With production and certification agreements in place, only the customers are missing

Jet Engineering of California has received US Federal Aviation Administration certification for an engine exhaust nozzle that will make Boeing MD-80 series twinjets compliant with International Civil Aviation Organisation Chapter 4 noise limits.

"We have a supplemental type certificate and we have an agreement with JET Engineering to proceed. All we need now is launch customers," says Rod Manion of Goodrich, which has teamed with JET to offer the MD-80 nozzle programme. European MD-80 operators, which are seen as key candidates for the modification, are poised to order the nozzle, but have asked for technical approval from Pratt & Whitney before committing, adds Manion. The engine maker is to study the nozzle to ensure it will not have long-term negative effects on the JT8D-200.

There are over 1,100 MD-80s, of which around 1,000 are active, with most flying in North America (580) and Europe (290). Owners and operators such as GE Capital Aviation Services, Scandinavian Airlines (SAS) and Spanair have all sought data on the nozzle, which has demonstrated cumulative noise reductions of around 10dB.

A 100h flight-test effort on an MD-81 and ground tests have revealed unexpected specific fuel consumption savings of 2-3% at cruise and a 10°C (50°F) lower exhaust gas temperature (Flight International, 1-7 October 2002). The 12-fluted Inconel nozzle weighs 17kg (38lb) and attaches to the Goodrich-made thrust reverser and adds around 180mm (45in) to the overall length of the engine.

"Initial indications are that there will be no need for additional tests by P&W," says Manion, who is optimistic that first modifications could be under way by the end of the year. "We will bring in customer airline rotable units and modify them," says Manion.

He adds that the company plans to produce a minimum of 12 shipsets a month.

Manion says MD-80 operators are "anxious [for the nozzle] because MD-80 values are plummeting and a real benefit in the long term is fleet-value assessment". Approval, for MD-80s up to a maximum take-off weight of 70,370kg, does not include the heavier MD-83 option.

Source: Flight International