Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
San Francisco, California 94128
Monday, June 11, 1984 21:30 PDT
NTSB Narrative Summary Released at Completion of Accident
JUST INSIDE THE OUTER MARKER, A 'LOUD BANG' WAS HEARD & LEFT AILERON INPUT WAS NEEDED TO CONTROL ACFT HEADING. THE LANDING WAS MADE WITHOUT INCIDENT UNTIL THE FLAPS WERE RAISED WHILE TAXIING & THE FLT ENGINEER REPORTED A #4 HYDRAULIC SYSTEM FAILURE. THE CAPT LOST BRAKES AND HAD TO UTILIZE STANDBY BRAKES. AT THIS TIME A SPLIT FLAP INDICATION WAS OBSERVED. INSPECTION REVEALED FLAP TRACK FRACTURED APRX 6 INCHES AFT OF THE FORWARD ATTACH POINT. THE FRACTURE INITIATEDON OUTBOARD FLANGE #1 BOLTHOLE WALL BECAUSE OF PITTING CORROSION. A PORTION OF THE FORE FLAP & A SMALL WING PANEL SEPARATED FROM THE ACFT. DURING FLAP RETRACTION AFTER LANDING, THE TRANSMISSION BALL NUT JAMMED. THE DRIVE TORQUE TUBE FRACTURED AT THIS TIME AND THE BROKEN END OF THE ROTATING TORQUE TUBE DAMAGED HYDRAULIC LINES, CAUSING A LOSS OF HYDRAULIC FLUID. AN ALERT SERVICE BULLETIN WAS ISSUED BY BOEING AFTER THIS INCIDENT & UNITED AIRLINES INITIATED A FLEET WIDE INSPECTION.
NTSB Probable Cause Narrative
Not Yet Reported
Event Information
| Type of Event | Incident |
| Event Date | 6/11/1984 |
| Event Day of the Week | Monday |
| Time of Event | 2130 |
| Event Time Zone | Pacific Daylight Time |
| Event City | SAN FRANCISCO |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 94128 |
| Event Date Year | 1984 |
| Event Date Month | 6 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | |
| Event Location Nearest Airport ID | |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 0 |
| Degrees magnetic from airport | 0 |
| Airport Elevation | 0 |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 2053 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | 190 |
| Weather Observation Facility ID | SFO |
| Elevation of weather observation facility | 11 |
| Distance of event from weather observation facility (units?) | 5 |
| Time Zone of the weather observation | PDT |
| Lighting Conditions | Dusk |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| 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) | 13 |
| Dew Point at event time (in degress fahrenheit) | 7 |
| Wind Direction (degrees magnetic) | 280 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 25 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Not Gusting |
| 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 | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 4 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 5119 |
| NTSB Notification Source | -- |
| NTSB Notification Date | -- |
| NTSB Notification Time | 0 |
| Fiche Number and/or location -used to find docket information | 25003 |
| Date of most recent change to record | Jan 2 2001 9:15AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N4712U |
| NTSB Number | LAX84IA350 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | -- |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOEING |
| Aircraft Model | 747-122 |
| Aircraft Series Identifier | 747-122 |
| Aircraft Serial Number | 19757 |
| Certified Max Gross Weight | 775000 |
| 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 | 429 |
| Number of Engines | 4 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | AAIP |
| Date of Last Inspection | Jan 27 1984 12:00AM |
| Airframe hours since last inspection | 1178 |
| Airframe Hours | 45436 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | BANKER TRUST CO. TRUSTEE |
| Aircraft Owner Street Address | 318 CHURCH ST. STATION |
| Aircraft Owner City | NEW YORK |
| Aircraft Owner State | NY |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | |
| Operator is an individual? | -- |
| Operator Name | UNITED AIRLINES |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | P O 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 Only |
| Type of Flying (Per_Bus / Primary) | Unknown |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | HNL |
| Departure City | HONOLULU |
| Departure State | HI |
| Departure Country | |
| Departure Time | 1640 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | SFO |
| Destination City | SAN FRANCISCO |
| Destination State | CA |
| Destination Country | |
| Specific Phase of Flight | Approach |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Dec 20 2002 12:42PM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 0 |
| Runway Length | 0 |
| Runway Width | 0 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |