When, back in October 2009, a Northwest Airlines flight went AWOL over Minnesota, dropping out of radio contact and wandering off course. What happened was shocking and unacceptable, everyone felt. It was embarrassing to pilots everywhere. Moreover, they had a difficult time imagining how two professional airmen could allow such a bizarre thing to happen. How was it even possible?
The problem was, all we had to go on was the media’s condensed presentation of the event: Two pilots, focused on their laptop computers, lost track of where they were and overshot their destination.
But was it really that simple?
Imagine, for a moment, the following scenario:
Flight 188 is en route from San Diego to Minneapolis, somewhere around Denver, when a flight attendant calls the cockpit to let the captain know his crew meal is ready. The captain takes his tray, and uses the opportunity to step out and use the lavatory.
While he is out of the cockpit, the first officer receives a call from air traffic control, asking him to contact the next sector on a new frequency.
The first officer acknowledges by repeating the information back to the controller, then setting the new frequency into one of the VHF radios.
Radio frequencies are at least five digits long (often six digits overseas), and as you might expect, it’s not unheard of for a pilot to accidentally transpose a couple of numbers. This happens from time to time and is seldom if ever dangerous.
The situation is normally corrected after a minute or two, often because the incorrect frequency is completely silent: The crew gets no response, and there is no chatter from controllers or other pilots.
Aboard Flight 188, the first officer mixes up the numbers and dials in a frequency for Winnipeg, Canada, instead of Denver. Let’s call this Factor 1.
Winnipeg is hundreds of miles away, and controllers there do not hear him. They are unable to acknowledge his call or correct his error. At the same time, however, Flight 188 is at a high enough altitude that transmissions from other aircraft under Winnipeg’s control are clearly audible in the cockpit. Thus there is plenty of chatter coming over the radio. This leads the pilot to believe he is on the correct frequency. Let’s call this Factor 2.
A short time later the captain returns. He too hears the radio chatter and has no reason to think anything is wrong. Factor 3.
When a pilot comes back from a restroom break, it is customary for the other pilot to brief him of any changes, such as a new altitude or heading assignment, revisions to the routing, radio frequency changes, and so forth. In this instance, nothing is said. The captain is not told of the frequency change, or about the fact that nobody acknowledged the first officer’s call. This would be Factor 4.
Neither does the first officer, having received no reply, make a second attempt to contact ATC. Factor 5.
Why he neglects to do these things isn’t clear, but neither is it shocking. After all, few things are more routine than dialing in a new radio frequency and, as we say, “checking in.” This can happen dozens of time over the course of a flight, and failure to get a response from ATC on the first call is not uncommon, especially when a frequency is busy.
Occasionally, when the chatter is unusually heavy, you wait for them to contact you. In addition, the first officer is distracted by the commotion and security rigmarole required when opening and closing the flight deck door. It’s possible that he’s simply forgotten. Factors 6, 7 and 8.
Soon thereafter, back on the correct frequency, Denver Center is trying to get hold of Flight 188, wondering why it never checked in. They call many times, to no avail. Minutes later, there is a shift change at the facility.
For reasons unknown, the new controller is not told about the failure to reach Flight 188. Had he known about this, there are steps he could have taken to help track down the wayward flight. But he didn’t. Factor 9.
As they fly along, unknowingly out of contact, the captain and first officer then get into a long discussion about the airline’s new scheduling system for pilots. The first officer takes out his laptop and gives the captain a short tutorial on how to bid his monthly schedule. The captain takes his computer out as well. Neither computer is on for more than five minutes, but clearly both crew members are distracted. Factor 10.
On they fly, still out of contact with ATC. Worsening matters is a hundred-knot tailwind, and the fact that the pilots have their navigational screens set to the highest mileage range, which compresses the distances and waypoints and makes any deviation less noticeable. Factor 11.
At one point Northwest attempts to contact the plane via the on-board datalink system known as ACARS. On some aircraft, an incoming ACARS message is indicated by an audible chime. But on this one there is just a small light, and it stays illuminated for only 30 seconds. The message goes unnoticed. Factor 12.
Eventually a flight attendant calls on the interphone to ask about their arrival time. At this point the flight is directly over Minneapolis.
Depending on traffic, runway use, etc., arrival patterns can sometimes take a flight several miles beyond its destination before turning back again, but this is different. The crew realizes something is wrong. They track down a Minneapolis frequency, establish contact, and begin to receive instructions for landing. ATC is naturally suspicious, and puts the aircraft through a long series of turns to be certain the pilots haven’t been hijacked and are in full control. Finally Flight 188 is cleared to land.
When the Airbus gets to the gate, the FAA and FBI are among those waiting.
This scenario is based on a secondhand account written by a pilot who happens to be a friend of Flight 188’s captain.
In other words, laptops were only part of what went wrong. This was more than a pair of pilots zoning out under the glow of their computers. It was something less overt: a combination of small errors and oversights, not all of them of the crew’s doing, creating a loss of what a pilot calls “situational awareness.”
The pilots had their FAA certificates stripped through emergency revocation almost immediately, prior to any formal investigation. Reportedly, not everybody at the FAA thought this was the best of course of action, but pressure to do so came all the way from the White House. The media firestorm dictated that somebody had to be punished, and fast.