The U.S. National Transportation Safety Board (NTSB) is investigating a Northwest Airlines flight that overshot its destination by 150 miles after pilots reportedly got into a “heated discussion.”
According to the Safety Board, “the crew stated they were in a heated discussion over airline policy and they lost situational awareness.” The NTSB said they plan to interview the cockpit crew and the plane’s cockpit voice recorder and flight data recorders will be analyzed. But air safety investigators will also look into whether pilot fatigue might also be involved.
The two unidentified pilots have been suspended from flying while the investigation runs its course, according to a Delta Air Lines spokesman. “We are cooperating with the FAA and NTSB in their investigation as well as conducting our own internal investigation,” the airline added.
Northwest Flight 188, en route from San Diego, CA with 144 passengers and a crew of five, passed over its destination of Minneapolis, MN at 37,000 feet just before 9 p.m. EDT Oct. 21. It eventually circled back and landed safely in Minneapolis.
Air traffic controllers in Denver and Minneapolis tried to raise the crew without success.
The Air National Guard had put fighter jets on alert at two locations, but did not intercept the errant airliner in the end.
In January 2008, two go! airlines regional pilots fell asleep for at least 18 minutes during a flight from Honolulu to Hilo, Hawaii. The plane passed its destination before controllers reached the pilots. The captain was later diagnosed with sleep apnea.
According to the NTSB, “when the flight was about 26 nautical miles southeast of the destination airport, the captain contacted the controller with an abbreviated call sign (“Ah HCF ten zero two”), and the controller asked if the flight crew was experiencing an emergency. The captain responded, “No, we must have missed a hand off or missed a call or something.” The controller then issued instructions for the flight to return to the destination airport, with which the flight crew complied. The flight arrived without further incident.
“The captain and first officer both reported to their company that they had unintentionally fallen asleep in flight. The fact that both pilots fell asleep during the midmorning hours, a time of day normally associated with wakefulness and rising alertness, indicates that both pilots were fatigued.
“The captain had undiagnosed severe obstructive sleep apnea, which was diagnosed during a medical evaluation shortly after this incident and for which symptoms (such as snoring) and risk factors (such as obesity) were present before the incident. This condition likely caused him to experience chronic daytime fatigue and contributed to his falling asleep during the incident flight,” the Safety Board determined.
The Oct. 21 event is the second time in less than a week that a cockpit crew employed by Delta was involved in a high-profile safety incident. On Oct. 19, a Delta Boeing 767- 332ER (N185DN) en route from Rio de Janeiro to Atlanta’s Hartsfield International (ATL) landed on a taxiway, rather than a runway. There were no injuries to any of the 182 passengers or 12 crewmembers aboard Flight 60.
The twin-jet landed on taxiway M after being cleared to land on Runway 27R. It is reported that a check airman was on the flight deck along with the captain and first officer. During cruise flight, the check airman became ill and was relocated to the cabin for the remainder of the flight. A medical emergency was declared and the company was notified by the cockpit crew. A determination was made to land at the scheduled destination.
Taxiway M is situated immediately to the north and parallel to runway 27R. The runway lights for 27R were illuminated; the localizer and approach lights for 27R were not turned on. Taxiway M was active but was clear of aircraft and ground vehicles at the time the aircraft landed. Both the runway and the taxiway are 11,890 feet long, according to an FAA spokesperson. The pilot and co-pilot have been “relieved of active flying pending the completion of the investigations,” said a Delta spokesman.
The airline incidents happened to coincide with the NTSB’s issuance of a ‘wake-up’ call to ground transport agencies about sleep apnea.
The Safety Board said commercial truck and bus drivers and merchant ship pilots should be screened for sleep apnea. The NTSB earlier this year made similar recommendations for airline pilots and train operators.
It recommended that the FAA revise the application for a medical certificate to include specific information about sleep apnea. The advisory calls for the FAA to “elicit specific information about any previous diagnosis of obstructive sleep apnea and about the presence of specific risk factors for that disorder.” It also asks the FAA to implement a program to identify pilots at high risk for obstructive sleep apnea and require that those pilots provide evidence through the medical certification process of having been appropriately evaluated and, if treatment is needed, effectively treated for that disorder before being granted unrestricted medical certification.