January 16, 2000 NTSB Incident Report on the Cessna 182N at Kerman, CA (LAX94LA184) |
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January 16, 2000
NTSB Identification: LAX94LA184.
The docket is stored in the (offline) NTSB
Imaging System.
Accident occurred APR-07-94 at KERMAN, CA
Aircraft: CESSNA 182N, registration: N9124G
Injuries: 1 Serious.
RECORDED RADAR & VOICE TAPES REVEALED THAT 15 MINUTES AFTER TAKEOFF, THE AIRCRAFT
BEGAN DEVIATING FROM HEADINGS, ALTITUDES, & ATC INSTRUCTIONS. THE FACILITIES WORKING
THE FLIGHT SAID THE AIRCRAFT'S COURSE OF FLIGHT WAS ERRATIC, WITH THE ERRATIC BEHAVIOR
BECOMING WORSE AS THE FLIGHT CONTINUED. THE PILOT SEEMED TO BE DISORIENTED. THE AIRCRAFT
DRIFTED SIGNIFICANTLY OFF ASSIGNED AIRWAYS & HEADINGS, & DID SEVERAL 360 & 180
DEGREE TURNS. THE PILOT SAID THAT AFTER REACHING CRUISE ALTITUDE, HE BEGAN TO EXPERIENCE
BLURRED VISION, HEADACHES, & NAUSEA. HE SAID HIS BREATHING BECAME LABORED, & THE
CONTROLS BECAME DIFFICULT TO MOVE. THE FLIGHTPATH OF THE AIRPLANE KEPT CHANGING DIRECTION
& ALTITUDE, & THE PILOT COULD NOT STAY AWAKE. MANY SMALL LEAKS WERE FOUND IN THE
EXHAUST SYSTEM, WITH GAS PATHWAYS FOUND INTO THE CABIN. HOSPITAL TESTS FOR ALCOHOL &
DRUGS WERE NEGATIVE. AN FAA FLIGHT SURGEON AT CAMI REVIEWED THE CASE & REPORTED THAT
THE SYMPTOMS WERE CONSISTENT WITH CARBON MONOXIDE POISONING. BLOOD DRAWN 11 HRS AFTER
ENTERING A HOSPITAL RETAINED 3% SATURATION WITH CARBON MONOXIDE.
Probable Cause
AN EXHAUST GAS LEAK, DUE TO INADEQUATE MAINTENANCE, WHICH RESULTED IN CARBON MONOXIDE
POISONING, INCAPACITION OF THE PILOT, AND LOSS OF AIRCRAFT CONTROL.
On April 7, 1994, at 2335 Pacific daylight time, a Cessna 182N, N9124G, collided with a
vineyard near Kerman, California, following an uncontrolled altitude deviation from
cruise. The aircraft was owned and operated by the pilot. Visual meteorological conditions
prevailed at the time and an IFR flight plan was filed. The aircraft incurred substantial
damage and the certificated private pilot, the sole occupant, sustained serious injuries.
The flight originated at Long Beach, California, on the day of the accident at 2113 hours
as a cross-country personal flight to Modesto, California.
During the investigation, Federal Aviation Administration (FAA) air-to-ground
communications tapes, recorded radar data, and statements from controllers from all air
traffic control facilities which worked the flight were reviewed. A radar flightpath chart
of the last 30 minutes of flight, and transcripts of the radio communications are attached
to this report.
The review revealed that within 15 minutes of takeoff, while being radar vectored by
Southern California terminal radar approach control (SOCAL TRACON), the aircraft began
deviating slightly from assigned headings, altitudes, and the ground controller's
instructions. As an example, while being radar vectored over the Los Angeles International
Airport, the pilot performed several 360-degree turns. In response to the controller's
inquiry, the pilot responded that he wanted to look at the city lights one last time
before he left. The facilities which worked the flight in successive order reported that
the aircraft was erratic in the course flown over an extended period of time, with the
erratic behavior becoming progressively worse as the flight continued. The pilot seemed to
have difficulty maintaining his orientation, drifted significantly off his assigned
airways and headings, and had done several 360- and 180-degree turns. In the latter stages
of the flight, the controllers reported that the pilot became more unresponsive to their
attempts at radio contact and air traffic control (ATC) instructions.
