sheppey
13th Mar 2014, 05:57
Interesting ATSB report on an A320 flight below min safe altitude for procedure into Queenstown. See link.
Investigation: AO-2012-103 - Descent below segment minimum safe altitudes involving Airbus A320-232, VH-VQA near Queenstown, New Zealand on 16 July 2012 (http://www.atsb.gov.au/publications/investigation_reports/2012/aair/ao-2012-103.aspx).
One sentence in the report raised the eyebrows and maybe an Airbus pilot could clarify the procedure.
The report stated the aircraft got within 1097 feet from terrain due to the (mismanaged) descent profile on autopilot. It didn't say if the aircraft was IMC or VMC. If IMC, it could lead to a close shave due terrain. According to the ATSB report, on realising the aircraft was below minimum safe altitude for correct profile, the captain "commenced climb using auto-flight vertical speed mode". He then regained the correct safe altitude.
Getting that close to terrain in IMC for example, would it not have been quicker to immediately disconnect the autopilot and autothrottle and manually pitch up to the desired pitch attitude similar to a go-around - rather than remain on automatics and select an appropriate rate of climb on the auto-flight vertical speed mode with its inherent delay as the aircraft changes from a descent through level flight and into whatever climb rate was selected?
What selected rate of climb would the average pilot select in order to rectify the situation described in the report? If the aircraft is in VMC then the climb to the correct safe altitude is not so urgent on autopilot -but in IMC well that's a different story.
In other words, is it safer under the circumstances described in the ATSB report to get back to the correct safe altitude asap - which means manually such as would happen given a GPWS pull-up - or more leisurely by staying on autopilot and gradually return to safe height? Research papers on automation dependency have frequently referred to the reluctance by pilots to disengage the automatics even if circumstances dictated it was appropriate at the time.
Investigation: AO-2012-103 - Descent below segment minimum safe altitudes involving Airbus A320-232, VH-VQA near Queenstown, New Zealand on 16 July 2012 (http://www.atsb.gov.au/publications/investigation_reports/2012/aair/ao-2012-103.aspx).
One sentence in the report raised the eyebrows and maybe an Airbus pilot could clarify the procedure.
The report stated the aircraft got within 1097 feet from terrain due to the (mismanaged) descent profile on autopilot. It didn't say if the aircraft was IMC or VMC. If IMC, it could lead to a close shave due terrain. According to the ATSB report, on realising the aircraft was below minimum safe altitude for correct profile, the captain "commenced climb using auto-flight vertical speed mode". He then regained the correct safe altitude.
Getting that close to terrain in IMC for example, would it not have been quicker to immediately disconnect the autopilot and autothrottle and manually pitch up to the desired pitch attitude similar to a go-around - rather than remain on automatics and select an appropriate rate of climb on the auto-flight vertical speed mode with its inherent delay as the aircraft changes from a descent through level flight and into whatever climb rate was selected?
What selected rate of climb would the average pilot select in order to rectify the situation described in the report? If the aircraft is in VMC then the climb to the correct safe altitude is not so urgent on autopilot -but in IMC well that's a different story.
In other words, is it safer under the circumstances described in the ATSB report to get back to the correct safe altitude asap - which means manually such as would happen given a GPWS pull-up - or more leisurely by staying on autopilot and gradually return to safe height? Research papers on automation dependency have frequently referred to the reluctance by pilots to disengage the automatics even if circumstances dictated it was appropriate at the time.