Aircraft Accident/Incident Report

Thermal, California 92563
Friday, December 25, 1998 13:44 PST

NTSB Narrative Summary Released at Completion of Accident

On a cross-country flight the aircraft entered an uncontrolled descent, impacted a lake, and sank. The wreckage was not recovered; however, both occupants were eventually recovered from the lake over a 2-month period. Review of recorded radar data identified the aircraft as it departed and flew to a point over the lake. About 1343, the target started a high vertical rate descent from 6,500 feet to 3,100 feet, where the mode C report stopped, in 1 minute 36 seconds. The recorded data lost the beacon code at this altitude but two primary targets remained. The last hit was at 1344. Its location was 33 degrees 28 minutes north latitude and 115 degrees 37.9 minutes west longitude over the northern end of the lake. The pilot did not have a pilot certificate or current medical certificate. The date of his most recent application for medical certificate, which was recalled by the FAA, was July 15, 1997. This application listed 800 hours to date and 100 hours in the last 6 months. Numerous medical certificate applications were denied by the FAA throughout the 1980's and early 1990's due to a history of heart problems. His medical records contained a history of heart problems. The autopsy report noted long term atherosclerotic disease in the right coronary artery and a blood clot in the right coronary artery that was several days old. The report noted limited injuries to the upper extremities. The pilot's wife was not a pilot. The autopsy report on the pilot's wife noted substantial upper and lower extremity injuries consistent with control manipulation at impact. The pilot's toxicology report showed Pseudoephedrine and Ephedrine in his tissue samples. Both can result in increased heart rate, constriction of blood vessels, and an increase in blood pressure. The effects could increase the risk of a heart attack in someone with significant coronary artery disease.

NTSB Probable Cause Narrative

The occurrence of an in-flight incapacitating heart rhythm to the pilot. A factor was the pilot's ingestion of over-the-counter medications that made him more susceptible to an abnormal heart rhythm.

Event Information

Type of Event Accident
Event Date 12/25/1998
Event Day of the Week Friday
Time of Event 1344
Event Time Zone Pacific Standard Time
Event City THERMAL
Event State CALIFORNIA
Event Country --
Zipcode of the event site 92563
Event Date Year 1998
Event Date Month 12
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 Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1351 Pacific Standard Time
Direction of event from weather observation facility (degrees) 300
Weather Observation Facility ID TRM
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 15
Time Zone of the weather observation PST
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 22000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 25
Air Temperature at event time (in degrees celsius) 21
Dew Point at event time (in degress fahrenheit) -9
Wind Direction (degrees magnetic) 140
Variable Wind Indicator Unknown
Wind Speed (knots) 6
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
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 Fatal
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal 2
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 1980
NTSB Notification Source --
NTSB Notification Date Dec 27 1998 12:00AM
NTSB Notification Time 1030
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record May 19 2001 4:45AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N7776W
NTSB Number LAX99LA068
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire Unknown
Aircraft Explosion Unknown
Aircraft Manufacturer's Full Name Piper
Aircraft Model PA-28
Aircraft Series Identifier PA-28
Aircraft Serial Number 28-1780
Certified Max Gross Weight 2400
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 4
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Unknown
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed Unknown
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name ROBERT L CHATHAM
Aircraft Owner Street Address
Aircraft Owner City ESCONDIDO
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 92046
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
Owner has at least one certificate None
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 --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Personal
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code L77
Departure City CHIRIACO SUMMIT
Departure State CA
Departure Country
Departure Time 1333
Departure Time Zone PST
Destination Same as Local Flt --
Destination Airport Code RNM
Destination City RAMONA
Destination State CA
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record May 19 2001 4:08AM
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 --