The Aviation Safety Council (ASC) of Taiwan has issued their investigation report into the loss of TransAsia Airways (TNA) ATR 72-500 B-22810 on 23 July 2014 during an attempted landing in poor weather.  It highlights a number of important safety lessons.

The Accident

During a non-precision approach, after around 34 minutes of holding, the aircraft impacted terrain in a residential area 800m NE  of the threshold of runway 20 at Magong Airport, Penghu Islands, Taiwan during a heavy thunderstorm associated with Typhoon Matmo. Ten of the 58 on board survived.

The Commander was Pilot Flying  (age 60, ex-military, joined airline in 1992, ATPL, 22,994 hours total, 19,070 hours on ATR42/72) and the First Officer (FO) was Pilot Monitoring (age 39, direct recruit by the airline in 2011, CPL, 2,393 hours total, 2,084 hours on ATR42/72).
There was no approach briefing before commencing descent and the FO “proposed that he conducted the before landing check by himself without a cross-check”, which the Commander approved.

The ASC say the Controlled Flight Into Terrain (CFIT) occurred because:

The crew continued the approach below the [330ft] minimum descent altitude (MDA) when they were not visual with the runway environment contrary to standard operating procedures.

GE222's altitude and track deviations (due to the PF's left control inputs and crosswind) while attempting to visually locate the runway (Credit: ASC)GE222′s altitude and track deviations (due to the PF’s left control inputs and crosswind) while attempting to visually locate the runway (Credit: ASC)

When the aircraft had descended to 249 feet, the first officer illustrated the position of the [Missed Approach Point] MAPt by saying “we will get to zero point two miles”. At 1905:44, altitude 219 feet, the captain disengaged the autopilot. Four seconds later, the captain announced “maintain two hundred”. The captain maintained the aircraft’s altitude between approximately 168 and 192 feet in the following 10 seconds… The flight crew intentionally operated the aircraft below the MDA…while attempting to visually sight the runway so they could land the aircraft.

Neither flight crew member recognised the need for a missed approach until the aircraft was at just 72ft, 0.5 nm beyond the MAPt, where impact with the terrain was “unavoidable”.

GE222 accident site (Credit: ASC)
GE222  impact and accident site (Credit: ASC)

Further accident site photos can be found here and here.

Having discussed the effect of a cockpit gradient, the ASC note that in interviews with other TransAsia crews the consensus was that “the occurrence first officer would accommodate the captains’ flying habits, and tended not to challenge captains’ landing decisions”.  We have previously discussed whether it is better for the Commander to be the Pilot Flying or the Pilot Monitoring and this accident re-emphasises that question.  However, we do note below that the FO did intervene after several course, mode and communication errors by the Commander.

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