Crash of a Canadair CL-601 Challenger off Aruba: 3 killed

Date & Time: Jan 29, 2015
Type of aircraft:
Operator:
Registration:
N214FW
Flight Phase:
Flight Type:
Survivors:
No
MSN:
3008
YOM:
1983
Crew on board:
3
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
3
Circumstances:
The aircraft left an airfield located somewhere in the State of Apure, Venezuela, apparently bound for the US with three people on board. While flying north of Punto Fijo, above the sea, the crew was contacted by ATC but failed to respond. Convinced this was an illegal flight, the Venezuelan Authorities decided to send a fighter to intercept the Challenger that was shot down. Out of control, it dove into the Caribbean Sea and crashed off the coast of Aruba Island. All three occupants were killed and on site, more than 400 boxes containing cocaine were found.
Probable cause:
Shot down by the pilot of a Venezuelan Air Force fighter.

Crash of a Pacific Aerospace PAC 750XL in Taupo Lake

Date & Time: Jan 7, 2015 at 1216 LT
Operator:
Registration:
ZK-SDT
Flight Phase:
Survivors:
Yes
Schedule:
Taupo - Taupo
MSN:
122
YOM:
2005
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
12
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
588
Captain / Total hours on type:
14.00
Circumstances:
On 7 January 2015 a Pacific Aerospace Limited 750XL aeroplane was being used for tandem parachuting (or ‘skydiving’) operations at Taupō aerodrome. During the climb on the fourth flight of the day, the Pratt & Whitney Canada PT6A-34 engine failed suddenly. The 12 parachutists and the pilot baled out of the aeroplane and landed without serious injury. The aeroplane crashed into Lake Taupō and was destroyed.
Probable cause:
The following findings were identified:
- The first compressor turbine blade failed after a fatigue crack, which had begun at the trailing edge, propagated towards the leading edge. The blade finally fractured in tensile overload. The separated blade fragment caused other blades to fracture and the engine to stop.
- The fatigue crack in the trailing edge of the blade was likely initiated by the trailing edge radius having been below the specification for a new blade.
- The P&WC Repair Requirement Document 725009-SRR-001, at the time the blades were overhauled, had generic requirements for trailing edge thickness inspections but did not specify a minimum measurement for the trailing edge radius.
- The higher engine power settings used by the operator since August 2014 were within the flight manual limits. Therefore it was unlikely that the operator’s engine handling policy contributed to the engine failure.
- The operator had maintained the engine in accordance with an approved, alternative maintenance programme, but the registration of the engine into that programme had not been completed. The administrative oversight did not affect the reliability of the engine or contribute to the blade failure.
- It was likely that the maintenance provider had not followed fully the engine manufacturer’s recommended procedure for inspecting the compressor turbine blades. It could not be determined whether the crack might have been present, and potentially detectable, at the most recent borescope inspection.
- The operator had not equipped its pilots with flotation devices to cover the possibility of a ditching or an emergency bale-out over or near water.
- The pilot had demonstrated that he was competent and he had the required ratings. However, it was likely that the operator’s training of the pilot in emergency procedures was inadequate. This contributed to the pilot making a hasty exit from the aeroplane that jeopardized others.
Final Report:

Crash of an Airbus A320-216 into the Java Sea: 162 killed

Date & Time: Dec 28, 2014 at 0618 LT
Type of aircraft:
Operator:
Registration:
PK-AXC
Flight Phase:
Survivors:
No
Schedule:
Surabaya – Singapore
MSN:
3648
YOM:
2008
Flight number:
QZ8501
Country:
Region:
Crew on board:
6
Crew fatalities:
Pax on board:
156
Pax fatalities:
Other fatalities:
Total fatalities:
162
Captain / Total flying hours:
20537
Captain / Total hours on type:
4687.00
Copilot / Total flying hours:
2247
Copilot / Total hours on type:
1367
Aircraft flight hours:
23039
Aircraft flight cycles:
13610
Circumstances:
The aircraft left Surabaya-Juanda Airport at 0535LT and climbed to its assigned altitude of FL320 that he reached 19 minutes later. The crew contacted ATC to obtain the authorization to climb to FL380 and to divert to 310° due to bad weather conditions. At 0617, the radio contact was lost with the crew and a minute later, the transponder stopped when the aircraft disappeared from the radar screen. At this time, the aircraft was flying at the altitude of 36,300 feet and its speed was decreasing to 353 knots. It is believed the aircraft crashed some 80 nautical miles southeast off the Pulau Belitung Island, some 200 km from the Singapore Control Area. The Indonesian Company confirmed there were 156 Indonesian Citizens on board, three South Korean, one Malaysian, one Singapore and one French (the copilot) as well. At the time of the accident, the weather conditions were marginal with storm activity, rain falls and turbulence in the area between Pulau Belitung and Kalimantan. First debris were spotted by the Indonesian Navy some 48 hours later, about 150 NM east-south-east off the Pulau Belitung Island. About forty dead bodies were found up to December 30. The tail was recovered on January 10, 2015 and the black boxes were localized a day later. On January 12 and 13 respectively, the DFDR and the CVR were out of water and sent to Jakarta for analysis and investigations.
Probable cause:
The cracking of a solder joint of both channel A and B resulted in loss of electrical continuity and led to RTLU (rudder travel limiter unit) failure.
The existing maintenance data analysis led to unresolved repetitive faults occurring with shorter intervals. The same fault occurred 4 times during the flight.
The flight crew action to the first 3 faults in accordance with the ECAM messages. Following the fourth fault, the FDR recorded different signatures that were similar to the FAC CB‟s being reset resulting in electrical interruption to the FAC‟s.
The electrical interruption to the FAC caused the autopilot to disengage and the flight control logic to change from Normal Law to Alternate Law, the rudder deflecting 2° to the left resulting the aircraft rolling up to 54° angle of bank.
Subsequent flight crew action leading to inability to control the aircraft in the Alternate Law resulted in the aircraft departing from the normal flight envelope and entering prolonged stall condition that was beyond the capability of the flight crew to recover.
Final Report:

