The NTSB continues to investigate last week's incident where the pilots flying Northwest Airlines Flight 188, an A320 carrying 144 passengers and five crew members, stopped communicating with air traffic control while in cruise and later overshot its destination airport by about 150 miles. The incident was on October 21, and on Monday October 26th, the NTSB released some information about the the flight. The following key events in the flight and the early investigation include a combination of information provided by the NTSB, Delta (which owns Northwest), and others:
- The incident occurred during Northwest Airlines Flight 188, a scheduled domestic airline flight from San Diego, CA to Minneapolis/St. Paul, MN.
- The flight crew stopped communicating with air traffic control while the aircraft was cruising at 37,000 feet.
- The two flight crew members were interviewed separately on Sunday October 25 for a total of about five hours
- Neither pilot has had any previous accident, incident, or violation.
- Neither pilot reported any ongoing medical condition.
- Both pilots stated that they were not fatigued and did not fall asleep or doze during the incident flight.
- Both pilots had a had a 19-hour layover in San Diego just prior to the incident flight.
- Both pilots said there was no heated argument during the incident flight.
- Both stated there was a distraction in the cockpit.
- The pilots said there was a concentrated period of discussion where they did not monitor the airplane or calls from air traffic control even though both stated they heard conversation on the radio. The discussion, which began during cruise, concerned a new flight crew scheduling system that was put in place after Northwest's recent merger with Delta.
- The pilots stated that at cruise altitude they were using cockpit speakers to listen to radio communications rather than their headsets.
- Neither pilot noticed messages that were sent by company dispatchers.
- Each pilot used a personal computer while they discussed the airline crew flight scheduling procedure.
- Delta Airlines, which has already suspended both pilots until the conclusion of the investigation, stated that using laptops or engaging in activity unrelated to the pilots' command of the aircraft during flight is strictly against the airline's flight deck policies and violations of that policy will result in termination.
- Both pilots said that they lost track of time.
- Neither pilot was aware of the airplane's position until a flight attendant called about five minutes before the scheduled landing time and asked about the aircraft's estimated time of arrival. It was at that point that the captain reviewed his instruments and realized that the airplane had passed the destination airport.
- Both pilots said there are no procedures for the flight attendants to check on the pilots during flight.
- When asked by air traffic control about the nature of their problem, they replied "just cockpit distraction" and "dealing with company issues".
- The NTSB planned to interview other company personnel, including the flight attendants, on Monday October 26th. They also plan to anlayze air traffic control communications.
- Preliminary data from the cockpit voice recorder (CVR) revealed that the recording was 30 minutes in length, and that it began during final approach and continued until the aircraft was at the gate, and that cockpit conversation were recorded by the crew's headset microphones (which were not used by the crew during at least part of the flight), but not by the cockpit area microphone. Also, part of the 30 minute recording included some period of time after the incident flight.
- The flight data recorder, which contains data from several hundred aircraft parameters, captured the entire flight, including the portion of flight where there was no radio communication from the flight crew. Investigators are examining the recorded parameters to see if any information regarding crew activity during the portion of flight where radio contact was lost can be obtained.
Issues Suggested by this EventA number questions remain about this incident, some of which can't be answered by the NTSB, the FAA, or the airlines involved. Most deal with the national security implications of this event.
Potential Safety and Security Issues:
Based on earlier reports, the aircraft was out of radio contact for well over an hour and flew over the Minneapolis area without being challenged by military aircraft. While the aircraft did not execute any maneuvers that would have been considered hostile, there were apparently no military aircraft in the air, or any other military assets on the ground to deal with the aircraft if it had been hijacked or otherwise no longer under the command of the flight crew.
Deficient Safety Databases: While some past incidents involving pilots overflying their destination or not responding to radio communications from the ground, there are no legal or regulatory requirements to report these events in publicly available aviation safety databases such as those managed by the NTSB and FAA. As a result, any estimate of the likelihood or frequency of these kinds of events will likely severely underestimate the risk to the public.
Cockpit Voice Recorder Technology: The cockpit voice recorder did not record the portion of the flight where the crew was out of radio contact. While the FAA allows airlines to install recorders with a 30 minute limit, there are models available with a two hour capacity, more than enough to have recorded for the entire time that the crew was not responding to the radio.
Sources for this Article:
NTSB,
Delta Air Lines,
Flightaware.com,
CNNOther ResourcesNTSB
Delta Airlines Statement 26 October 2009NTSB Investigation Update 26 October 2009
