There has been much discussion recently of the unfortunate Northwest Airlines crew that became distracted and flew 150 miles past their destination. The crew flew for 78 minutes without talking to air traffic controllers (ATC) and only became aware of their mistake when a flight attendant called to ask when they would arrive.
Northwest Airlines Flight 188 was enroute from San Diego to Minneapolis (MSP) when the incident occurred. While the Airbus A320 cruised at FL370 (37,000 feet), the crew apparently took out their laptop computers and became engrossed in a program that helped them submit bids for their monthly schedules. At some point, they missed a call from ATC telling them to change to the next sector’s frequency. When they missed the frequency change, they soon flew out of the range of the transmitter for the frequency they were listening to.
This is not unusual in itself. There have been several instances in my flying career in which I have suddenly realized that I have not heard an ATC transmission for some time. It seems to be especially common in the western states where there are fewer controllers covering larger areas, but it does happen in the east at times.
The standard procedure in the case of lost contact for ATC is to attempt to contact the aircraft on the emergency frequency, 121.5 MHZ. This is commonly referred to as the “guard” frequency. For years, the FAA has encouraged pilots to monitor this frequency on backup radios. In addition to providing an alternate method of ATC contact, it also allows pilots to listen for aircraft in distress that might not be heard by ground stations.
If the aircraft cannot be contacted on guard, ATC expects it to follow a predetermined route and altitude. When the pilots realize that they are out of contact, they normally take steps to find the appropriate ATC frequency for their area and reestablish contact.
In the case of the Northwest crew, the problem was that they were so engrossed in their computers that they never realized that they were out of contact. They should have realized that something was wrong as they drew closer to Minneapolis with a clearance from ATC to start their descent into the airport. Since the autopilot flew the airplane 150 miles past MSP without drawing their attention away from their computers, it is apparent that they were not paying much attention to the airplane or their location. This is why they are currently in trouble with the FAA.
It is tempting for pundits to say that the pilots should have no distractions in the cockpit. This is also unrealistic. A flight from San Diego to Minneapolis can take three to four hours depending on a number of variables such as aircraft speed, wind speed at cruising altitude, weather, and other air traffic. Some flights can be even longer. The aircraft that I currently fly has transcontinental range. A trip from the east coast to the west coast, slowed by westerly winds, can take as long as six hours.
Even though the flight might take several hours, the pilots are not constantly working. The busiest times of the flight are the takeoff and climb phase and the descent and landing phase. It typically takes about half an hour to take off from the airport and climb to cruising altitude. Similarly, it takes about half an hour to descend and make an approach and landing at the end of the trip. That leaves several hours of cruise flight in which the pilots have little to do except talk to ATC, monitor the autopilot’s flying, and monitor the aircraft systems. Since many of these flights are just one part of a long duty day, often with little rest, and are frequently made on “the back side of the clock,” when people are normally sleeping, the long periods of inactivity at cruise flight can easily lead to mind-numbing boredom and drowsiness.
Boredom and drowsiness are more than just an annoyance. In extreme cases, pilots can nod off to sleep. In other cases, this fatigue can negatively affect the ability of pilots to perform their jobs. Studies in pilot fatigue show that the effects of pilot fatigue can cause slow reaction times and lead to degraded decision making. To keep themselves sharp, it is not uncommon for pilots to bring distractions into the cockpit.
I have never seen any pilot use a laptop computer in flight, but other distractions are more common. Some pilots bring reading material, DVD or MP3 players, crossword puzzles or Sudoku, or paperwork such as schedule bids or chart revisions. Even if pilots bring nothing extra into the cockpit, most airliners are equipped with an ADF radio that can pick up commercial AM radio broadcasts. Having something to focus on actually helps pilots keep their minds sharp and reduce fatigue on long flights.
Try to imagine sitting in a small room with another person for four hours. You cannot get up and walk around. You can’t watch television. You can’t take a nap. You can’t do anything except monitor a few screens and gauges or talk to your seatmate. Now imagine that you do the same thing several times a day and as many as twenty days a month. That situation is similar to sitting in a cockpit at cruise for an airline pilot.
To the confinement is added the problem of airline crew schedules. As airlines lay off (furlough) their employees, the remaining crews fly tougher schedules. The FAA allows airlines to schedule their crews with as little as eight hours of rest. This means that the crew has only eight hours to travel from the airport to the hotel, eat, sleep, shower, dress, and travel back to the airport to start their next day of flying. While airline crews are limited to eight hours of scheduled flying per day, their duty day can last as long as sixteen hours (unless further limited by union contract or company policy).
These problems are compounded by jet lag as the crew crosses multiple time zones (in both directions) and the fact that a crew can have their schedule alternate between extremely early and late flights, which makes it difficult for one’s body to adjust and causes sleep problems. The FAA and airlines would take a dim view of pilots reporting to work after drinking alcohol, but the Federal Aviation Regulations regarding crew rest and airline scheduling policies ensure that many crews report to work with the physiological equivalent of several stiff drinks.
The FAA investigation may ultimately reveal that some or all of these factors were involved in the Northwest crew’s problems. Regardless of the circumstances of this particular flight, the issue of fatigue and boredom is one that many crews face on a daily basis in the real world of jet aviation. Congress and the FAA should not hastily make rules to ban all diversions from the cockpit in cruise flight. Such a rule would be unenforceable and unnecessary. If puzzles and electronic devices are banned from the cockpit, there’s always the ADF.
November 4, 2009