Crash of a Cessna 208B Grand Caravan off Belize City

Date & Time: Dec 4, 2014 at 1420 LT
Type of aircraft:
Operator:
Registration:
V3-HHU
Survivors:
Yes
Schedule:
San Pedro – Belize City
MSN:
208B-2025
YOM:
2008
Flight number:
9N281
Country:
Crew on board:
1
Crew fatalities:
Pax on board:
5
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
After landing at Belize City-Sir Barry Bowen Municipal Airport in marginal weather conditions, the single engine aircraft was unable to stop within the remaining distance. It overran, lost its right main gear, plunged into the sea and came to rest in shallow water. All six occupants were rescued and the aircraft was damaged beyond repair.

Crash of a Piper PA-31-350 Navajo Chieftain off Nassau: 1 killed

Date & Time: Dec 2, 2014 at 0845 LT
Operator:
Registration:
C6-REV
Flight Phase:
Survivors:
Yes
Schedule:
Governor’s Harbour – Nassau
MSN:
31-7652062
YOM:
1976
Flight number:
302
Country:
Crew on board:
1
Crew fatalities:
Pax on board:
10
Pax fatalities:
Other fatalities:
Total fatalities:
1
Captain / Total flying hours:
7650
Aircraft flight hours:
11744
Circumstances:
On Tuesday December 2nd, 2014 at approximately 8:45 am (1345Z) a Ferg’s Air Limited, Piper PA-31-350 Navajo aircraft, registration C6-REV, operated as Southern Air Limited Flight 302, ditched in waters approximately 6nm from shore in the southwestern district of New Providence. The flight originated at Governor’s Harbour, Eleuthera (MYEM) with 10+1 persons on board at approximately 8:15 am in Visual Meteorological Conditions (VMC). At around 8:30am, the aircraft 15 nautical miles east of Lynden Pindling International Airport at 4,500 feet contacted Nassau Air Traffic Control Tower. The aircraft was instructed that runway 09 was in use and they can expect a landing on that runway. Upon final approach to runway 09, with the landing gears selected to the “EXTEND” position, only the nose and right main landing gear lights indicated the “down and locked” position. The left main landing gear light did not illuminate to indicate the “down and locked” position, so the landing was aborted and the pilot requested to go around so he could recycle and troubleshoot the landing gear issue. The pilot made a left turn, flew over the north western shoreline and recycled the landing gears a few times and also tried the emergency hand pump in an attempt to extend the gear. Despite all efforts, the left main landing gear light still did not illuminate to indicated the gear was in the safe “down and locked” position. At this time the aircraft was allowed to fly by the tower so that the controller may make a visual check of the landing gears to see if they were in the extended position. The controller advised the pilot that all gears “appeared to be extended”. Once again the pilot proceeded outbound to make another attempt for landing. For this approach the pilot made a right turn over the southwestern shoreline and proceeded downwind to runway 09. While on the downwind to runway 09 the pilot stated he began to experience problems with the right engine. The engine eventually stopped and all attempts to restart were unsuccessful. As a result of single engine operation, level flight could not be maintained even after retracting the gears and cleaning up the airplane. The decision was made by the pilot to ditch in the water vs. attempting to make the airport where numerous trees and obstacles would make the landing more difficult if the runway could not be made. After touching down on the water the most of the occupants were able to evacuate the aircraft through the normal and emergency exits before the aircraft sank into the ocean. One passenger died during the process. Witness stated that “the plane skipped across the water three times before rotating and hitting with a severe impact. The port (left) tail section received the bulk of the impact as did the port side of the plane.” Eye witness further stated that the passenger that died and “luggage from the baggage compartment were ejected from the rear of the plane on the port side.” “Multiple passengers could not swim or were extremely limited in their ability to swim.” Despite the plane having the full complement of survival equipment (life vests), only two were taken out of the aircraft. Passengers were holding on to bags and other debris that floated out of the aircraft as it submerged. Passengers helped each other until rescuers arrived to assist. Estimates from eye witness were that “the entire plane disappeared under water from 30 to 60 seconds after impact.” The depth where the aircraft came to rest on the water was reported as in excess of 6,500 feet. Once the aircraft settled, it submerged and was not able to be recovered. Safety concerns raised by eye witness could not be confirmed as the plane was never recovered.
Probable cause:
The AAIPU determines that the probable causes of this accident as:
- Engine failure and the inability of the aircraft to maintain a safe altitude.
Contributing Factors includes:
- Failure of the left main landing gear.
The following findings were identified:
1. Weather was not a factor in the accident.
2. Air Traffic Services were proper and did not contribute to the cause of the accident.
3. The pilot was properly certified, trained and qualified for the flight.
4. The loss of power on the right engine resulted in the aircraft inability to maintain a safe altitude.
5. The Police and other emergency services response were timely and effective.
6. The depth of the water where the aircraft came to rest made it impossible for the aircraft to be recovered.
7. The aircraft was properly maintained in accordance with Bahamas and United States regulations and maintenance practices.
Final Report:

