Boeing 737-222 N9054U

Summary

On 8 April 1986 at about 19:19 local time, a Boeing 737-222 registered N9054U, operated by United Airlines, was involved in an accident near Chicago, Illinois, United States. 114 people were on board and one had minor injuries. The aircraft was substantially damaged. No probable cause statement is available for this record.

Date

8 April 1986 at 19:19

Classification

Accident

Location

Chicago, Illinois, United States

Nearest airport

Chicago-O'hare Int'l (ORD)

Coordinates

Not recorded

Aircraft

Boeing 737-222

Registration

N9054U

Category

Airplane

Engines

2

Operator

United Airlines

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Omaha → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CHI86FA119

1 person had minor injuries.

The NTSB has not published a probable cause for this record. No probable cause statement is present in the source data.

Nothing about the cause is stated here that is not in the source record.

Read the full NTSB narrative

THE LEFT MAIN LANDING GEAR COLLAPSED MOMENTS AFTER TOUCHDOWN. WINDS AS REPORTED BY THE TWR WERE FROM 350 DEGS AT 19 KTS GUSTING TO 29 KTS. THE CAPTAIN AND COPILOT REPORTED THE TOUCHDOWN WAS NORMAL. THE 3 FLIGHT ATTENDANTS SAID THE AIRCRAFT LANDED HARD AND STARTED SHAKING VERY BADLY. THE FLIGHT ATTENDANTS ALSO REPORTED THAT THE PREVIOUS 2 LANDINGS HAD BROUGHT A GREAT DEAL OF VIBRATING/SHAKING TO THE AIRCRAFT. THE LEFT MAIN LANDING GEAR TEE BOLT WAS FOUND SEPARATED. METALLURGICAL EXAMINATION OF THE TEE BOLT SHOWED THE FRACTURE EMANATED FROM A SHALLOW PREEXISTING CRACK IN THE DRAG BRACE BEARING SURFACE RADIUS THAT THE METALLURGIST FOUND TO BE SHARPER THAN DESIRED. THE COLLAPSE OF THE LANDING GEAR IS CONSIDERED RELATED TO THE FRACTURED TEE BOLT. THE SAFETY BOARD IS UNABLE TO DETERMINE WHETHER OTHER EVENTS, CIRCUMSTANCES OR CONDITIONS WERE PRESENT THAT CONTRIBUTED TO THE TEE BOLT FAILURE IN THIS INSTANCE. THE OPERATOR HAS AMENDED THEIR REPAIR SPECIFICATIONS FOR THE TEE BOLTS.

Quoted verbatim from the NTSB record.