Aircraft crashworthiness studies : findings in accidents involving an aerial application aircraft.

PDFTech ReportFAA-AM-80-3DOT/FAA/AM-80/3Agricultural aviationAircraft accidentsCrashworthinessCrash injuriesRestraint systemsCockpitsSeatsAccident investigationCase studiesUnited StatesCivil Aerospace Medical InstituteKirkham, William R.Simpson, James M.Wallace, Terry F.Grape, Paula M.Civil Aeromedical InstituteUnited States. Office of Aviation MedicineNTL-AVIATION-Aviation Safety/AirworthinessNTL-SAFETY AND SECURITY-AccidentsNTL-SAFETY AND SECURITY-Aviation Safety/AirworthinessUS Transportation CollectionAircraft crashworthiness features are presented, as others have done, in terms of packaging principles. Modern aerial application aircraft are recognized as being the most crashworthy in the civil aviation fleet. Eighteen accidents involving an aerial application aircraft are presented in regard to crashworthiness findings, crashworthiness being the protection afforded by the aircraft against injury to the pilots from impact forces.A summary of findings showed that the cockpit afforded good protection but in many of the accidents pilot restraint systems failed. There were no failures in lap belts or lap belt attachments. The structural attachment of the shoulder harness failed in a rare accident and the manufacturer strengthened the attachment. In three aircraft the inertia reel, to which the shoulder harness was attached, failed, diminishing the effectiveness of the shoulder harness in attenuating impact forces on the pilots. In 14 of the 18 accidents the seat completely or partially separated from the seat track, and in 14 accidents one or more of the cast alloy seat legs or pedestals broke.These accidents illustrate two areas of concern in terms of improved crashworthiness of these aircraft. One is the strength of the attachment of the shoulder harness, and the other is the apparent ease of detachment of seats from the seat tracks and failure (fracture) of the cast alloy seat parts--legs and pedestals in particular