GUYTON, GA, USA
N414MT
Cessna 414A
About 26 minutes after takeoff while at 21500 feet, the pilot requested a non existent route. Seven minutes later, the passenger stated the pilot was light headed and fading then he had passed out. The passenger had once held a student pilot certificate and about 5 years earlier she had accrued 73 hours of flight time in Cessna 150/152 aircraft. The air traffic controller, and other pilots on the radio frequency tried to assist the passenger. The passenger was advised to provide oxygen for herself and the pilot, but she was unable. The airplane climbed to 34,200 feet where the airplane departed controlled flight, recovered, then departed controlled flight several more times before beginning a nose low descent. Witnesses reported hearing the airplane orbiting several times while flying above a cloud layer then observed the airplane orbiting beneath the clouds. While in a descending right wing low attitude, the airplane impacted the ground and came to rest submerged in a pond. Examination of the flight controls, engines, and propellers revealed no evidence of preimpact failure or malfunction. A discrepancy with the regulating valve was noted. Two small holes were noted in the cabin door seal. The left wing pressurization duct had been replaced about 8 years earlier but the right wing pressurization duct, had not been replaced. The ducts are on-condition components. There was no preimpact failure or malfunction noted with the barometric pressure switch, the cabin altitude annunciator bulbs, the safety valve, solenoid valve, or differential pressure/cabin altitude gauge. Testing for carbonmonoxide for both was negative.
HISTORY OF FLIGHT On December 29, 1997, about 0845 eastern standard time, a Cessna 414A, N414MT, registered to the Valley Forge Manufacturing Corp., collided with terrain while descending near Guyton, Georgia. Visual meteorological conditions prevailed at the time and an IFR flight plan was filed for the 14 CFR Part 91 personal flight. The airplane was destroyed and the commercial-rated pilot and passenger were fatally injured. The flight originated about 0723 from the Orlando Executive Airport, Orlando, Florida. Review of the Air Traffic Control (ATC) communication tapes with the flight revealed that IFR clearance was received, the flight was cleared to taxi, and takeoff, then ATC tower transferred the flight to Orlando Approach Control, followed by Jacksonville Air Route Traffic Control Center, at 0734.39. At that time, a male voice (pilot) verified climbing to 12,000 feet and about 19 seconds later, the flight was cleared to flight level 190, which was acknowledged by the pilot. The flight was cleared to flight level 230 and at 0743.51, the flight was cleared by the controller to climb to flight level 250. The pilot acknowledged this and requested a routing change. The controller advised the pilot to standby, then about 5 minutes 12 seconds later, the controller advised the pilot to go ahead with his request. The pilot advised that after Savannah, the route would be Jet Route 191, Pulaski, as filed. The controller cleared the flight as requested then about 1 minute 25 seconds later, the controller advised the pilot that Jet Route 191 does not come out of Savannah, and there was no direct airway from Savannah to Pulaski. The pilot acknowledged this by stating that he would have to check his routing then at 0753.07, the flight was cleared direct Pulaksi (VORTAC) after Savannah. The pilot did not acknowledge that clearance; there were no further ATC communication with the pilot (male) voice. All subsequent communications are from the passenger (female) voice. At 0755.44, the passenger stated "we need help", followed by a mayday call 4 seconds later. Another mayday call transmitted at 0755.53, was acknowledged by the controller, followed by another mayday call at 0756.14. The controller again acknowledged this and at 0756.25, the passenger advised "in trouble the pilot is light headed and fading..." The controller acknowledged this then 11 seconds later, the passenger advised "the pilot is four one four mike tango is passing out do you hear me four one four mike tango pilot is passing out." The controller questioned the passenger whether she could fly the airplane but a flight crew member from a US AIRWAYS flight interjected and asked the passenger if oxygen was available to give to the pilot to which she responded, "I don't know how to get it." The US AIRWAYS flight crew questioned the altitude and the passenger responded, then advised "...The pilot is out I don't know what to do." The US AIRWAYS flight crew advised the passenger to put an oxygen mask on the pilot which the passenger acknowledged at 0757.55, by stating, "I'm looking for it I have to get up." There was no radio contact with the passenger from that point until 0801.46, when she stated that the flight was at flight level 268, and trying to level off. The controller advised her to push forward on the yoke and if oxygen was available, to put it on herself. The US AIRWAYS flight crew also advised her to provide oxygen to herself and to descend. The passenger advised that the pilot was still passed out and acknowledged that the flight needed to descend. The controller and flight crew of US AIRWAYS continued to advise the passenger that the flight needed to descend and at 0802.24, the passenger stated "...I'm pushing I am pushing on the uh wheel." At 0804.02, the passenger stated "trims appears to be going up and I don't understand I seriously don't know how to go down appears to still be climbing and tell me how to get down...." The US AIRWAYS flight crew then advised her to push very hard forward on the control column and to put oxygen on herself. At 0805.07, the passenger advised that the flight was out of control. The flight crew of US AIRWAYS advised the passenger to push a button on the yoke to release the autopilot. An absence of attempted contact by the passenger was noted between 0811.12, until 0827.38. At that time an