents since it is something I could possibly be involved in responding to..

[SI-lgvp]

I experienced a total loss of the PCU in a SWA 737-200 on a flight from SAN to PHX. At touch down we lost all hydraulics of the A, B, and Stby system. They claimed that it was not possible to loose all hydraulics through the PCU, but it did occur. This occurred around the time of the crash of the United 737 that crashed in Colorado Springs from a PCU fault.

[charlestosi]

Brilliant, instructive and crystal clear examination of the phenomenon. Thanks again, Juan. You cranked it out of the park, once again.