AAIB reports on Ryanair Boeing 737 level bust near London Stansted

According to the AAIB’s synopsis, after a manually flown go-around and missed approach procedure (MAP), the first officer handed over controls to the captain to allow for setting up of the Flight Management Computer (FMC).

“The aircraft subsequently started a descent which was not noticed by either member of the crew. The aircraft descended about 550 feet before this was noticed and action taken to correct it. ”

According to AAIB, since the 737 MAX 8-200 was more than 200 ft below its cleared altitude, it was classified as a ‘level bust.’ However, while this did not meet criteria defined by International Civil Aviation Organization (ICAO) for accidents or serious incidents, an investigation was initiated to highlight Ryanair’s reaction.

The Ireland-based low-cost carrier amended its handover procedure in its Flight Crew Operations Manual (FCOM). The aircraft involved has continued flying since March 2024.

During post-incident interviews, it emerged that local air traffic control (ATC) did not pressure flight crew despite their quick decision for go-around.

“He added that they should have asked for more time to ensure GA and MAP had been fully completed which would probably have ensured A/P and A/T were engaged as they should have been by PF at time. ”

While captain knew handover procedure within Ryanair’s FCOM; first officer said, “this was first time he had handed over control during manual flight and he did not know precise call-outs stated in FCOM.”

“Whilst he did not highlight fact that he was manually flying; he assumed commander realized this.”

Ryanair’s FCOM requires PF clearly state status Autopilot Flight Director System (AFDS) & A/T before handing over controls:

“Example manual flight; You have control autopilot & autothrottle disengaged LNAV VNAV descending FL100”. Example autopilot & autothrottle engaged; You have control CommandA N1 LNAV VNAV maintaining FL370.”

During ‘level bust,’ another helicopter cleared land London-Stansted with no “separation minima applicable between aircraft” estimated two aircraft separated vertically by .7 nautical miles horizontally .3 kilometers vertically .00 ft.

“Having leveled off after GA aircraft descended00 ft from cleared altitude result incorrect procedure used during handover control commander monitoring co-pilot actions rather than aircraft.”

Following incident Ryanair amended FCOM expanding ‘Handover Control’ guidance PM response affirm transfer controls manual automatic flight.