The National Transportation Safety Board (NTSB) recently published a conclusive report on Delta Air Lines Flight 211, which encountered an anomalous autopilot issue during its flight in July 2022.
In 2022, Delta Air Lines Flight 211 was a return leg from Prague (PRG) to New York (JFK) before the flight number was reassigned to Delta’s South Africa services.
The flight had 221 passengers and 12 crew members onboard and departed from Prague at around 14:00 CEST. The journey between the two cities took around 9 hours and was operated by Delta’s 30-year-old Boeing 767-300 with registration number N181DN.
During Delta Air Lines Flight 211, cabin crew members reported flooding in the mid-cabin and forward-left lavatories while passing over southern Greenland.
Although an out-of-service aircraft is usually not an emergency, as the flight progressed, the flight deck crew noticed that the aircraft’s autopilot had disconnected and that there were roll control issues.
When the team attempted to fix the problem, they found that they couldn’t reconnect any of the aircraft’s three autopilots, and the aircraft was gradually drifting right.
Delta 767 Autopilot Incident
During Delta Air Lines Flight 211 in 2022, which flew from Prague to New York, issues arose when flooding was reported by cabin crew members in the mid-cabin and forward-left lavatories. Additionally, the autopilot disconnected, and there were concerns with the aircraft’s roll control.
The flight crew declared an emergency and began diverting to Gander Airport while attempting to regain control of the aircraft. They felt a slight jolt as they descended through 12,000 ft and were able to regain control of the flight. The emergency was cancelled, and the aircraft landed an hour later than scheduled at JFK. After landing, the aircraft was sent to Delta Air Line’s TechOps for repairs.
Repairs included the autopilot and roll control inspections, the grey water drain masts replacement, and a seal close to the aileron centring and trim mechanism. The aircraft was cleared for service on July 12th, reported SimpleFlying
NTSB Report
According to the NTSB’s report published on Friday, the limited flight controls and autopilot error on Delta Air Lines Flight 211 can be traced back to the faulty toilets.
Despite the older age of the aircraft, the report suggests that human error was the primary cause of the incident. Delta Air Lines’ maintenance, repair, and overhaul (MRO) personnel found that the forward and aft toilets’ drain mast heater circuit breakers had been left open during prior maintenance in June 2022.
The NTSB concluded that this led to the formation of ice in the forward drain mast, improper wastewater flow into the main landing gear wheel well, and ice formation on one or more aileron system components. Delta Air Lines replaced the elements and confirmed normal functioning during testing.
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