Commercial pilots who remove themselves from duty worry their actions leave a negative impression with management and don’t feel comfortable doing so, newly released research has revealed.

According to a study conducted in the second half of 2016 by the Australian Transport Safety Bureau (ATSB), over 90 per cent of pilots indicated their employer offered a formal process for removing themselves from duty due to fatigue.

About one third of respondents indicated they removed themselves from duty at least once in the past year, mostly between one and three days.

The study found that pilots who removed themselves from duty generally perceived their actions left a negative impression with management (with the exception of aeromedical pilots), and did not feel comfortable doing so.

The majority of survey respondents reported they were sufficiently well rested by the end of their last duty.

Over half of pilots reported having seven hours of sleep or more in the previous 24 hours, and over 60 per cent reported having more than 14 hours in the previous 48 hours, at the end of the last flight.

The survey also found a small but significant number of pilots (10 per cent and 17 per cent) who reported obtaining less than five hours of sleep in the previous 24 hours, or less than 12 hours in the previous 48 hours, respectively, at the end of their last flight.

The ATSB noted these sleep thresholds have been shown to be associated with impaired performance.

Less sleep on duty was more prevalent for international and domestic jet airline pilots than other air transport pilots (regional, charter and aeromedical).

While around one third of the respondents reported obtaining the same amount of sleep at home as they did while on duty, around half of international and domestic pilots reported obtaining less hours of sleep on duty than at home.

About 15 per cent of international pilots responded they had no rest during their last international flight.

The research indicated that some domestic pilots have negative perceptions of rest opportunities provided by their employers.

According to the study, domestic pilots completed duties on a stand-by day more often than other pilots.

Furthermore, domestic pilots believed the rest period between duties was too short, duty periods were too long, and access to food during duties was more difficult compared with other pilots.