Guy Norris/LOS ANGELES

UNITED AIRLINES has unleashed a fierce attack on the reliability of its newly acquired Boeing 777s.

A letter from a senior United executive to Boeing, dated 13 February, called the aircraft's reliability and performance a "major disappointment".

Within 24h of the letter from United fleet operations executive vice-president Joseph O'Gorman, to Boeing 777 general manager Ron Ostrowski, appearing in a Wall Street Journal article on 6 March, United tried to limit the damage saying, that the 777 "...is outperforming all other new aircraft, we have introduced into our fleet".

In the letter, O'Gorman says that 777 reliability and performance "...has been a major disappointment". He adds that "...the number of pilot write-ups and flight cancellations, as well as the aircraft out-of-service time, has been intolerable". By 6 March, O'Gorman was quoted as saying: "The 777 is an excellent aircraft, we just want to make it better."

Boeing says that the problems addressed in the letter, ranging from electrical malfunctions and "freezing" cables, "...were being worked on before the letter came out". The company adds that no "surprise" issues were raised in the letter, and that an aircraft-on-ground team "...has been working on the issues". It adds that a despatch reliability rate of 97.5% had been achieved through to the end of December for the 777. "No other new aircraft has come close to that," Boeing claims.

By comparison, the rival Airbus A340's entry into service started off trouble-free in March 1993, but by January 1994 its operational reliability had slumped to 94% because of a series of technical problems, from which it has since recovered.

United was the launch customer for the 777, introducing the aircraft into service on the Chicago/London route in June. The airline has possession of ten of the 24 aircraft it has on order.

Source: Flight International