On 21 March 2004, an MD-83 operated by Luxor Air, performed an unstabilised non-precision approach (NPA) to runway 21 at Nantes Atlantique airport, at night and under Instrument Meteorological Conditions (IMC) conditions, which resulted in near-Controlled Flight Into Terrain (CFIT) and a go around contrary to the standard missed approach procedure.
This is an extract from the official report of the incident published by the Bureau d'Enquêtes et d'Analyses (BEA) pour la Securite de l’Aviation Civile, France:
“…the crew was cleared to descend towards 3,000 ft, and was then cleared for approach…The airplane was then on a 330° heading on autopilot in NAV mode (GPS navigation). The co-pilot selected VOR/LOC mode to intercept the 043° radial inbound on the NTS VOR. The airplane was configured for landing and the Captain told ATC…that he planned to descend from three thousand feet to five hundred feet then..[1 minute later]that the airplane was established on the approach radial.
Note that the MDA is 500 feet but the approach includes a series of step-down fixes, see the approach plate below:
LFRS Approach plate. Reproduced from the Official Report.
The crew then noticed, on the navigation instruments, that there was a variation of about 0.8 NM between the airplane’s route and the localizer radial. The VOR CAP indicator was displayed on the FMA. The co-pilot changed the autopilot to HDG SEL to intercept the radial with a selected heading of about 250°.
8 NM DME away, a short time before the airplane crossed the radial, the Captain asked the co-pilot to continue on that heading in order to go around a stormy area that he thought he had identified on the weather radar…The airplane made its descent at an average rate of descent of a little less than 1,000 ft/min. The crew reported suffering significant turbulence during this phase.
…the controller intervened to say that the airplane seemed to him to be too low. The Captain asked the co-pilot to select ALT HOLD and told the controller that he was maintaining five hundred feet. In addition, the co-pilot decided to go back towards the radial with an 80° left turn via the HDG SELECT mode. Coming out of the turn, the airplane probably broke through the cloud layer and a [ground] witness then noticed that it was starting a go-around…the Captain announced the go-around to the controller.
[at 6 DME the aircraft should have been at a minimum altitude of 1730 feet]
The airplane climbed towards three thousand feet. As it was passing through the radial on a 170° heading, the controller informed the crew that they could start descending again. The Captain answered that he preferred to perform the [standard] approach again. The controller vectored them and gave them the altitude cues during the descent.
Radar data and radio communications - click on the image to enlarge.
Reproduced from the Official Report.
The second approach and the landing were uneventful.
The Cause of the serious incident was given as:
The direct cause of the incident was a combination of different factors that led the crew to abandon standard operating procedures:
- the incorrect interpretation of meteorological data from the weather radar;
- lack of knowledge of protected areas and, more generally, lack of skill in VOR DME procedures;
- improvising an action (deviation from the procedure) without any defined or shared plan of action.
The following is stated as contributory factors to the serious incident:
- lack of training in Crew Resource Management by the operator;
- the weakness of the operator’s feedback structure;
- discomfort and stress due to meteorological conditions;
- the crew's perception of the meteorological conditions, which both led to an erroneous interpretation of the weather radar data and, further, led them to fail to take into account the effects of the wind on the descent profile;
- the difficulty in checking and cross-checking from the time the crew deviated from the final approach path;
- a deviation within the air traffic control organisation between the established procedures and practice, which led to some non-published approach paths;
- lack of synergy between the controller and the crew;
- a probable hypo vigilance phenomenon on the part of the controller, who was alone at his work station at the time.
The Report's recommendations, beginning on page 49, also focus on institutional and organisational issues including the airline operator and the air traffic control service provider (see Further Reading).
For further information see the full serious incident report published by BEA.