Avoid 'Expectation Bias' In Critical Situations

“Money is the the root of all evil.” Did you notice the extra “the” in that sentence?

Expectation Bias led us to expect the same familiar phrase. This concept can apply in many aviation situations such as the following:

Coming in from the south and landing east at Flying Cloud, you would expect to land on the long SOUTH parallel, 10R.

However, tower clears you to land on 10L, the NORTH parallel. You read back “Cleared to land 10L” but then proceed to land on 10R. This has actually happened and the pilot was even aware of the clearance to land on the left runway.

But Expectation Bias can be a strong force that can pull you into its grasp.

A strong contributor to Expectation Bias is familiarity. If you are accustomed to always getting a clearance to cross a runway on your taxi to the runup pad at your home airport, what can easily happen if you did not receive that clearance this particular time? You clear right and left and can easily cross the runway without clearance.

Or you just flew six flights in two days departing to the west.

The winds change and you turn the same way you have been and end up being Wrong Way Corrigan. It’s frighteningly easy for these kinds of things to happen.

Another example that stung many professional pilots was the descent clearances into MSP years ago that were always to 10,000 feet.

Then the arrivals changed and pilots were to descend to 11,000 feet. Expectation Bias bit hard and a great many pilots faced potential violations for continuing down to 10,000 feet even though they had read back 11,000 feet.

This reminds me of the time I was pulling into the chocks in a Mooney at the FAA Technical Center in Atlantic City in the early ‘80s. Glancing up for a moment, a Dash 8 popped out of the overcast in a descending turn while test flying a microwave landing system curved approach. As we did the shutdown checklist, fire trucks started whizzing by because the Dash landed gear up! Under the highly experienced pilot’s picture in the newspaper the next day, the caption read, “I thought the gear was down!” When we do something repeatedly, even hundreds of times, it is not hard to EXPECT the task to be completed when it isn’t. Being aware of Expectation Bias can help you avoid its trap. Happy Flying!!