Pilots of a LOT Boeing 767-300ER involved in a gear-up landing had relied on the alternate gear-extension system functioning, after a hydraulic leak, and had not prepared for the situation to deteriorate in the final moments of approach.

Investigators indicate the crew was caught by surprise when the alternate extension system malfunctioned just before arrival in Warsaw, and ran out of time to analyse the problem – a situation exacerbated by difficulties in reaching specialist personnel on the ground.

The hydraulic leak, which prevented operation of the conventional landing-gear deployment system, occurred about 15min after flight LO16 departed Newark on 1 November 2011.

Polish investigation authority PKBWL says the crew contacted LOT's operations centre which advised continuing the transatlantic flight.

After reviewing the information from the crew, it adds, the airline's maintenance co-ordination centre "did not consider" that specialist support for the crew was necessary.

"No further analysis was undertaken and no further action was considered related to probability of escalation of the abnormal situation on board," says the inquiry.

The crew, as a result, conducted the flight on the basis that they would use the alternate gear-extension system on approach to Warsaw.

PKBWL indicates that the pilots took advantage of the transatlantic crossing time to prepare for the landing, including discussing the first officer's previous experience of using the alternate extension system during a flight three years earlier.

But these expectations for the landing procedure were completely disrupted when, during approach, the crew's attempts to lower the landing-gear twice failed, and the aircraft was forced to execute a go-around.

Not until the failure of the alternate-extension system did the crew seek further advice and consultation. At this point the aircraft had 7.7t of fuel remaining.

"Only then did the process of searching for the right people commence," the inquiry points out.

While a 767 instructor pilot became available within a short time, technical and access problems with radio stations meant a 767 ground engineer had to drive to the operations centre, delaying contact with the flight for 20min.

The operations centre did not have a risk-assessment system and had not anticipated escalation of the crisis, contributing to the shortening of time available to analyse the situation. Investigators state that the centre did not breach rules but the radio station problems amounted to a "serious" issue of neglect.

"Time deficit meant the ground engineer was not able to fully analyse diagrams of the alternate landing-gear extension system," says the inquiry.

Investigators traced the extension-system failure to a circuit-breaker which had been tripped, but which went undetected during the flight and during the subsequent attempts by the crew, after the aborted approach, to determine why the failure had occurred.

The inquiry says the first officer cycled, and rechecked, several circuit-breakers as the aircraft flew a holding pattern at Warsaw, but not the breaker responsible for the problem. The captain could not assist with the check because he was concentrating on flying the aircraft.

Pilots of two Polish fighters accompanying the 767 informed that the landing-gear was still retracted and the 767 crew attempted to use gravity-extension, but this effort was unsuccessful.

Fuel concerns led the crew to abandon the attempt and, 80min after the go-around, the aircraft carried out a gear-up landing on runway 33. It touched down with 1.6t of fuel remaining.

Source: Cirium Dashboard