What happened
The aircraft, a PBY-5A, was operating under US Army authorization to retrieve an injured pilot who had bailed out over water. During the recovery operation, the crew attempted a full stall landing in challenging sea conditions characterized by swells ranging from 12 to 15 feet. The impact caused significant structural damage to the bottom of the fuselage, resulting in opened seams and sheared rivets.
The crew initiated emergency procedures by plugging the rivet holes and activating the bilge pump. However, the rate of water ingress exceeded the pumping capacity. Further damage occurred to the hull during an attempted take-off, which made it necessary to abandon the aircraft. The seaplane subsequently sank and was lost. All 12 crew members were rescued from the water with various injuries.
Findings
Investigation into the incident revealed that the aircraft had sustained hull damage in open sea operations on two prior occasions, both of which were repaired. The plane had not undergone a major or intermediate overhaul since these incidents. At the time of the accident, the aircraft carried approximately 600 gallons of fuel, and no attempt was made to reduce weight by removing unnecessary equipment.
The pilot possessed 742 total hours in PBY-5 aircraft, including 105 hours in the PBY-5A variant, but had no prior experience with rough water operations. The Trouble Board noted that the extra weight of the landing gear and the apparent weakness in the hull structure due to wheel wells contributed to the vulnerability of the airframe in such conditions. Recommendations were made to limit crew size and aircraft weight for open sea rescue missions, mandate training in rough water techniques, and restrict the use of PBY-5A models for such operations to extreme emergencies only.