Expectation Bias

Oct. 26, 2012
Hearing what we expect to hear may not be what was said.

A recent pilot safety tip published by the FAA Safety Team talks about expectation bias; the suggestion that we sometimes hear what we expect to hear. The example used in the safety tip to explain the concept of expectation bias went like this:    

A pilot calls the control tower and reports ready for departure on Runway 10.  The controller clears the pilot for takeoff on Runway 17. The pilot reads back his clearance for takeoff on Runway 10 – and then stops on the runway when he spots an aircraft inbound in an opposite direction for his or her runway. In this case the pilot was captured by the expectation of what he or she was expecting to hear. The European Air Traffic Control (ATC) unit Eurocontrol defines ATC expectation bias as “Having a strong belief or mindset toward a particular outcome.” Hearing what we expect to hear is frequently listed as a causal factor for pilot deviations that occur both on the ground and in the air

After reading this safety tip I speculated on how this same situation would apply to aircraft maintenance, especially in the rapid-paced noisy environment of airport line maintenance and ramp operations. How could an expectation bias catch the aircraft maintenance professional in a situation where he or she expected to hear a certain response, direction, or instruction but what was said was not the case. One possible scenario that comes to mind would be a technician who was asked by a coworker, let’s say an inspector or supervisor, a simple question over a two-way communication device like, “We are ready to go, did you close that access panel?” The expected response or perhaps the hoped response from the coworker may be something like “Yes I did it’s all closed up.” But what if the response was not the one expected and even masked by a partially garbled transmission or a noisy environment? What if the response was something like, “Yes…(garbled sounds) I’ll … (more garbled sounds) … soon.” Could the response have been, “Yes I’ll do it soon,” and not the expected response the task had been completed, the aircraft ready to be returned to service, and the technician will be back in the ready-room soon?

Rapid communication is part of our daily lives and workplace distractions and multi-tasking in a maintenance environment can compound the already difficult challenges of effective communications. Similar to the pilot communication with ATC, when issued instructions or asked questions, listen intently and repeat them to yourself and back to your coworker.

Ask yourself, did this quick verbal instruction make sense; did I hear this correctly? Much has been written and taught on effective communications. Attend any training session relating to working with others, supervising and managing people, and listening and understanding is generally on the top of the list of important factors. If in doubt ask for clarification and use the popular pilot communication phrase, “Say again please.”