GUY NORRIS / LOS ANGELES
Rejected/minimum speed take-off study reveals encouraging field length performance
Recently completed rejected take-off, minimum speed take-off and landing tests on the Boeing 777-300ER have revealed "significantly better" than expected field length performance, leading Boeing to offer increases in predicted range and payload.
Brake tests, combined with the tail strike protection system, show a field length improvement of around 305m (1,000ft) at sea level at 30°C (86°F). Converted into mission improvements, Boeing says this translates to a 4,800kg (10,570lb) payload increase from Manchester in the UK to Singapore, and 3,100kg or 30 more passengers at 42°C on a Dubai to New York flight. The boost comes on top of a 1% fuel mileage improvement over pre-flight estimates that was discovered during earlier tests. Boeing translates this into either a 140km (75nm) design range increase or a 1,100kg payload increase on long routes such as Los Angeles to Taipei.
The field length tests were conducted at Roswell, New Mexico, and Edwards AFB, California, at take-off weights of around 351,900kg and, in the case of the rejected take-offs, involved 100% worn brakes from Goodrich and Messier Bugatti. Although this is higher than the 344,850kg certification weight, it continues to be used for maximum test weights to provide consistency with earlier phases of the test programme (Flight International, 3-9 June), as well as proving margin for potential variants downstream.
The flight tests are about half-way through the planned 1,500h - 100h less than originally predicted when they began in February.
Source: Flight International
