Pilot: Clues amid mystery of Colombia plane crash

Editor’s Note: Les Abend is a Boeing 777 captain for a major airline with 31 years of flying experience. He is a CNN aviation analyst and senior contributor to Flying magazine. The opinions expressed in this commentary are solely those of the author.

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Les Abend: Little known about why plane crashed in Colombia but it's possible to offer some informed speculation

He says "mayday" call could have indicated onboard emergency; weather, terrain could have made situation worse

CNN  — 

Any airplane crash is a tragedy, but the accident outside Medellin, Colombia, that claimed the lives of revered young athletes on Tuesday is especially difficult to comprehend. Members of Brazil’s Chapecoense soccer team, along with coaches, guests and journalists were among those who perished, and Brazil will mourn this terrible loss.

Six people survived, and most would consider survivors part of a miracle, but they are also among the clues in the investigation process. More on that later, but first, what we know:

The chartered flight hit the ground in an area near Rionegro, Colombia, about a 45-minute drive from Medellin, the plane’s destination. The flight had departed Santa Cruz, Bolivia, carrying 77. The airplane was an Avro RJ85, a four-engine jet, which is a variation on the former British Aerospace BAE-146 of the 1990s.

Investigators said the cockpit voice recorder and the digital flight data recorder have been recovered. Although these “black boxes” contain crucial data, they are only two pieces in the jigsaw puzzle of the accident investigation. Let me stress that airplane accidents often involve multiple factors that can’t always be determined directly from onboard technology.

At this point, we can engage in some educated speculation, but it is only that, as many of the details are unknown. And never is just one factor the absolute cause of the crash.

For example, it has been reported that a “mayday” had been declared, though the nature of the emergency has not been disclosed. It is possible the crew was addressing a mechanical issue. Colombia is a challenging country to fly into because of mountainous terrain that surrounds many of the airports.

If crew members became distracted during an emergency, perhaps as they completed a required checklist, they may have lost their situational awareness and allowed the airplane to descend too low for the terrain. Again, speculation, but a circumstance that has occurred with other accidents.

The pilots may also have been attempting to divert to the Rionegro airport as a result of their (as yet unknown) emergency situation but became overwhelmed. If there was smoke in the cockpit from an unknown source it could be disorientating and debilitating.

The weather was reported to have been marginal, with thunderstorms, rain and fog at the time of the crash. Certainly the outside environment could have been a factor if it was combined with the stress of attending to an emergency event. Or the weather itself could have caused problems with controlling the aircraft if the flight was flown into an area of severe turbulence from thunderstorms.

Another possible factor: Pilots flying for charter operations are sometimes lower on the experience scale compared with mainstream airline pilots. This doesn’t make them any less qualified, just potentially less experienced in dealing with situations involving emergencies, weather, or challenging terrain than a veteran airline pilot.

It’s a truth of the airline industry that the less experienced pilot often accepts employment with a lower-paying operation as a pseudo-internship to log flight hours and climb the stairs up to a job with the major airlines.

The crash site photos of this tragedy tell some of the story. Because large pieces of the airplane are visible, it appears the impact with the ground may have been at a lower speed (small fragments indicate a high-speed event). The crew may have slowed the airplane in an attempt to begin the approach and landing process.

The fact that survivors were found among the wreckage is further evidence the airplane may have been flying slower. In contrast, most high-speed crashes result in blunt trauma fatalities with no survivors. The location of the survivors may give investigators clues about what angle and speed the airplane impacted the ground.

Again, it will be awhile before we know exactly what happened.

In the meantime, we’ll have to wait for the investigative process to be completed while we mourn Brazil’s tragic loss.