Aircraft Accident/Incident Report

Miami, Florida 33266
Sunday, October 3, 1993 15:55 EDT

NTSB Narrative Summary Released at Completion of Accident

THE WATER HEATER IN THE FORWARD GALLEY EXPLODED. EXAMINATION REVEALED THAT THE CONTACTS OF THE WATER HEATER RELAY, WHICH, WHEN ENERGIZED, PROVIDES ELECTRICAL POWER TO THE 3 HEATER ELEMENTS, WERE ROUGH, RAGGED, DISCOLORED, AND SHOWED EXCESSIVE EROSION. ACCORDING TO THE MANUFACTURER, WHEN A RELAY EXCEEDS ITS LIFETIME, IT IS POSSIBLE FOR EROSION AND WEAR ON THE SURFACE TO CAUSE THE CONTACTS TO STICK IN THE CLOSED POSITION. IN ADDITION, THE PRESSURE RELIEF VALVE, WHICH IS DESIGNED TO CRACK AT 65 PSI, WAS TESTED TO 300 PSI WITHOUT CRACKING. UPON DISASSEMBLY, THE O-RING WAS FOUND TO HAVE MIGRATED FROM ITS NORMAL LOCATION INTO THE LOWER VALVE BODY WHERE IT LODGED BETWEEN THE INSIDE DIAMETER AND THE HEAD OF THE POPPET. IN THIS CONDITION, THE O-RING PRESENTED A COMPLETED FLOW BLOCKAGE AND PREVENTED THE PRESSURE RELIEF VALVE FROM OPENING.

NTSB Probable Cause Narrative

THE FAILURE OF THE WATER HEATER RELAY AND THE OVERPRESSURE RELIEF VALVE TO OPERATE PROPERLY. IN ADDITION, THE DESIGN OF THE RELIEF VALVE WAS INADEQUATE IN THAT IT ALLOWED THE O-RING TO MIGRATE FROM ITS NORMAL POSITION PREVENTING THE VALVE FROM OPENING.

Event Information

Type of Event Accident
Event Date 10/3/1993
Event Day of the Week Sunday
Time of Event 1555
Event Time Zone Eastern Daylight Time
Event City MIAMI
Event State FLORIDA
Event Country --
Zipcode of the event site 33266
Event Date Year 1993
Event Date Month 10
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 Full
Investigator's weather source Weather Observation Facility
Time of the weather observation 1550 Eastern Daylight Time
Direction of event from weather observation facility (degrees) 350
Weather Observation Facility ID MIA
Elevation of weather observation facility 16
Distance of event from weather observation facility (units?) 100
Time Zone of the weather observation EDT
Lighting Conditions Day
Lowest Ceiling Height 14000
Lowest Non-Ceiling Height 9000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 7
Air Temperature at event time (in degrees celsius) 26
Dew Point at event time (in degress fahrenheit) 23
Wind Direction (degrees magnetic) 330
Variable Wind Indicator Unknown
Wind Speed (knots) 5
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Serious
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 80
Injury Total Serious 1
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 6030
NTSB Notification Source --
NTSB Notification Date Oct 3 1993 12:00AM
NTSB Notification Time 1645
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 1:42PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number 9YTHR
NTSB Number MIA94FA001
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 129: Foreign
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion In-flight
Aircraft Manufacturer's Full Name MCDONNELL DOUGLAS
Aircraft Model MD-83
Aircraft Series Identifier MD-83
Aircraft Serial Number 49568
Certified Max Gross Weight 160000
Aircraft Category Airplane
Aircraft Registration Class Foreign Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 138
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Sep 12 1993 12:00AM
Airframe hours since last inspection 162
Airframe Hours 14657
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name BRITISH WEST INDIES
Aircraft Owner Street Address ADMIN BLDG PIARCO
Aircraft Owner City TRINIDAD
Aircraft Owner State OF
Aircraft Owner Country
Aircraft Owner Zipcode 00
Operator is an individual? --
Operator Name BRITISH WEST INDIES
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address ADMIN BLDG PIARCO
Operator City TRINIDAD
Operator State OF
Operator Country
Operator Zip code 00
Operator Code BWIA
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 International
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 1520
Departure Time Zone EDT
Destination Same as Local Flt --
Destination Airport Code TBPB
Destination City BARBADOS
Destination State OF
Destination Country
Specific Phase of Flight Climb
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Feb 16 2001 12:38PM
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 --