Airbus A320-232 N431UA

Summary

On 10 October 2007 at about 01:30 local time, a Airbus A320-232 registered N431UA, operated by United Air Lines Inc, was involved in an incident near Chicago, Illinois, United States. 127 people were on board and 2 had minor injuries. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

10 October 2007 at 01:30

Classification

Incident

Location

Chicago, Illinois, United States

Nearest airport

Chicago O'hare Intl (ORD)

Coordinates

41.9686, -87.9078

Aircraft

Airbus A320-232

Registration

N431UA

Category

Airplane

Engines

2

Operator

United Air Lines Inc

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Seattle → Chicago

Aircraft damage

Minor

Weather

VMC

Light

Night

NTSB number

CHI08IA026

2 people had minor injuries.

The misrouted and reversed antiskid wiring by vendor maintenance personnel leading to the runway excursion. Contributing to the incident were the runway sign, the vendor's maintenance personnel not understanding the entire maintenance procedures in the dual tachometer replacement, and the operator's maintenance procedures being unclear to the maintenance personnel.

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

Read the full NTSB narrative

The airplane's left main landing gear inboard and outboard anti skid tachometers wiring were reversed during scheduled maintenance at a vendor. During landing, the inboard left main landing gear's wheels went to a high braking level and the outboard wheel did not apply braking. The airplane sustained minor damage when it exited the runway and impacted runway lighting. Post incident examination of the airplane and brake components revealed no further anomalies. The vendor that performed the scheduled maintenance indicated that their personnel did not understand that the built in test equipment test they performed did not check for cross-wired tachometers. A different specified test called out in the airplane maintenance manual and in an operator's reference document indicated this specified check would verify a cross-wired condition. The operator reported that the reference documentation associated with the scheduled maintenance involving both of the left main landing gear's tachometers was unclear and that the procedure for that maintenance was revised.

Quoted verbatim from the NTSB record.