Airbus A320 N536JB

Summary

On 22 September 2005 at about 01:18 local time, a Airbus A320 registered N536JB, operated by Jet Blue Airways, Inc., was involved in an incident near Los Angeles, California, United States. 146 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

22 September 2005 at 01:18

Classification

Incident

Location

Los Angeles, California, United States

Nearest airport

Los Angeles International (KLAX)

Coordinates

33.9425, -118.4081

Aircraft

Airbus A320

Registration

N536JB

Category

Airplane

Engines

2

Operator

Jet Blue Airways, Inc.

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Burbank → New York

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

LAX05IA312

Nobody was injured.

The fatigue failure of two anti-rotation lugs due to repeated cyclic pre-landing tests, which allowed the nosewheels to deviate from the 0-degree position on landing gear retraction. A contributing factor was the design of the Brake Steering Control Unit (BSCU) system logic, which prevented the nosewheels from centering. Also contributing was the lack of a procedure to attempt to reset the BSCU system under these conditions.

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

Read the full NTSB narrative

Shortly after the landing gear handle was positioned to the up position in the initial climb, the flight crew noted an error message on the Electric Centralized Aircraft Monitoring (ECAM) system listing a fault (L/G SHOCK ABSORBER FAULT) message for the nose landing gear (NLG) shock absorber. The gear handle was then moved to the down position and the crew received an error message of a fault for the nose wheel steering (WHEEL N/W STRG FAULT). After determining that the nose landing gear was cocked 90 degrees, the crew landed at an alternate airport, and the NLG tires and both wheels were worn down into the axle. Post incident examination of the nose gear assembly found that two of the four anti-rotation lugs on the NLG upper support assembly fractured and separated due to induced fatigue from the stearing system's programed pre-landing dynamic steering tests that repeatedly cycles pressure to the stearing cylinders. The failed lugs allowed the NLG to deviate from its 0-degree position in the landing gear bay upon gear retraction on takeoff. This resulted in the L/G SHOCK ABSORBER FAULT error message on the ECAM system. When the pilots extended the incident airplane's landing gear, the nose gear achieved the down and locked position 1.5 seconds before the main gear and/or all of the landing gear doors closed. The nose wheel assembly was not centered at this time. The Brake Steering Control Unit (BSCU) detected this off center condition of the NLG and attempted to re-center the nose wheel; however, due to the sequencing of the nose and main landing gear and their respective doors, hydraulic pressure was shut off to the NLG steering valve. This lack of hydraulic power to the servo valve resulted in a lack of position feedback to the BSCU. After a 0.5-second monitoring time period, the BSCU detected this as a fault and deactivated the steering system so that the BSCU could not return the nose wheels to center. Failure of the nosewheels to center initiated a WHEEL N/W STRG FAULT caution message on the ECAM. There were no approved procedures that allowed the flight crew to attempt to reset the BSCU system, which would have re-enabled the hydraulic system and could have resulted in the system recentering the nose wheels.

Quoted verbatim from the NTSB record.