Guy Norris/BEVERLEY HILLS
BOEING IS considering use of the experimental propulsion-controlled aircraft (PCA) concept as a back-up flight-control system on the next-generation 747-500/600X, following the company's decision to adopt fly-by- wire (FBW) flight controls.
NASA, which completed successful flight tests of the PCA system in 1995 on a modified Mc- Donnell Douglas (MDC) MD-11, says that Boeing is talking about using the system in lieu of a mechanical back-up to the FBW system.
The PCA system provides flight control by interpreting flight-director commands and adjusting engine power through the full-authority digital engine-controls. Lacking any mechanical linkages, the system would save weight over mechanical back-up controls and could be embedded as software in the aircraft's avionics.
NASA, meanwhile, has completed a study for MDC into the use of the PCA system on MDC's C-17 transport. The PCA system was developed by a NASA-led team which included Honeywell, MDC and Pratt & Whitney.
Source: Flight International
