French investigators have determined that substantial damage to an Airbus A330-200, following a hard landing at Caracas, went undetected until pilots operating the return service found they could not retract the gear.
The Air France aircraft had been conducting an instrument approach to Caracas’ runway 10 in turbulent conditions. Upon intercepting the glideslope at 6nm the crew disconnected the autopilot and autothrust.
With the absence of the autopilot the captain faced a “heavy workload” given the changing direction and strength of the wind, says French investigation authority BEA.
Although the captain was correcting deviations from the glidepath, BEA says the approach was “not stabilised” below 500ft. Just before touchdown a combination of reduced thrust, pitch-down commands and varying winds caused the jet to descend quickly, generating a sink-rate warning at 35ft.
It landed with a descent rate of 1,200ft/min and an impact of 2.74g, and the captain recorded the hard landing in the technical log.
But a technician looking into the situation found no evidence that the aircraft’s systems – upon detecting the criteria for a hard landing – had transmitted any automated maintenance report corresponding to the date of the flight, 13 April 2011.
He checked with the airline’s maintenance centre in Paris but it had not received any such report, and the technician concluded that there was no further action required.
Routine inspections of the aircraft (F-GZCB) did not detect any problem with the A330 and it was cleared for the return flight to Paris. But during the initial climb the crew was unable to retract the landing-gear and received several alerts relating to the cabin air conditioning.
The aircraft returned to Caracas, having burned off excess fuel, and landed at near maximum weight.
BEA believes the take-off roll from Caracas or the landing exacerbated unseen internal damage to the landing-gear caused during the initial hard touchdown. As a result the A330 sustained further damage, notably to its right-hand main gear, which was only clearly observed after it parked.
The inquiry notes that a phenomenon termed 'lock-up' can sometimes affect generation of an automated maintenance report by the aircraft's data-management unit.
Investigators subsequently recommended that maintenance procedures should be changed to take into account the possibility of such a report being absent in the event of a hard landing.