Guy Norris/SEATTLE

Boeing expects the first of the Next Generation 737 models, the -700, to be given long-awaited European certification by "mid- to late-January" when final tests are conducted on the first European production-standard -700, which is destined for Maersk Air of Denmark.

The tests centre on the revised emergency-exit design, which was developed to satisfy the Joint Aviation Authorities in efforts to clear European-registered aircraft to seat 149 people in the 737-600 and 189 in the -800. All these tests are complete, with the exception of the final evaluation of the exits on the first production-standard aircraft.

The Maersk aircraft is to be flown at the end of this month. It will be used for the test, which involves operation of the exits on the ground after a cruise and "cold soak" at 41,000ft (12,500m).

"We passed all the other JAA tests with lots of margin," says 737-600/700/800 chief project engineer Pete Rumsey, who remains confident that the final evaluation "-should go well". Boeing originally intended to pursue joint US Federal Aviation Administration/ JAA certification, but "the door change forced the two efforts apart", says Rumsey. "When it comes to the -800 certification in March, and the -600 six months after that, we will be back where we were before and will do both JAA and FAA certifications together." The -900, due to be flown in 2000, will be subject to the same process.

Flight tests of the -800 are meanwhile "75% complete", says Rumsey, while the first -600 was rolled out at Boeing's Renton site on 8 December. The low-emissions CFM International CFM56-7B engine for the Next Generation 737 and, for -600 launch customer SAS in particular, has also been certificated by the FAA and the French DGAC.

The CFM56-7B/2, as it is designated, is fitted with a dual annular combustor to cut emissions. Boeing also plans to begin offering airlines the higher-thrust-rated 120kN (27,000lb) -B27 version for the -800 and -900 from 1998 onwards. To date, the Next Generation 737 has been offered with the CFM56-7B18, B20, B22, B24 and B26 powerplants.

Meanwhile, the first -700 was finally handed over to launch customer Southwest Airlines on 17 December - just over a year after programme roll-out, but around two months later than originally scheduled. The final delay was caused by the need to "fine-tune" the lateral-control trim system. "We don't have that much experience with this aircraft yet, which is why it took longer than expected," explains Rumsey. "We're still learning what to do with it." The aircraft is modified with the late design changes. These include the strengthened horizontal-stabiliser trailing-edge panel and beam. Cracks were found in test aircraft which had exceeded maximum operating speed, and the strengthened parts were tested by diving at maximum dive speed, plus 10kt (18km/h), or roughly 410kt.

Another problem with interference of the VHF radios (restricted to a Southwest-specific operating frequency) was resolved by limiting the use of one of the two lower antennas to the airborne communications addressing and reporting system only. The problems were traced to electromagnetic emissions from the electronics bay and engine pylons.

Source: Flight International