CONTROLLED FLIGHT INTO TERRAIN: LOSS OF ATTITUDE HEADING REFERENCE SYSTEM
This accident is where loss of vacuum (older planes) or loss of attitude display (newer planes) causes the pilot to have very little pitch and bank information, or in some cases none at all.
The old school name for this was called partial panel flying and IFR rated pilots received training and check ride evaluation on their ability to fly while under IMC (real or simulated) conditions with loss of Attitude,
Heading reference System (AHRS) In later model more advanced aircraft there is an actual unit called the AHRS hardware that generates gyroscopic information that is then sent to the display.
In electronic aircraft, either the AHRS unit or the display itself could fail while in IMC conditions, and require the pilot to be able to fly and navigate on remaining data.
SOLUTION:
In today’s electronic world, numerous affordable options are available that will give both navigation and basic ADI information to the pilot. The non AHRS portable devices use GPS data to generate cockpit instrumentation that show basic primary flight instruments.
The AHRS based portable electronic instruments use an actual portable AHRS unit to generate this information and send it to the portable device. You may have seen these devices sitting on the glare shield of some airplanes in the last few years.
Get with your CFI or best safety pilot and practice flight under a view limiting device by sole reference to a portable device for all information. This takes some time to get used to, so practice this often. Then review. You will improve.
SAMPLE ACCIDENT REPORT:
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to control the airplane while maneuvering because of spatial disorientation. Contributing to the accident were the failure of the airplane's primary attitude indicator and the adverse weather conditions, including turbulence. Accident Number: CHI01MA011.