Investigators have detailed the chaotic crew response to a Western Air Saab 340A's electrical failure, which eventually led to an unstable approach and gear collapse at Freeport's Grand Bahama airport.
The aircraft had departed Grand Bahama for Nassau on 7 February last year, but experienced a serious electrical bus failure just 2min after take-off.
Confusion followed in the cockpit over the nature of the failure – which affected multiple systems – and the correct course of action.
One pilot wanted to continue to Nassau, says the Air Accident Investigation Department of the Bahamas, while the other wanted to return to Freeport.
All of the captain's flight instruments had been lost, as a result of the failure, but he still chose to take control of the Saab from the first officer – who was the designated flying pilot and still had instrument access. The captain even requested that the first officer should "feed him" flight data from his functional instruments.
The first officer's workload increased "greatly" as he provided the captain with aircraft and engine parameters, as well as data on airport location and distance, while also trying to find the quick-reference handbook.
"No evidence was overheard on the [cockpit-voice recording] of either pilot locating or identifying the correct checklist to effectively deal with the initial abnormal situation they encountered," says the inquiry.
The pre-landing checklist was also called for, it adds, but was not captured on the recording as being completed.
Investigators have attributed the checklist failures to "ineffective crew resource management".
As the aircraft returned to Freeport the crew realised that they were experiencing problems with landing-gear indications, and were unsure of the position of the undercarriage after deployment.
The crew was given permission to overfly the airport and air traffic control advised that the landing-gear was apparently down.
While the cabin crew was told that the aircraft was returning to Freeport, the inquiry says: "No urgency or instructions on preparation for a possible gear-up landing was [found on the recording]."
The recording did, however, capture extraneous conversation including the crew's discussing whether they should photograph the instruments to avoid being blamed by management.
"This back-and-forth non-essential dialogue during a critical phase of flight, with system failures occurring without appropriate crew corrective input, continued for quite some time," the inquiry says.
After an initial missed approach – because the captain, with no instruments, was flying too high and fast – the aircraft conducted a second landing attempt, also flown faster than normal because the captain believed the landing flaps were unavailable.
"Confusion continued up until seconds before the aircraft touched down as evidenced from the [cockpit] recording," says the inquiry.
Just after touchdown, almost halfway along the near-11,000ft runway, the left-hand main landing-gear collapsed. The left-hand propeller and wing contacted the ground and the aircraft slid for a further 1,600ft, veering off the left side of the runway 06 and coming to rest 200ft from its edge.
Only minor injuries were sustained among the 34 occupants during the excursion and evacuation. The aircraft (C6-HBW) suffered substantial damage.
"The apparent rush to get on the ground without exploring other possible options to identify and verify landing gear security also contributed to the severity of this accident," says the inquiry.
It states that the pilots did not give a reason as to why they did not consider quick-reference handbook instructions for abnormal landing-gear indications or emergency extension.
Inadequate system knowledge, and a lack of situational awareness, allowed the initial failure to escalate into "additional compound dependent failures", and subsequently into an emergency, the investigators conclude.
Inspection of the aircraft also determined that neither the 30min cockpit-voice nor the flight-data recorder, both relying on magnetic-strip technology, complied with ICAO requirements.
Source: Cirium Dashboard