North American TB-25N N9079Z

Summary

On 4 September 2011 at about 21:45 local time, a North American TB-25N registered N9079Z, operated by RAG Wings & Radials Aircraft Leasing LLC, was involved in an accident near Georgetown, Delaware, United States. 5 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

4 September 2011 at 21:45

Classification

Accident

Location

Georgetown, Delaware, United States

Nearest airport

Sussex County Airport (GED)

Coordinates

38.6861, -75.3550

Aircraft

North American TB-25N

Registration

N9079Z

Category

Airplane

Engines

2

Operator

RAG Wings & Radials Aircraft Leasing LLC

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Patuxent River → Georgetown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA11LA484

Nobody was injured.

Maintenance personnel's inadequate examination of the main landing gear during the airplane’s most recent conditional inspection, which resulted in the fatigue failure of the right main landing gear shock strut drag arm during the landing roll.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

According to both pilots, they landed the airplane and felt the right wing drop during the landing roll. They attempted to maintain directional control, but the right wing dropped further and the airplane veered off of the right side of the runway. During a subsequent examination of the wreckage, the right main landing gear shock strut drag arm was found broken. An examination of the broken drag arm revealed that it fractured in the I-beam at the blend radius of an orthogonal arm due to bending fatigue. Given the extent of fatigue crack propagation in the flange of the I-beam, it is likely that the fracture occurred due to high-cycle, low-stress fatigue. Since the depth of the fatigue crack was significant relative to the I-beam flange thickness, the fatigue crack probably developed and propagated over a long time under numerous low-stress cycles. The most recent inspection of the main landing gear was on July 7, 2011, which was in accordance with a conditional inspection. The inspection required a mechanic to verify the condition and security of the main landing gear. It is most likely that the fatigue crack would have been detectable at the time of that inspection.

Quoted verbatim from the NTSB record.