The pilots of the Northwest Airlines Flight 188 that overflew Minneapolis on October 21 told NTSB investigators that a distraction in the cockpit of their Airbus A320 led to the incident, not a “heated discussion,” as reported by the Safety Board last Thursday. Both pilots, whom the NTSB interviewed for five hours combined, said they did not fall asleep, but rather engaged in a concentrated period of “discussion,” during which they did not monitor the airplane or calls from ATC even though both said they heard conversation on the radio. Neither pilot said he noticed messages sent by company dispatchers.
Air traffic control lost radio contact with the flight at 5:56 mountain daylight time, as Northwest Airlines Flight 188 cruised at 37,000 feet. The flight carried 144 passengers, the two pilots and three flight attendants from its departure airport, San Diego International. At 7:58 central daylight time, the airplane flew over the destination airport and continued northeast for some 150 miles. The MSP center controller reestablished communications with the crew at 8:14 pm CDT. At that time the crew requested a return to MSP.
When asked by ATC why they hadn’t responded to attempts to contact them, the pilots replied “just cockpit distraction” and “dealing with company issues.”
According to the pilots, whom the Safety Board interviewed separately, their discussion centered on a new monthly crew flight scheduling system put into place as a result of Northwest’s merger with Delta Air Lines. The pilots admitted to using their personal laptop computers and losing track of time. while they discussed the scheduling procedure. Company policy prohibits use of personal computers on the flight deck.
According to their statements, neither pilot knew of the airplane’s position until a flight attendant called about five minutes before their scheduled landing time to ask for their estimated time of arrival (ETA). According to the captain, at that point he looked at his primary flight display for an ETA and realized the airplane had passed MSP.
Although both pilots commuted to their base, they had just finished a 19-hour layover in San Diego before reporting for duty. Neither reported any fatigue.
Northwest hired the 53-year-old captain in 1985. Records show he has accumulated some 20,000 hours of total flight time and about 10,000 hours in the A320, some 7,000 of which he served as pilot in command. The airline hired the 54-year-old first officer in 1997. He had flown a total of about 11,000 hours and has accumulated some 5,000 hours on the A320.
Both pilots said they had never had an accident, incident or violation and neither pilot reported any ongoing medical conditions.
The Safety Board is continuing its interviews of the flight attendants and other company personnel. It has obtained and started the process of analyzing air traffic control communications. Preliminary data from the half-hour cockpit voice recording revealed that the cockpit area microphone channel didn’t work; however, the crew’s headset microphones recorded their conversations.
The CVR recording began during final approach, and continued while the aircraft sat at the gate. During the hours immediately following the incident flight, routine aircraft maintenance provided power to the CVR for a few minutes on several occasions, likely recording over several minutes of the flight.
However, the FDR captured data parameters from the entire flight, including the portion during which ATC lost contact with the flight crew. Investigators continue to examine the recorded parameters to determine whether or not they can obtain any more information regarding crew activity that portion of the flight.