On Monday July 25 Delta flight 9923 from New York JFK to Accra, Ghana headed out over the Atlantic and then diverted back due to fuel issues. The flight had already been delayed from the day before, reportedly due to a sick pilot, and was operated as a special extra section.
However the second attempt at the flight took a turn for the worse. About two and a half hours out over the Atlantic the captain announced that the Boeing 767 had a fuel issue, and that they would have to return to New York. Emergency crews met the plane on arrival.
A cabin crew member shared with passengers that the plane had a fuel leak. A pilot had been inspecting the wing through the window from inside the cabin prior to departure, leading passengers to believe there was a known maintenance issue prior at the time. In total the flight took 5 hours to depart and make it back to New York.
A passenger – Xiaomanyc with 5 million YouTube subscribers – shared just how scary the experience was to be over water and learn that the plane might not have enough fuel. He says they were told they believed they had two hours to make it back to New York, though I wonder if that was a misunderstanding and they expected to take about two hours to get back.
On arrival, emergency vehicles – “fire trucks and ambulances” – responded to the flight’s return. In the video the captain explains that the aircraft had a “fuel imbalance” in the form of a “huge disparity” in fuel levels between the aircraft’s two fuel tanks which couldn’t be resolved.
The Boeing 767 has left and right main tanks, and a center auxiliary tank. The aircraft’s ‘fuel config’ light would have turned on and an advisory FUEL CONFIG message displayed.
This may be caused by a fuel leak, which would also be indicated by less fuel remaining than expected or by excessive fuel flow (greater fuel pump output pressure in the lower balance tank). It could also be caused by engine damage – or just a notification system failure.
Assuming the engines didn’t seem to be damaged, pilots would have attempted to balance the fuel by opening the crossfeed valves and turning off the fuel pump switches for the main tank with the lowest quantity.
Now, a plane can continue to operate with a fuel imbalance. However two issues present themselves,
- Frequently operating this way adds stress to the airframe, reducing the plane’s useful life
- The imbalance may cause increased trim drag (lateral trim would be neeeded to maintain level wings) and therefore higher fuel consumption – so the aircraft would need more fuel than anticipated to reach its destination. Even if the plane technically still carried enough, pilots could project to draw down fuel below minimums, necessitating a diversion.
It’s not clear just how close to out of fuel this aircraft was. I aske Delta for comment on the incident but they did not share detailed specifics. Instead they offered,
Delta flight DL9923 on July 25, enroute from New York-JFK to Accra, returned to New York-JFK out of an abundance of caution due to operational reasons. The flight landed safely and customers deplaned as normal. The safety and security of Delta’s passengers and crew is Delta’s number one priority. Delta’s customer support teams at JFK were engaged on the ground to assist affected customers and Delta deeply apologizes for the inconvenience and delay of their planned travel.
Fortunately the pilots responded properly and got everyone back safely. And ultimately another extra section, Delta 9887, took passengers from New York to Accra on Tuesday. The occurrence aircraft was fixed and operated a flgiht to Atlanta two days after the incident, on Wednesday afternoon.