Individually Owned: 150,657
Corporate Owned: 137,281
Chicago-O'hare Int'l Airport
Aircraft Accident/Incident Report
Chicago, Illinois 60666
Tuesady, April 8, 1986 13:19 CST
NTSB Narrative Summary Released at Completion of Accident
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.
NTSB Probable Cause Narrative
Not Yet Reported
Event Information
| Type of Event | Accident |
| Event Date | 4/8/1986 |
| Event Day of the Week | Tuesday |
| Time of Event | 1319 |
| Event Time Zone | Central Standard Time |
| Event City | CHICAGO |
| Event State | ILLINOIS |
| Event Country | -- |
| Zipcode of the event site | 60666 |
| Event Date Year | 1986 |
| Event Date Month | 4 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | CHICAGO-O'HARE INT'L |
| Event Location Nearest Airport ID | ORD |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | 0 |
| Degrees magnetic from airport | 0 |
| Airport Elevation | 667 |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1332 Central Standard Time |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | ORD |
| Elevation of weather observation facility | 667 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | CST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 3500 |
| Lowest Non-Ceiling Height | 3500 |
| Sky/Lowest/Cloud Conditions | Unknown |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 15 |
| Air Temperature at event time (in degrees celsius) | 12 |
| Dew Point at event time (in degress fahrenheit) | -2 |
| Wind Direction (degrees magnetic) | 300 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 15 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | 1 |
| Injury Total None | 113 |
| Injury Total Serious | -- |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 2698 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Apr 8 1986 12:00AM |
| NTSB Notification Time | 1332 |
| Fiche Number and/or location -used to find docket information | 34465 |
| Date of most recent change to record | Dec 13 2000 3:38PM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N9054U |
| NTSB Number | CHI86FA119 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | Ground |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOEING |
| Aircraft Model | 737-222 |
| Aircraft Series Identifier | 737-222 |
| Aircraft Serial Number | 19935 |
| Certified Max Gross Weight | 100800 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | -- |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | AAIP |
| Date of Last Inspection | -- |
| Airframe hours since last inspection | -- |
| Airframe Hours | 32714 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | UNITED AIRLINES |
| Aircraft Owner Street Address | P.O. BOX 66100 |
| Aircraft Owner City | CHICAGO |
| Aircraft Owner State | IL |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 60666 |
| Operator is an individual? | -- |
| Operator Name | UNITED AIRLINES |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | BOX 66100 |
| Operator City | CHICAGO |
| Operator State | IL |
| Operator Country | |
| Operator Zip code | 60666 |
| Operator Code | UALA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger/Cargo |
| Type of Flying (Per_Bus / Primary) | Unknown |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | OMA |
| Departure City | OMAHA |
| Departure State | NE |
| Departure Country | |
| Departure Time | 1205 |
| Departure Time Zone | CST |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | |
| Destination City | |
| Destination State | |
| Destination Country | |
| Specific Phase of Flight | Landing |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 2 2001 10:30AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 27R |
| Runway Length | 7416 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |