Aircraft Accident/Incident Report

Minneapolis, Minnesota 55425
Monday, May 18, 1998 2:15 CDT

NTSB Narrative Summary Released at Completion of Accident

While troubleshooting a fire warning indication with company maintenance control using the #2 VHF transceiver, the crew experienced several uncommanded 'kicks' of the yaw damper. The crew turned off the upper yaw damper, but not the lower. They continued to experience 'kicks' although not as severe. The flight departed to Minneapolis where it landed uneventfully. Inspection of the airplane after the incident revealed an open shield at the #2 VHF coax connector which is located near the yaw damper control box. The connector was replaced and the airplane was returned to service.

NTSB Probable Cause Narrative

the open shielding on the #2 VHF transceiver coax connector which resulted in electromagnetic interference with the yaw damper system.

Event Information

Type of Event Incident
Event Date 5/18/1998
Event Day of the Week Monday
Time of Event 215
Event Time Zone Central Daylight Time
Event City MINNEAPOLIS
Event State MINNESOTA
Event Country --
Zipcode of the event site 55425
Event Date Year 1998
Event Date Month 5
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 --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Unknown
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Night/Dark
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Unknown
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 0
Air Temperature at event time (in degrees celsius) --
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
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 3
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 5007
NTSB Notification Source --
NTSB Notification Date May 18 1998 12:00AM
NTSB Notification Time 556
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 11:17AM
User who most recently changed record dbo
Basic weather conditions Unknown
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N675UP
NTSB Number CHI98IA164
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage None
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Boeing
Aircraft Model 747-123
Aircraft Series Identifier 747-123
Aircraft Serial Number 20390
Certified Max Gross Weight 734000
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 9
Number of Engines 4
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection May 11 1998 12:00AM
Airframe hours since last inspection --
Airframe Hours 58165
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name UNITED PARCEL SERVICE
Aircraft Owner Street Address 1400 N HURSTBOURNE PKY
Aircraft Owner City LOUISVILLE
Aircraft Owner State KY
Aircraft Owner Country
Aircraft Owner Zipcode 40223
Operator is an individual? --
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 IPXA
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 Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Cargo
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code LOU
Departure City LOUISVILLE
Departure State KY
Departure Country
Departure Time 0
Departure Time Zone
Destination Same as Local Flt --
Destination Airport Code ANC
Destination City ANCHORAGE
Destination State AK
Destination Country
Specific Phase of Flight Cruise
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 --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --