Accession Number : ADA326222

Title :   Integrated Simulation of Atmospheric Pressures and Dynamic Forces During Accidental Decompression and Subsequent Emergency Descent of High Altitude Transport Aircraft.

Descriptive Note : Final rept.,

Corporate Author : NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA CREW SYSTEMS DEPT

Personal Author(s) : VON Beckh, Harald J. ; Baas, William P.

PDF Url : ADA326222

Report Date : 03 FEB 1975

Pagination or Media Count : 47

Abstract : These experiments exposed for the first time human subjects simultaneously to decompression events and to mechanical forces. The selected profiles simulated an accidental decompression and subsequent emergency descent of a high altitude/multi Mach transport aircraft. Using the uniquely versatile centrifuge of the Naval Air Development Center, the volunteers, accompanied by on board observers, experienced a simulated take off and climbing flight, including a nose up rotation of 22 degrees, a cruising flight of 20 minutes at 8,000 feet cabin altitude, a decompression up to 37,000 feet within 3 minutes, one minute dwelling time at 37,000 feet, and a linear descent to 8,000 feet within 6 minutes. This decompression profile is identical to 'Limit IV', which is identified as 'worst possible case' in the SST Tentative Airworthiness Standards, Part 25 of the Federal Aviation Administration. The dynamic simulation included a moderate +G sub z load shortly after the decompression event, which simulated the pilot's maneuvers to 'ease' from the cruising flight into the emergency descent and a G sub x load, which simulated the deceleration in the direction of the flight path, due to the decrease of speed from multi-Mach to subsonic values. The ten subjects underwent the experimental conditions in forward facing and rearward facing position. In half of the experiments the overhead mask delivery mode was employed; in the other half the seatback delivery mode. The masks were presented when the cabin altitude reached 12,000 feet. It was shown that a healthy male population (average age 27.7 years) had no difficulties to reach for and don the mask correctly. The average donning time was 12.2 seconds. Earlobe oximetry and the modified number writing test of Lottig did not reveal hypoxic conditions at any time.

Descriptors :   *EMERGENCIES, *DECOMPRESSION, *ELECTROCARDIOGRAPHY, *ACCIDENTS, *SUPERSONIC TRANSPORT AIRCRAFT, *GONDOLAS, TELEVISION SYSTEMS, HIGH ALTITUDE, DYNAMIC LOADS, BAROMETRIC PRESSURE, MASKS, VOICE COMMUNICATIONS, AIRWORTHINESS, DESCENT, SEATS, HYPOBARIC CHAMBERS, CINEMATOGRAPHY.

Subject Categories : Terminal Flight Facilities
      Safety Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE