What happened
On 23 March 2006, a B737-80 and registration EI-DHX was operating a scheduled passenger flight from London Gatwick to Ireland West Airport, Knock. During the approach phase, the flight crew encountered significant confusion regarding the active runway. While the crew had planned for an NDB approach to runway 09, Air Traffic Control (ATC) informed them that the necessary facilities were unavailable due to ongoing airport works, suggesting an ILS approach to runway 27 instead.
As the aircraft descended, the crew became preoccupied with reprogramming the Flight Management Computer (FMC) with a new waypoint. This distraction led to a high-speed, non-configured approach to runway 27. The aircraft descended to approximately 410 feet above ground level with a groundspeed of 265 knots, triggering an Enhanced Ground Proximity Warning System (EGPWS) "too low terrain" alert. The crew subsequently performed a non-procedural go-around. Following a period of holding, the aircraft successfully completed a circling approach and landed safely on runway 09.
The investigation
The AAIU investigation established that the crew was operating an aircraft with relatively low experience on the B737-800 compared to the older 737-200 models. The investigation revealed that critical aeronautical information regarding the unserviceability of the CON DVOR/DME was not available to the pilots during flight planning. Furthermore, the investigation found that the Jeppesen Airways Manual had not been updated with the relevant Chart NOTAMs at the time of the incident.
Flight data monitoring (OFDM) confirmed that the approach was characterized by high energy, including excessive speed and a failure to deploy flaps or landing gear. The investigation also noted that the descent profile deviated from the operator's standard operating procedures (SOPs).
Findings
- The primary cause of the incident was the crew's preoccupation with manual FMC programming, which diverted attention from critical flight monitoring tasks.
- The crew's lack of familiarity with the advanced automation of the B73 37-800 contributed to a loss of situational awareness.
- A systemic failure occurred as the operator failed to provide the crew with the latest AIP Supplement regarding unavailable navigational aids.
- A secondary systemic failure was identified in the Jeppesen Company's process, as necessary Chart NOTAMs were not issued in a timely manner.
- The incident was classified as a situation where controlled flight into terrain (CFIT) was only marginally avoided.
Safety action
Following the investigation, several safety recommendations were made to the operator regarding the preservation of flight data, the necessity of comprehensive approach briefings, and the requirement to re-brief when approach types change. Additionally, recommendations were directed at the Jeppesen Company to improve the processing of AIP Supplements and at the Irish Aviation Authority to facilitate flight data monitoring forums.