Last night, at midnight, we landed a heavily laden airliner on a short runway in Connecticut. This airport is located in a shallow basin surrounded by wooded hills. A few years ago, another airline's crew clipped some tree tops landing on the same runway, at night and in bad weather. They damaged the plane and scared the heck out of the passengers, but were able to limp to the runway, despite both engines having ingested tree branches. It was a close call and a learning experience for every airline pilot. The weather conditions that night were atrocious with snow, low visibility, and strong winds. The kicker, though, was an extremely low altimeter setting which was falling rapidly. They began the instrument approach with an altimeter setting obtained from recorded weather that is updated at least once an hour, or more if needed. The setting being broadcast was higher than the actual barometric pressure at the time they began their approach. That in itself would not have been enough to cause contact with the trees, but as in most airline incidents or accidents, there are usually other factors at work.
It is known in the airline business as the "holes in the cheese" explanation. Imagine several slices of swiss cheese layered in a stack. Could something get through the stack from top to bottom? Yes, most probably it could. It is insidious. On that night, the crew began a non-precision approach (VOR approach) to the runway. When they leveled off at the minimum descent altitude (MDA) on the final approach segment, several things were conspiring against them:
1. The turbulence at low altitudes was substantial.
2. The barometric pressure was falling rapidly.
3. The Captain, the flying pilot, inadvertently descended two hundred feet below the minimum descent altitude.
Eventhough the altitude excursion was momentary, it was enough to put them into the trees. And, as the old axiom goes, the rest is history.
Over the years, I have heard fellow pilots make statements like, "What an idiot! I can't believe he/she did something like that. Where did they learn to fly?" OK, I admit to making a few statements like that when I was a young pilot and thought I knew more than the
old guy in the left seat. Usually, when I shot off my mouth in criticism of a fellow aviator, in a week-month-year I would do something equally bad or worse. I have learned to keep my mouth shut... tightly. No need to tempt the karma of
But by the Grace of God, there go I.So, last night, as the co-pilot (the flying pilot) was calling for landing gear and flaps over the final approach fix, I remembered...