open microphone with no voice was noted. The last evidence of attempted communication occurred about 0827.52. An F/A-18D (F18) that had departed the Beaufort Marine Corps Air Station at about 0810 for a training mission was vectored to fly near the airplane and at 0825.39, the controller advised the pilot of the F18 that the accident airplane was in a slow climb at flight level 336. The pilot of the F-18 reported visually acquiring the airplane at 0828.08, and at 0832.03, the F-18 pilot advised the controller that the airplane begins a descent right wing low and recovers, which occurs 2 more times. About 0834.40, the F18 pilot reports to the controller that the airplane was "...pointing straight down..." and about 0835.09, the F18 pilot observed the airplane enter clouds at flight level 200 while in a nose low attitude of about 80 degrees nose low. The F18 did not pursue the airplane for safety concerns. According to a statement from a controller at the Savannah Air Traffic Control Tower, the airplane was observed on radar in a rapid descent. The controller continued to track the airplane via radar and at 0840.44, the airplane was descending through 2,900 feet. Radar contact was lost at 500 feet on the 295 degree radial and 14 nautical miles from the Savannah VORTAC. Numerous witnesses near the crash reported hearing an airplane orbit two to three times above the clouds. The airplane descended beneath the base of the clouds and was seen by several witnesses to orbit two to three times. The airplane then began a right descending turn and impacted the ground first with the right wing tip. The airplane then rolled right, impacted obstacles on the ground, and came to rest in a small pond about 200 feet from the initial impact point. Review of the National Track Analysis Program (NTAP) track sort from the Jacksonville Air Route Traffic Control Center revealed that the airplane slowed to 78 knots ground speed with a nearly direct crosswind for the winds aloft at that altitude. The airplane then began a right descending turn, the ground speed increased, and the airplane returned to the north-northwesterly heading while climbing. The airplane continued climbing on about that same heading to flight level 342, and at 0832.14, the airplane began the second right descending turn. According to personnel from the Jacksonville ARTCC, the last radar return with mode C was at 0835.26. A copy of the NTAP track sort is an attachment to this report. OTHER DAMAGE Damage to a parked vehicle and the pond where the airplane crashed was noted. PERSONNEL INFORMATION The pilot had received recurrent flight training from January 13-15, 1997, at SIMCOM International, Inc., utilizing a fixed Cessna 421C simulator, with satisfactory results. The training consisted of 11.5 hours of ground instruction which included a total of 3 hours of briefs and debriefs over the 3 days. On the third day, 1.5 hours of ground instruction included training in environmental systems. The ground training was specific to a Cessna 414A airplane. A total of 6.0 hours of simulator instruction was accomplished over the course of five simulator sessions during the 3-day period. On the last simulator lesson of the third day, the loss of pressurization above 10,000 feet was accomplished. The simulator was capable of indicating this by the cabin altitude annunciator light, the cabin altitude gauge, and the cabin rate of climb. Oxygen in the simulator was not available to the pilot, though donning of the oxygen mask was simulated. Additional information pertaining to the pilot is contained on page 3 of the Factual Report-Aviation. The pilot's wife had received flight training and had accumulated a total of about 73 hours in Cessna 150/152 aircraft between February 17, 1991, and May 3, 1992. She was issued a student pilot medical certificate on June 12, 1991, and had completed a private pilot ground school on July 22, 1991. She did not receive any other pilot certificate. Review of records provided by the pilots daughter pertaining to the passenger revealed handwritten notes which indicate for a disabled pilot, to talk to ATC (Air Traffic Control). The notes also indicate that to descend while the autopilot is engaged, to press and hold the down switch, which is located on the autopilot mode controller. There is no mention in the notes to deactivate the autopilot by moving the autopilot on/off switch found on the autopilot mode controller to the "off" position. There also is no mention in the notes on the oxygen system. AIRCRAFT INFORMATION The airplane was modified in March 1997, which included the addition of winglets and spoilers, flap changes, and modifications to the engines which resulted in an increase of 25 horsepower per engine. The modifications allowed the increase in the airplane gross weight from 6,750 to 7,087 pounds, and a change in the aircraft performance. Review of the maintenance records revealed that the airplane was last inspected in accordance with an annual/100 hour inspection on November 19, 1997, at an aircraft total time of 3,866.4 hours. The facility that accomplished the inspection used the manufacturer's inspection checklist. Review of the manufacturer's service manual pertaining to the pressurization system revealed in part that the pressurization differential limiting check and the barometric pressure switch tests are required to be performed every 500 and 600 hours, respectively. All annual/100-hour inspections since October 1987, beginning with an airplane total time of 2,654.9 hours, were performed by the same facility. The maintenance records also indicate that during the annual inspection that was signed off on September 11, 1991, the left cabin pressure ducts were noted to be deteriorated. The ducts were removed and replaced. There was no record of the right pressure ducts being replaced. According to the current Director of Maintenance for the facility that had been inspecting the airplane since 1987, and who was the mechanic who found the deteriorated ducts during