GUY NORRIS / SEATTLE
Longer range model set to be unveiled at the Dubai air show has greater MTOW than first production batch
Boeing plans to offer a higher-gross-weight, longer-range variant of the 777-300ER from late 2004, based on additional margins discovered during the latter stages of the flight-test programme.
The latest variant, details of which are being revealed this week at the Dubai air show, will have a maximum take-off weight (MTOW) of 351,850kg (775,000lb) and a fuel volume-limited range of 14,250km (7,705nm). This gives it almost the same range asthe 777-200ER and compares tothe 340,500kg MTOW and 13,280km range originally conceived for the aircraft.
It is also significantly better than the improved 344,860kg and 13,900km range of the first production batch to be delivered from April 2004 to the end of the year. These aircraft, offered with improved performance as a result of the initial findings of the flight-test programme, will be upgradeable to the revised standard with minor changes to the nose leg tow bar forged fitting and main landing gear stabilisation brace fuse pins.
The improvement is also obtained without any increases to the operating empty weight (OEW), says 777-200LR/300ER programme manager Lars Andersen. Through design refinements the OEW has been decreased from the original 169,400kg target weight to around 168,700kg. "We've been looking at the loads data and identified only two parts of the aircraft we need to change. We've made it retrofittable because we want this capability by 2004, and also we do not want to hurt the residual value of the early aircraft," Andersen says. Take-off field length is expected to be 3,200m (10,500ft) against 3,080m for the April 2004 version, still an improvement over the 3,290m take-off length originally predicted for the -300ER.
The company is studying how the improvements "might read across to the -200LR", he adds. This ultra-long-range variant is due to enter service in January 2006.
Flight tests of the 777-300ER are meanwhile drawing to a close after 1,250 flight test hours have been accumulated from a total of around 1,500h. The recent extended-range operations flights have seen the aircraft operating into remote airfields, including the polar route diversion airport at Yakutsk in northern Russia.
Source: Flight International
