Delta 767 Flooding Lavatories Disrupt Autopilots?

By Spyros Georgilidakis | August 13, 2022

The crew of a Delta Air Lines 767 found that they could not use any of their autopilots after some of the aircraft’s lavatories flooded!

This incident happened over a month ago, on Thursday the 7th of July. It involved Delta Airlines flight DL-211. This is a daily service, departing at 1:45 pm local time, from Prague Vaclav Havel Airport (LKPR) in Czechia. Its destination is New York’s John F. Kennedy International Airport (KLFK) in the United States. There were 133 people on board the aircraft.

Delta 767 Flooding Lavatories Disrupt Autopilots?
Photo: Jan Rosolino

The flight made a routine departure from Czechia, making its way northeast. The Delta 767 widebody was close to the south tip of Greenland when there was flooding in the lavatories that are towards the middle of the cabin. Shortly afterwards, there was similar flooding in the aircraft’s forward left lavatory.


Delta 767 Control Problem Trumps The Lavatories

Then in a seemingly unrelated development to the aircraft’s lavatories, the autopilot that the Delta 767 pilots were using disconnected. 767s have three autopilots, with the crew trying each one in turn. No autopilot would remain engaged. Afterward, the situation got even worse when the aircraft seemed to drift to the right. For a time, correcting the aircraft’s course was reportedly impossible.

Photo: Miguel Angel Sanz

The Delta 767 flight crew was no longer dealing with a mere flooding of their lavatories. They reported jammed flight controls to their dispatch, working the relevant checklist. The crew then declared an emergency, deciding on a diversion to Gander International Airport (CYQX) in Newfoundland, Canada.

But as the crew got closer to Gander International, they found that they no longer had an issue with their flight controls. They then terminated their emergency and re-designated their diversion airport to Boston’s Logan International Airport (KBOS) in the United States. They also descended to 11,000 feet in the process.

Photo: Ramon Kagie


A Clue As To The Cause?

But some time after this, the crew realized that even at this altitude, they could reach their original destination (JFK) safely. So about four hours and fifteen minutes after the flooding of its lavatories, the Delta 767 touched down safely on JFK’s runway 04. But what could have caused all this?

The investigation on this matter is still ongoing. However, Canada’s Transportation Safety Board (TSB) has reported on the maintenance that the airline performed after the incident. Relating to the issue with the lavatories, Delta engineers changed both grey water drain masts on the 767. They also replaced a seal in the left wheel-well canted pressure deck.

Delta 767 Flooding Lavatories Disrupt Autopilots?
The incident aircraft. Photo: Riik@mctr, CC BY-SA 2.0

This device is above the aileron feel centering and trim mechanism. Ground crews also inspected the aileron/roll controls as well as the autopilot. This author is not an airline engineer or a commercial pilot. So we will have to wait for the final report, to see how the water drain masts, the seal and the aileron feel centering and trim mechanisms combined, to make this event possible.

We do know that with its lavatories now fixed, the Delta 767 is now back in regular service. This is a 767-300ER model, with tail number N181DN. It was just under 30 years old at the time of the incident and has spent its entire “career” in the hands of Delta Air Lines.


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