From the Det News: Preliminary report on the cause of the Hatch accident

The Detroit News tonight posted a small story on the NTSB's preliminary report into the crash that killed Austin Hatch's father and step mother. You can find it here:

The story mentions that a flight instructor from Indianapolis is speculating that the cause could have been a stall following a missed approach. From my experience, this is as good an explanation at this point as any, though the NTSB will continue to examine all of the available evidence before issuing its final report. It may yet turn out to be something other than the CFI's best guess.

For those of you who are not pilots, a "missed approach" is a procedure, documented in what are called Standard Terminal Arrival Routes, or STARs, that a pilot follows when his initial attempt to land at an airport under Instrument Flight Rules (IFR) is aborted due to weather, other traffic, etc. We'll often called these STARs "approach plates", because in printed form, they are about 5"x7" and fit a board (or "plate") that can be strapped to the leg of the pilot or mounted on the control yoke.

A stall occurs when the smooth ("laminar") flow of air begins to separate from the top of the wing, as shown below:

The angle between the "relative wind" and an imaginary line that runs from the wing's leading edge to its farthest back point is known as the "Angle of Attack". When the Critical Angle is reached, lift abruptly begins to decrease.

"Relative wind" is also important to understand, because it is the angle between the wing's imaginary front-to-back line (called the "chord") and the direction of the on-coming air relative to the wing.

So what does all of this mean for the instructor's speculated cause of the crash?

When a pilot executes a Missed Approach Procedure, she/he transitions from a descent to land to - usually - a climbing turn toward a fixed point called a "navigation fix". It is during this time, low and slow, that the pilot is vulnerable to a stall. That is because the Angle of Attack increases during a turn. Additionally, the aircraft is executing a climb, which also means a "nose-high" attitude and higher Angle of Attack. Assuming that Dr. Hatch executed the MAP successfully, later turns, possibly while descending, could have caused the same conditions.

When I learned to fly - both for my Private Pilot and, later, my Instrument rating - I, like all pilots, practiced stalls with both a clear view of the horizon and "under the hood" (the student's view of the world outside the aircraft obscured by special glasses or an adjustable hood that let me see the instrument panel, but nothing else). An experienced pilot, Dr. Hatch practiced them as well. It is essential for a pilot to recognize the onset of a stall and to correct the aircraft's pitch, roll, power and airspeed to avoid it.

All stall recoveries, though, take time at some loss of altitude. The standard by which pilots are judged during training is that not more than 50 ft. of altitude can be lost during a stall recovery. In "real world" IFR conditions and close to the ground, such as Dr. Hatch found himself last weekend, there just isn't much margin for error. He had to detect the onset (which is aided by a stall warning horn), mentally process the correct situation he was in, determine the appropriate response, and fly the recovery in a split second. Unless he had recently been practicing stalls, either on his own or with an instructor, chances are pretty good that his skills were rusty. That's not an indictment of his skills as a pilot. Most private pilots, myself included, are similarly one unfortunate chain of events from the same outcome.

I pointed out in an earlier thread that I am constantly aware that, "There, but for the grace of God, go I." Hopefully, if anything positive can come from this, it is an increasing awareness among private pilots like me that we must remain vigilant and continue to practice, hoping for the best, but fearing the worst.