NTSB Factual Report

On August 31, 1998, about 1035 eastern daylight time, a Boeing 727-200, N722DH, operated by DHL Worldwide Express as flight 1165, experienced a failure of the right main landing gear (MLG) shortly after making an emergency landing at John F. Kennedy International Airport, Jamaica, New York. The flight was operating under 14 Code of Federal Regulations Part 121 as a regularly scheduled cargo flight from New York to Cincinnati, Ohio. Shortly after takeoff, the No. 2 engine failed and shutdown procedures for the No. 2 engine were accomplished. The flight crew declared an emergency and requested to return to the airport. On approach,

an engine out go-around was required as ATC had instructed the flight crew of a B-747 to "position and hold" on the end of the runway. The first officer was the pilot flying. Following an uneventful[Haueter Tom] go around and touchdown, as the airplane slowed to about 80 knots, the captain took control of the airplane. Shortly thereafter, the right MLG collapsed and the airplane slid to a stop on the runway. None of the three flight crewmembers and two jumpseat passengers aboard were injured.

Examination of the No. 2 engine revealed that 80 percent of the main fuel pump main drive shaft was worn to the spline root. The examination also revealed that the grease used to lubricate the main drive shaft output splines was not the authorized grease specified per OHM 73-11-1 or MIL-G-81322. Additionally, the magnetic seal compression O-ring that rides on the drive gear journal outer diameter was hardened and exhibited inner diameter axial cracks.

The component manufacturer indicated that the failure of the magnetic seal was the first such reported incident in 30 years; however, it agreed to review operational data from airlines to reevaluate the mean time between overhaul intervals for the seal and to recommend an inspection interval, as necessary.

Examination of the right MLG revealed a fracture failure of the trunnion bearing support fitting that was caused by fatigue cracking and stress corrosion cracking.

As a result of this accident, the Safety Board issued Safety Recommendation A-99-4, which asked the Federal Aviation Administration to "require operators of all Boeing 727 series airplanes to (1) conduct periodic ultrasonic inspections of the main landing gear (MLG) forward trunnion bearing support fittings for corrosion, cracks, and stress corrosion cracking; (2) repair or replace these fittings if they are cracked or corroded; and (3) ensure that a proper moisture barrier is applied on new or existing MLG forward trunnion bearing support fittings to minimize corrosion."

On October 2, 2001, the Federal Aviation Administration issued Airworthiness Directive (AD) 2001-20-09. AD 2001-20-09 is applicable to all Boeing 727 series airplanes and requires repetitive ultrasonic inspections of the bearing support fitting of the forward trunnion on the MLG to detect corrosion and cracking, follow-on actions if necessary, and repair/rework of the support fitting.

NTSB Probable Cause

The failure of the right main landing gear caused by fatigue cracking and stress corrosion cracking of the trunnion bearing support fitting.