Human error by a Pilot

On 08.08.2014, an Indian commercial passenger jet was involved in loss of altitude incident during cruise over Turkish Airspace. The incident occurred after the aircraft had flown for 04 hours 43 minutes from Mumbai. The aircraft was flying on westerly track which was between 230 and 300 degrees and was flying on auto pilot at a height of 32000 feet. The Pilot in command was undergoing controlled rest as per statutory requirements and the controls were with the First Officer.

The First Officer, while updating the direction heading 292 degree, instead turned the altitude knob to 292 FL (29000 feet) and pressed thereby causing the aircraft to descend as the auto pilot obeyed the order to descend to 29000 feet. The Turkish Air Traffic Controller noticed the aircraft descent and called through radio about the unauthorized descent. Subsequently, the First Officer pressed ALT HOLD and climbed back to FL320 (32000 feet). The First Officer then woke up the Captain who was undergoing controlled rest and informed him of the incident. (Source: DGCA incident report).

In our industry, there have been numerous incidents where wrong setpoints or outputs have been entered by the DCS operator, leading to plant upsets. Do you consider this in HAZOP's?

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