Boeing 737-790 N614AS

Summary

On 19 October 2006 at about 08:00 local time, a Boeing 737-790 registered N614AS was involved in an incident near Los Angeles, California, United States. 5 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

19 October 2006 at 08:00

Classification

Incident

Location

Los Angeles, California, United States

Coordinates

Not recorded

Aircraft

Boeing 737-790

Registration

N614AS

Category

Airplane

Engines

2

Operator

Not recorded

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Los Angeles → Mexico City

Aircraft damage

Not recorded

Weather

VMC

Light

Night

NTSB number

LAX07IA014

Nobody was injured.

A complete failure and depressurization of both hydraulic systems due to two separate events: 1) the failure of a engine driven pump on the 'A' system, and 2) the fatigue fracture and failure of a hydraulic line on the 'B' system.

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

Read the full NTSB narrative

During cruise flight, just after entry into foreign airspace, the flight crew was alerted to a System B hydraulic failure, and they decided to return to, and land in the United States (US). Upon re-entry to US airspace, the flight crew declared an emergency and requested to land at the departure airport. On final approach, about 5 minutes after selecting flaps to 15 and lowering the landing gear, the flight crew was alerted to the System A hydraulic quantity gage, that had dropped to 0 pounds per square inch (psi). At this point both System A LOW PRESSURE LIGHTS illuminated and the airplane went into the manual reversion mode. The flight crew indicated that the airplane was difficult to control; however, they landed uneventfully at the airport. Maintenance personnel for the airline, and the airplane manufacturer, inspected the hydraulic systems. They noted that the initiating event was a failed engine driven pump. The secondary event was a cracked hydraulic line that failed due to fatigue. A metallurgical examination revealed the fatigue fracture initiated at the toe of the welding root where they were able to locate a crack that had propagated through half the perimeter. The airframe manufacturer redesigned the affected tube, part number 272A4451-87, a titanium tube, with part number 272A4451-200, a stainless steel tube.

Quoted verbatim from the NTSB record.