Aircraft Accident/Incident Report

Richmond, Bc Canada
Friday, August 27, 2004 11:30 PDT

NTSB Narrative Summary Released at Completion of Accident

The flight crew reported hearing a "grinding noise" during initial flap retraction after takeoff. A flight attendant subsequently notified the flight crew that there was a loud "hum and vibration" coming from the right wing. The captain instructed the flight attendant to scan the wing for any anomalies. The flight attendant notified the crew of damage to the wing's leading edge. The flight crew immediately diverted to Seattle, Washington, and performed a normal landing. A post event assessment of the slat by United Airline's engineering staff said "while there is no evidence of bird remains, it is our opinion that the damage was due to impact following takeoff, most likely bird, with subsequent damage caused by flight loads. The crew did not observe birds in the area. The characteristic of the damage does not lend itself to fatigue/delamination of the slat as cause." This incident was delegated to the NTSB by the Canadian TSB.

NTSB Probable Cause Narrative

The slat was impacted by birds after takeoff and subsequently the slat delaminated due to flight loads.

Event Information

Type of Event Incident
Event Date 8/27/2004
Event Day of the Week Friday
Time of Event 1130
Event Time Zone Pacific Daylight Time
Event City Richmond, BC
Event State --
Event Country CANADA
Zipcode of the event site --
Event Date Year 2004
Event Date Month 8
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 472640N
Event Location Longitude 1221952W
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 --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Full
Investigator's weather source Weather Observation Facility
Time of the weather observation 1156 Pacific Daylight Time
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID SEA
Elevation of weather observation facility 433
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 4000
Lowest Non-Ceiling Height 1900
Sky/Lowest/Cloud Conditions Thin Broken
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 17
Dew Point at event time (in degress fahrenheit) 13
Wind Direction (degrees magnetic) 230
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 5
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.27
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 130
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 17055
NTSB Notification Source NW FAA ROC
NTSB Notification Date Aug 27 2004 12:00AM
NTSB Notification Time 1300
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Dec 28 2004 12:45PM
User who most recently changed record NTSB\JOHB
Basic weather conditions Visual Meteorological Cond
FAA District Office Seattle, WA

Aircraft Involved

Aircraft #1

Aircraft Registration Number N526UA
NTSB Number SEA04IA175
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? Yes
Damage Minor
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Boeing
Aircraft Model 757-200
Aircraft Series Identifier --
Aircraft Serial Number 24994
Certified Max Gross Weight 240000
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 193
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Jul 24 2003 12:00AM
Airframe hours since last inspection 3485
Airframe Hours 45605
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name United Airlines
Aircraft Owner Street Address P.O. 66100
Aircraft Owner City Chicago
Aircraft Owner State IL
Aircraft Owner Country USA
Aircraft Owner Zipcode 60666
Operator is an individual? No
Operator Name --
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City --
Operator State --
Operator Country --
Operator Zip code --
Operator Code UALA
Owner has at least one certificate --
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Scheduled
Indicates Domestic or International Flight International
Operator carrying Pax/Cargo/Mail Passenger/Cargo
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code YVR
Departure City Vancouver, BC
Departure State --
Departure Country CA
Departure Time 1116
Departure Time Zone PDT
Destination Same as Local Flt --
Destination Airport Code ORD
Destination City Chicago
Destination State IL
Destination Country USA
Specific Phase of Flight Cruise - normal
Report sent to ICAO? No
Evacuation occurred No
Date of most recent change to record Oct 26 2004 4:12PM
User who most recently changed record STAM
Since inspection or accident Time of Accident
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --