Pilot Debrief

Boeing 767 near Los Angeles, CA — 2020-08-19

Final reportDCA20LA138
Sign in to save
Date
2020-08-19
Location
Los Angeles, CA, USA
Airport
KLAX
Aircraft
Boeing 767
Registration
N146FE
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Approach

Probable cause

The left main landing gear’s failure to extend due to the separation of the brake rod retaining hardware from the aft inboard wheel for reasons that could not be determined based on the available evidence.

NTSB narrative

In preparation for landing, LAX air traffic control cleared FedEx flight 1026 for an instrument landing system (ILS) approach to runway 24R. When the airplane descended to an altitude of about 1,800 ft, the flight crew moved the landing gear handle to lower the landing gear. The crew then received a “GEAR DISAGREE” message from the engine indicating and crew alerting system. The crew discontinued the approach and climbed the airplane to 5,000 ft to perform the quick reference handbook Gear Disagree checklist procedure. The checklist directed the crew to lower the landing gear using the alternate gear extension system, but the left main landing gear (MLG) still did not extend. The flight crew then flew a low approach to the runway so that the tower controller could try to see if the left MLG was extended. The airplane descended to an altitude of about 500 ft above ground level, but the tower controller could not tell whether the left MLG was extended. The crew then declared an emergency and flew another low approach—this time at an altitude of about 200 to 300 ft above ground level and with airport operations personnel positioned along the runway to get a better view of the airplane. The second low approach determined that the left MLG was retracted. The captain stated that, once the fuel was at an appropriate point to execute the gear-up approach and landing, air traffic control vectored the airplane for an ILS approach to the longest runway at the airport. The captain also stated the airplane made a “normal landing touchdown” and that, after the left engine contacted the runway, he maintained directional control with the ailerons, rudder, and right wheel braking. After the captain manually deployed the speedbrakes, the airplane came to a stop on the runway centerline about 2,000 to 3,000 ft from the end of the runway. A brake rod, which is installed between each brake assembly housing and the shock strut, transfers the torque generated by the brake to the MLG. Each brake rod is connected to the torque arm on the brake assembly housing using, among other things, a pin that is secured by a retaining bolt. Postaccident examination of the left MLG assembly revealed that the No. 6 brake rod (corresponding to the aft inboard wheel) was connected at the shock strut end but was not connected to the torque arm on the brake assembly housing. The brake rod pin was likely in place during the accident flight takeoff given that no scrape marks or gouging were found on the brake rod, indicating that the brake rod had not contacted the runway while the airplane was moving, which would likely have happened if the brake rod was connected only at the shock strut end while the left MLG was in its extended position. The flight crew was unable to extend the left MLG during the approach because the pin had come loose during the flight, which allowed the brake rod to move out of its normal position and become hung up on the landing gear upstop. The airplane had accumulated 73 flight cycles since the last No. 6 brake assembly change, which would have been the last time that the No. 6 brake rod was removed and reinstalled. The maintenance personnel who performed the No. 6 brake assembly change did not recall anything unusual or concerning about the installation of the brake assembly or brake rod. The No. 6 brake rod attaching hardware components from the accident airplane were not located after the accident, precluding a determination of why the pin was in place for the takeoff but not when the crew tried to lower the landing gear. As a result, on the basis of the available evidence for this accident, the investigation was unable to determine the reason that the brake rod pin came loose during the accident flight.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Crew could have aborted the approach earlier after the GEAR DISAGREE message.

NTSB coding

Evidence available

  • 5 docket documents
View NTSB final reportView NTSB docket

Docket documents5

Related mishaps