Bombardier CL-600-2B1 N857AS

Summary

On 11 June 2009 at about 22:40 local time, a Bombardier CL-600-2B1 registered N857AS, operated by Atlantic Southeast Airlines, was involved in an incident near Atlanta, Georgia, United States. 22 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

11 June 2009 at 22:40

Classification

Incident

Location

Atlanta, Georgia, United States

Nearest airport

Hartsfield Jackson ATL Inter. (ATL)

Coordinates

33.6367, -84.4281

Aircraft

Bombardier CL-600-2B1

Registration

N857AS

Category

Airplane

Engines

2

Operator

Atlantic Southeast Airlines

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Columbus → Atlanta

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

ERA09IA338

Nobody was injured.

The failure of the left main landing gear to extend due to high levels of particulate contamination in the hydraulic fluid.

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

Read the full NTSB narrative

While configuring the airplane for landing, the left main landing gear light indicated that it was not down and locked. The flight crew accomplished the landing gear abnormal procedures, including recycling the landing gear once. The left main gear continued to indicate unsafe, and the captain landed the airplane. After touching down on the right main and the nose gear, the captain used right aileron to keep the left wing up as long as possible. The left wing eventually dropped to the runway and the airplane came to a stop at the runway’s left edge. During recovery of the airplane, the left main gear was partially extended, and no physical obstructions were observed that would prevent the gear from extending. Loosening a hydraulic line to the left main gear actuator allowed the gear to fall into the extended and locked position. The airplane was examined and the landing gear was cycled numerous times using the normal and alternate extension methods. The examination failed to duplicate the incident conditions; the gear extended and retracted normally without hesitation or binding. All major components of the main landing gear system, including the left main landing gear, left gear door, hydraulic pumps, valves and actuators were examined at the manufacturers’ facilities. Although some minor anomalies were noted, no evidence was found to explain the failure of the gear to extend. Analysis of fluid from the numbers 2 and 3 hydraulic systems revealed that the fluid exceeded the maximum particle contamination limits. The system 3 sample also contained metallic particles. Hydraulic system 3 powers gear extension and retraction. After the incident, the operator enhanced its maintenance procedures for testing hydraulic fluid to include contamination. The operator also added verbiage to its pilot procedures to further explain that, in certain cases, it is appropriate to make several attempts at normal gear extension and provided more explanation and guidance regarding the use of the back-up (freefall) system.

Quoted verbatim from the NTSB record.