Page:Civil Aeronautics Board accident investigation report, National Airlines Flight 2511.pdf/5

 from Kure Beach. Except for these two pieces all the rest of the structure recovered from this compartment was located at the main crash site. There was no evidence of fire or vapor explosion, and no arcing of electrical wiring in the hydraulic compartment area.

All flight logs for a six-month period prior to the accident were reviewed. Items affecting airworthiness were cross-checked against the inspection supplements to determine corrective action.

All inspection supplements for the six-month period were studied for air-worthiness items such as cracks, corrosion, rigging, fuel leaks, seeps and/or stains. Malfunctions of the hydraulic system, flight surfaces, cabin heater system, air conditioning, and pressurization system over the previous six months were also reviewed.

All Airworthiness Directives, Engineering Orders, and Manufacturer's Service Bulletins applicable to N 8225H were reviewed for compliance and were found to be current. All engine records and the last overhaul records were reviewed. The propeller records were researched back to the date the propellers were received by National Airlines.

The comprehensive study of the maintenance records and maintenance history of N 8225H, its engines, and propellers revealed no data that could be related to any structural weakness or deterioration.

The Pratt and Whitney R-2800-CB16 engines installed on N 8225H sustained severe impact damage and were recovered on the outer perimeter of the wreckage area. They were widely separated from the area which contained the forward and aft fuselage sections.

Nos. 1 and 2 engine assemblies remained attached to the left wing until ground impact, at which time they broke off. They were recovered, severely impact damaged, from water-filled craters approximately 1,900 feet from the forward and aft sections of the fuselage and in the opposite direction from the locations of powerplants Nos. 3 and 4.

The Nos. 1 and 2 powerplant assemblies showed no evidence of fire in flight or of burning after impact. The accessory section and the nacelle structure of No. 2 engine did, however, show light soot deposits.

The Nos. 3 and 4 powerplant assemblies were located approximately 2,150 and 2,025 feet, respectively, from the area containing the forward and aft fuselage sections. These two powerplant assemblies had separated from the right wing with their nacelle structures still attached to the engine and mount assemblies.

No. 3 engine was recovered in a nosedown and inverted position in a crater approximately four feet deep. Severe fire damage was found to the rear section of this engine. The lower inboard and outboard sections of the antidrag cowling were detached at impact and were found approximately 25 feet from the engine. Both these cowl sections were found to be moderately sooted on their inside surfaces. The nacelle