Pilots fixated on reprogramming flight management computer during descent
A Ryanair Boeing 737-800 on approach to Knock airport, Ireland, "only marginally avoided" controlled flight into terrain, according to the Irish Air Accident Investigation Unit (AAIU) report on the 23 March incident. The AAIU says the principal cause was that both pilots fixated on reprogramming the flight management computer (FMC) while the aircraft continued its descent.
A contributory cause was a "systemic failure" at the airline and at chart supplier Jeppesen, which meant the pilots did not have up-to-date information about the navigational aids at Knock.
The two pilots were experienced 737-200 operators, but both had less than 400h on the -800. Before departure from London Gatwick they had programmed the FMC for a non-directional beacon (NDB) approach to runway 09 at Knock because they knew there was a strong easterly wind. But they did not know, because Ryanair's pre-flight briefing computer system data was incomplete, that such an approach was not available because of work on the navigation beacons at this non-radar airport.
When the crew called Knock, they were told they would have to carry out an instrument landing system approach to reciprocal runway 27 from which they could join the visual circuit to land on 09, although the cloudbase - broken at 900ft (275m) above ground level (AGL) - was marginal.
What transpired, says the AAIU, was an unbriefed descent in which Shannon radar assisted the crew to intercept the ILS. But as the pilots fixated on reprogramming the FMC for the new approach, they arrived over the airport at 410ft AGL with gear and flaps up and an airspeed of 265kt (490km/h).
They saw the runway, heard the enhanced ground proximity warning system "too-low terrain" alert, and carried out a non-standard missed approach to join the "OK" NDB hold while they decided what to do. Knock ATC cleared them to hold at OK at 4,000ft from where, after 25min considering their options, they carried out a successful NDB/ILS 27 descent followed by a visual circuit to land on 09.
The AAIU says it did not have data from the cockpit voice recorder or flight data recorder because it had been overwritten, so they used information from the airline's operational flight data monitoring system. Ryanair did not report the event until 4 April, which the AAIU says is "unacceptable" and contrary to regulations.
Other probes |
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| Ryanair is under investigation by the Italian air accident investigation agency ANSV for a 7 September 2005 attempted bad-weather approach into Rome Fiumicino. During an unstabilised approach to runway 34R, the non-flying co-pilot had to intervene to initiate a late go-around, then the crew elected to divert to Pescara. Another Ryanair crew carried out an "irrational and inexplicable" steep approach at Stockholm Skavsta airport on 21 July 2005, says the AAIU. |
Source: Flight International
