Graham Warwick/PHOENIX

Honeywell has delayed certification of its AS900 turbofan family to early next year, to incorporate durability and maintainability improvements. The slip is not expected to delay certification of the engine's two applications, the BAE Systems Avro RJX regional jet and Bombardier Continental business jet.

Certification of the 7,000lb (31kN) thrust-class turbofan has been delayed from September to the first quarter of 2002 for the AS977 powering the RJX, and the second quarter of next year for the AS907 powering the Continental. The engines are identical apart from the nacelle, accessory gearbox and control software.

The certification was originally planned for March, but was pushed back to September by delays with the integrated powerplant system supplied by GKN Aerostructures. BAE and Bombardier agreed to the further slippage to give Honeywell time to incorporate the improvements that were identified during testing before the engine enters service.

"The engine is meeting its specific fuel consumption and temperature margin specifications, but we have identified a handful of areas where we need to incorporate durability and other improvements before it goes into service," says AS900 general manager Mike Redenbaugh.

He says Honeywell will deliver certificated engines to its customers to meet their aircraft certification schedules. Engines incorporating the improvements will be available for the final 150h certification tests in the fourth quarter.

Improvements identified during the first 4,500h of testing include: individually replaceable fan stator vanes; combustor cooling changes to increase durability; and bleed duct optimisation to reduce losses.

Honeywell has completed almost 6,000h of the 10,000h planned in the AS900 programme. The RJX first flew in April and the Continental is expected to fly in mid-year.

Source: Flight International