The pilot was interviewed several times by both FAA and National Transportation Safety
Board investigators. The pilot reported that in the initial part of his climb after
takeoff he turned on the cabin heat because he felt cold. He stated that he recalled doing
the 360-degree turns over Los Angeles International Airport because he wanted to take a
last look at the lights of the Los Angeles basin and he remembered the controller being
very irritated. The pilot said he did not recall very clearly the turns in the wrong
direction. He did recall eventually being handed off to Los Angeles air route traffice
control center (ARTCC) and reaching his assigned cruise altitude of 11,000 feet mean sea
level (msl).
Shortly after reaching cruise altitude, the pilot began to experience blurred vision,
headaches, and nausea. He stated that his breathing became very labored and he felt the
aircraft altitude was very difficult to control due to turbulence. He recalled being
handed off to Oakland ARTCC and asking for a visual flight rules (VFR) on top clearance
direct to Modesto at 6,500 feet. He stated that the controller was very difficult to
understand, but he eventually descended in accordance with the VFR on top direct
clearance.
After descending to what he believed was 6,500 feet, the flight controls became more
difficult to move and the flight path of the airplane kept changing direction and
altitude. He said that no matter how hard he tried to stay awake he would drift off, then
find himself in what he thought at the time were turns. He remembered thinking that he had
to get control of the aircraft, but he could not make his arms and hands move. He said he
does not remember anything after that until waking up in the hospital emergency room.
WRECKAGE EXAMINATION
The aircraft wreckage was examined in detail both on site and after recovery by FAA
airworthiness inspectors from the Fresno, California, Flight Standards District Office.
The engine compartment, fuselage, and cabin were specifically examined for evidence of
exhaust gas intrusion into the occupiable areas of the aircraft. The inspector's report is
attached.
The exhaust manifold and tubes were examined. The connecting clamp for the Nos. 1 and 3
exhaust tubes exhibited gas blow-by stains. A pin hole with exhaust stains was observed on
the cylinder No. 6 tube at a point about 5 inches from the flange. Gas blow-by stains were
also evident on the cylinder No. 6 tube at the lower manifold clamp.
The heat exchanger inner liner was found to be burned out. The muff clamps exhibited
evidence of leakage.
The heat box and mixer duct had exhaust stains on the valve face and around the hot air
exit. Small holes were noted in the heater air duct material.
The nose wheel steering boots had holes worn in the material. Exhaust stains were
observed on the aircraft belly skin, principally on the right side of the fuselage.
Inspection panels in the area did not appear to seal adequately and exhibited exhaust-type
stains in and around the internal sides. The strobe light assembly was improperly sealed,
with evidence of exhaust stains noted internally.
MEDICAL AND TOXICOLOGICAL INFORMATION
The pilot sustained serious injuries in the accident and was transported by ambulance
to Valley Medical Center in Fresno, California, for admission and treatment of his
injuries. While a blood test for alcohol was not performed, the admitting emergency room
physician reported that he did not detect the odor of alcohol and the patient did not
exhibit symptoms which would cause him to suspect alcohol. The hospital blood screen for
drug substances was negative.
At the request of the National Transportation Safety Board, a blood test for carbon
monoxide was performed approximately 11 hours after admission to the hospital. The blood
saturation was found to be 3 percent; however, hospital records noted that the pilot had
been under continuous oxygen therapy since admission.
An FAA flight surgeon in AAM-611 at the Civil Aeromedical Institute (CAMI) was
contacted by telephone. The doctor verbally reported that carbon monoxide (CO) poisoning
has a fairly rapid onset and has the following typical symptoms for the stated CO levels:
at 20 percent, nausea and blurred vision; at 30 percent, headache and some impairment of
motor functions; at 40 percent, near unconsciousness to death. The flight surgeon also
stated that CO has a half-life of 45 minutes under oxygen therapy (1/2 of the CO blood
saturation is eliminated) and that 5 half-lives typically yields a 98 percent reduction in
the CO level.
The flight surgeon reviewed the audio tapes of the recorded air- to-ground
communications between the pilot and the involved air traffic facilities. The doctor
reported that CO poisoning is a plausible and likely occurrence in this instance.
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