Researchers at NASA’s Dryden Flight Research Center, Edwards, Calif.,
have completed a milestone series of evaluation flights for a
revolutionary flight control system that could enable future aircraft
suffering major system failures or combat damage to be flown to a
safe, controlled landing.

The Intelligent Flight Control System (IFCS) research, aboard a
highly-modified NASA F-15B aircraft, focuses on development of
"self-learning" neural network software for aircraft flight control
computers. In its final form, the software would compare data from
how the aircraft and its systems are operating with a database of how
it would normally operate, and automatically adjust the flight
controls to compensate for any damaged or inoperative control
surfaces or systems.

The IFCS project team successfully met research objectives by
evaluating in flight a passive online Parameter Identification (PID)
algorithm, or software code, and an online learning Dynamic Cell
Structure (DCS) neural network algorithm.

This is a significant step for real time PID and neural net
technology, and serves as a significant proof of technology for the
project’s direct adaptive (Generation I) flight control concept.

"This work marks a significant step toward learning, thinking,
aircraft that will be safer, more autonomous, and more reliable than
ever before," says John Carter, Dryden’s IFCS project manager.

The team assessed the ability of the PID and DCS algorithms to
efficiently identify aircraft stability and control characteristics,
and map and retain this information as a function of flight condition.

The PID algorithm is an on-line function that determines the actual
stability and control characteristics of the aircraft as it flies.
When results from the PID algorithm differ from what is called the
pre-trained neural network (PTNN), an update to the system is

The DCS provides the online learning of the system. It tracks the
differences between the PTNN and PID and provides an organized map of
updates to the stability and control derivatives of the aircraft.

The original DCS Code was delivered from NASA’s Ames Research Center,
Moffett Field, Calif., then modified at NASA Dryden for Generation I

Included among important features of the DCS are the facts that it
has long-term memory, critical for IFCS use, and has the ability to
be enlarged by the addition of nodes.

IFCS software evaluations performed by the F-15B aircraft included
handling qualities maneuvers, envelope boundary maneuvers, control
surface excitations for real-time PID to include pitch, roll, and yaw
doublets, and neural network performance.

– NASA –

Note to Editors:
High resolution photos of the F-15B IFCS aircraft are available on-line at:

For more information, call Gray Creech, NASA Dryden public affairs,
at (661) 276-2662