The airline transport pilot reported that the North American B-25 was flying about 155 mph and 1,000′ above ground level. Upon entering the left downwind leg of the traffic pattern of an airport in Dallas, the pilot extended the landing gear.
While the gear was in transit, the crew felt a jolt, as if a bird had hit the front of the airplane.
The pilot made a normal landing, parked the airplane, and noted damage to the left horizontal stabilizer and elevator.
A crew from another airplane reported to the pilot that they observed an object depart the accident airplane during landing gear extension.
A post-accident examination revealed that the left inboard landing gear door separated in flight and hit the engine nacelle, left horizontal stabilizer, and elevator.
The landing gear door was later found in a residential neighborhood about one mile north of the airport.
The gear door was equipped with two arresting cables that were intended to prevent the door from hyperextending. The arresting cables were not installed in the correct position, and the investigation could not determine how long the arresting cables had been incorrectly installed.
The landing gear door connecting rod was bent and fractured into two pieces at the safety wire drill hole. The fractured connecting rod was consistent with an overstress failure in bending.
If the arresting cables had been installed correctly, it is likely that the landing gear door would not have separated from the airplane when the connecting rod failed.
Probable cause: The overstress failure of the landing gear connecting rod and the improper installation of the arresting cables, which allowed the landing gear door to depart in flight and impact the airplane.
NTSB Identification: CEN17LA033
This October 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