the inspection in 1991, there is no record that the barometric warning light test or the pressurization limiting tests having been accomplished in the last two years. Additionally, no documents exist to indicate whether the tests had or had not been performed while they had been inspecting the airplane. Also, there were no mechanics on staff that would be able to perform the flight checks. The airplane was equipped with a 114.9 cubic foot oxygen tank installed in the nose section of the airplane. The procedure to activate the flow of oxygen from the tank to the respective outlets required pulling the oxygen control located only on the pilot's lower instrument panel. The airplane was also equipped with a KAP 200 control system without the KCS 55A system, with the exception that a KC 290 mode controller was installed. The copilots control wheel did not have an autopilot disconnect switch. According to personnel from the autopilot manufacturer, that system does not contain roll or pitch rate monitors or vertical acceleration monitors which would be required to have an automatic autopilot disconnect feature when the aircraft slows to Vs or Vso with the autopilot engaged. By design the autopilot system will automatically disengage when there is external power failure, or by actuating the manual electric trim which is found on the pilot's control wheel. Additionally, according to the autopilot flight manual supplement for the installed autopilot system, when the autopilot system is engaged, manual application of a force to the pitch axis of the control wheel for a period of 3 seconds or more will result in the autotrim system operating in the direction to create a force opposing the pilot. The opposing mistrim force will continue to increase as long as the pilot applies a force to the control wheel and will ultimately overpower the autopilot. An air-gyro driven attitude indicator was installed in front of the copilot's seat. By design, pressurization air is supplied from each engine turbocharger through the sonic venturi, the heat exchanger, then into the cabin through check valves located in each wing root. The aircraft information manual indicates that adequate flow to maintain pressurization is provided by either engine at normal power settings. Additional information pertaining to the airplane is contained on page 2 of the Factual Report-Aviation. METEOROLOGICAL INFORMATION Information pertaining to the weather is contained on page 4 of the Factual Report-Aviation. Witnesses located about 1/4 mile from the crash site reported that it was drizzling at the time of the accident and a cloud layer of unknown height above the ground was noted. COMMUNICATIONS The Jacksonville, Florida, Air Route Traffic Control Center, was the last Air Traffic Control (ATC) facility in contact with the passenger. Transcripts of communications for all contacts with all ATC facilities, and Flight Service Station facilities are attachments to this report. WRECKAGE AND IMPACT INFORMATION The airplane crashed onto private property with the crash site located at North 32 degrees 15 minutes .49 and West 081 degrees 23 minutes.19. Examination of the site revealed that the main wreckage which consisted of the fuselage and partially separated left wing and right engine, was located in a pond. The fuselage was nearly submerged with the upper half of the vertical stabilizer and the top portion of the fuselage visible. A fuel sheen was noted on the water. The wreckage path from the initial point of impact with the ground to where the airplane came to rest was oriented on a magnetic heading of 054 degrees. The initial impact point on the ground was noted to be from the right wing with broken pieces from the navigation light lens and the right winglet adjacent to that location. A ground scar about 6 inches across continued from the initial impact point about 21 feet and ended at a circular depression made by the right engine. That depression was noted to be adjacent to a 36 feet wide pond which was found to contain the right propeller with all three propeller blades attached, and the right aileron. A ground scar from the left wing was located about 62 feet past the initial ground scar and to the left of the wreckage path with a propeller blade from the left propeller located on the centerline of the wreckage path about 82 feet from the initial impact site. Continuing forward from that point, the left winglet was located about 94 feet from the initial impact site and to the left of the wreckage path. A frame of a metal trailer which was located about 98 feet from the initial impact site, was contacted by the airplane and moved 11 inches forward. Burning of grass due to fire was noted from the forward edge of the pond forward about 63 feet. A vehicle which was located about 129 feet from the initial impact site, was found to have the oxygen bottle, the nose section of the airplane, and one of the other propeller blades from the left propeller adjacent to it. The rear glass of the vehicle was shattered, the trunk was slightly damaged, and the vehicle was found to be displaced forward from the long standing position where it had been parked. Slight ground scars were noted in the dirt beginning about 10 feet before the edge of the pond where the airplane came to rest about 200 feet from the initial impact point. Numerous components from the airplane were located along the wreckage path. The pond was drained then initial examination revealed that the fuselage consisted of a point near the pilot's seats, aft to the tailcone, including the horizontal and vertical stabilizers with their respective flight control surfaces. The left wing was noted to
Inadequate maintenance of the cabin pressurization system, which resulted in inadequate pressurization and incapacitation of the pilot due to the hypoxia. Also causal was the pilot's failure to adequately monitor the cabin pressurization system.
Source: NTSB Aviation Accident Database
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