Created Tuesday, Nov 23rd 2021 17:54Z, last updated Tuesday, Nov 23rd 2021 18:00Z
A Royal Air Maroc Boeing 737-800, registration CN-ROJ performing flight AT-780 from Rabat (Morocco) to Paris Orly (France), was on an Cat III ILS approach to Paris Orly when the crew decided to go around from about 1400 feet due to a technical fault and to divert to Lyon (France). The aircraft climbed to FL250 and was on an ILS approach to Lyon's runway 35R when the aircraft went through the localizer without intercepting the localizer. The crew opted to perform a manual approach to runway 35R but descended resulting in Minimum Safe Altitude Warnings at the ATC desk and EGPWS alerts in the cockpit. The crew climbed to 5000 feet, was vectored for another approach to runway 35R and landed without further incident.

France's BEA rated the occurrence a serious incident, labelling the type of occurrence as "unstabilized approach, descent below minimum safe altitude, MSAW and EGPWS alerts" and as controlled flight into terrain, and opened an investigation.

On Nov 23rd 2021 the BEA released their final report in French only concluding the probable causes of the serious incident were:

- Two concurrent independent failures of two different aircraft systems, the origin and consequences of which were difficult to establish for the crew without adequate information in the operational documentation and insufficiently salient alarms triggered by the aircraft systems

- Gradual loss of confidence into the aircraft systems by the crew during the course of the flight causing significant stress onto the crew who focussed their attention on the remaining fuel levels

- The degradation of CRM in times of high workload, that became particularly high due to the need of managing an IRS FAULT during the go around

- The operating logic of the Flight Control Computer (FCC), which in accordance with its specifications does not provide monitoring inertial data of the ADIRUs except when both autopilots are engaged during approaches.

- The logic of internal ADIRU monitoring with respect to verifying validity of data transmitted to other systems. The criteria for drift angle failure, which caused the IRS FAULT alarm, can appear late in relation to the beginning of the ADIRU Inertial Reference System malfunction

- Unsystematic reporting of technical malfunctions by crews like the disappearance of F/D, ADIRU malfunctions and automatic disconnections of the autopilot

- The persistence of intermittent failures

As the BEA have pledged to release all reports in English in due time, The Aviation Herald will summarize the final report in more details as soon as the English version has been released.

Metars Lyon:
LFLL 301230Z VRB03KT 4000 BR BKN007 01/M00 Q1037 NOSIG
LFLL 301200Z VRB02KT 4000 BR OVC006 01/M01 Q1037 NOSIG
LFLL 301130Z 36004KT 4000 BR OVC006 00/M01 Q1037 NOSIG
LFLL 301100Z VRB02KT 4000 BR OVC005 00/M01 Q1038 NOSIG
LFLL 301030Z VRB02KT 3000 BR OVC004 M00/M01 Q1038 NOSIG
LFLL 301000Z 00000KT 3000 BR OVC004 M00/M01 Q1038 NOSIG
LFLL 300930Z 36002KT 2000 BR OVC003 M01/M01 Q1038 NOSIG
LFLL 300900Z VRB02KT 3000 BR OVC002 M01/M01 Q1038 NOSIG
LFLL 300830Z VRB03KT 2500 0800S R35L/P2000 R17R/P2000 R35R/P2000 R17L/P2000 BCFG OVC002 M01/M01 Q1038 NOSIG
LFLL 300800Z VRB02KT 2500 0800S R35L/1700U R17R/P2000 R35R/1700U R17L/P2000 BCFG OVC001 M01/M02 Q1038 NOSIG

Metars Paris Orly:
LFPO 301200Z VRB02KT 0300 R02/0800N R26/0500N R08/0550N R24/0400N R06/1100D FZFG VV/// M02/M02 Q1038 TEMPO 0100 FZFG VV///
LFPO 301130Z VRB03KT 0300 R02/0550U R26/0325N R08/0900U R24/0500N R06/0600U FZFG VV/// M02/M03 Q1038 TEMPO 0100 FZFG VV///
LFPO 301100Z VRB02KT 0250 R02/0400N R26/0325N R08/0650D R24/0700N R06/0400N FZFG VV/// M02/M03 Q1038 TEMPO 0100 FZFG VV///
LFPO 301030Z VRB03KT 0250 R02/0500U R26/0300N R08/0700U R24/0650U R06/0450N FZFG VV/// M02/M03 Q1038 TEMPO 0100 FZFG VV///
LFPO 301000Z VRB02KT 0200 R02/0350N R26/0300N R08/0400N R24/0400N R06/0400N FZFG VV/// M02/M03 Q1038 TEMPO 0100 FZFG VV///
LFPO 300930Z VRB02KT 0200 R02/0350N R26/0250N R08/0600U R24/0325N R06/0400N FZFG VV/// M02/M03 Q1038 TEMPO 0100 FZFG VV///
LFPO 300900Z VRB02KT 0150 R02/0300N R26/0225N R08/0375N R24/0350N R06/0400N FZFG VV/// M02/M03 Q1038 TEMPO 0100 FZFG VV///
LFPO 300830Z VRB01KT 0200 R02/0375N R26/0225N R08/0325N R24/0350N R06/0400N FZFG VV/// M02/M02 Q1038 TEMPO 0100 FZFG VV///
LFPO 300800Z VRB01KT 0250 R02/0350N R26/0275N R08/0400N R24/0400N R06/0450N FZFG VV/// M02/M02 Q1038 TEMPO 0100 FZFG VV///

Track Related Flights on Airportia: AT780, Twitter: #AT780
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