Boeing's efforts to secure 330min extended operations (ETOPS) certification for the 787 have been further delayed owing to a new regulatory issue.
The 330min threshold was scheduled to be cleared on the first 787 to enter service in October 2011.
Both the Rolls-Royce Trent 1000 and General Electric GEnx-1B engines for the type have been approved for 330min ETOPS. But Boeing introduced the 787 with only 180min ETOPS certification, and pushed back 330min to early 2012. The delay prevented United Airlines from launching an inaugural flight from Houston to New Zealand.
Boeing blamed the delay on additional software work to comply with a new regulation to alert the crew of low fuel, especially in the event a fuel leak.
The US Federal Aviation Administration imposed the regulation after an ETOPS incident in 2001, when the pilots of an Air Transat Airbus A330, unaware of a fuel leak, were forced to glide to an emergency landing in the Azores.
The 787 flightdeck includes a low-fuel alert for the crew, says Mike Sinnett, the Boeing chief project engineer. "The airplane meets all the requirements," he says.
But the FAA and Boeing have still not resolved a new regulatory issue that has arisen because the aircraft has logged several months of service experience, Sinnett says. The FAA requires airframers to report all issues that could impact ETOPS safety.
It appears uncertain whether the FAA can approve 330min ETOPS while Boeing has unresolved reports from in-service experience.
Sinnett says Boeing "never thought through" the problem of how to clear ETOPS certification with an in-service aircraft. "It's an open procedural question," he says. "How do we account for in-service experience?"
Boeing says the 787's in-service experience has been similar to the history of benchmark programmes like the 777, which achieved a 97.9% dispatch reliability rate in the first year of service.
But the type has experienced a string of high-profile technical problems over the last six weeks, including electrical malfunctions that grounded several aircraft briefly and, more recently, a battery explosion that caused severe damage in a small compartment of a Japan Airlines 787.