Crash of a Cessna 208B Grand Caravan in Great Slave Lake

Date & Time: Nov 20, 2014 at 0721 LT
Type of aircraft:
Operator:
Registration:
C-FKAY
Flight Phase:
Survivors:
Yes
Schedule:
Yellowknife – Fort Simpson
MSN:
208B-0470
YOM:
1995
Flight number:
8T223
Country:
Crew on board:
1
Crew fatalities:
Pax on board:
5
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
3500
Captain / Total hours on type:
1800.00
Aircraft flight hours:
25637
Circumstances:
The Air Tindi Ltd. Cessna 208B Caravan departed Yellowknife Airport, Northwest Territories, on 20 November 2014 at 0642 Mountain Standard Time under instrument flight rules as Discovery Air flight DA223 to Fort Simpson, Northwest Territories. The flight had been rescheduled from the previous night because of freezing drizzle at Fort Simpson. During the climb to 8000 feet above sea level, DA223 encountered icing conditions that necessitated a return to Yellowknife. On the return to Yellowknife, DA223 was unable to maintain altitude. At 0721, flying in darkness approximately 18 nautical miles west of Yellowknife, it contacted the frozen surface of the North Arm of Great Slave Lake. The aircraft sustained substantial damage when it struck a rock outcropping, but there were no injuries to the pilot or to the 5 passengers. The pilot established communication with Air Tindi via satellite phone, and the pilot and passengers were recovered approximately 4 hours after the landing. The emergency locator transmitter did not activate during the landing, but was activated manually by the pilot.
Probable cause:
Findings as to causes and contributing factors:
1. Not using all enroute information led the pilot to underestimate the severity and duration of the icing conditions that would be encountered.
2. Inadequate awareness of aircraft limitations in icing conditions and incomplete weight-and-balance calculations led to the aircraft being dispatched in an overweight state for the forecast icing conditions. The aircraft centre of gravity was not within limits, and this led to a condition that increased stall speed and reduced aircraft climb performance.
3. The pilot’s expectation that the flight was being undertaken at altitudes where it should have been possible to avoid icing or to move quickly to an altitude without icing conditions led to his decision to continue operation of the aircraft in icing conditions that exceeded the aircraft’s performance capabilities.
4. The severity of the icing conditions encountered and the duration of the exposure resulted in reductions in aerodynamic performance, making it impossible to prevent descent of the aircraft.
5. The inability to arrest descent of the aircraft resulted in the forced landing on the surface of Great Slave Lake and the collision with terrain.
6. The Type C pilot self-dispatch system employed by Air Tindi did not have quality assurance oversight or adequate support systems. This contributed to the aircraft being dispatched in conditions not suitable for safe flight.
Findings as to risk:
1. If passenger briefings on cabin door operations are ineffective, there is a risk of passenger egress in an accident being compromised, affecting survivability.
2. If survival equipment is stowed in a location that may be inaccessible following an accident, such as the belly pod, there is a risk of survival being compromised if search and rescue is delayed.
Other findings:
1. The aircraft was under control and in a level attitude when it contacted the ice. This minimized structural damage and increased survivability for the aircraft’s occupants.
2. The survival skills of the crew and passengers were indispensable in a situation in which access to the survival equipment on the aircraft was limited.
Final Report:

Crash of a Short 360-200 off Sint Maarten: 2 killed

Date & Time: Oct 29, 2014 at 1840 LT
Type of aircraft:
Operator:
Registration:
N380MQ
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Sint Maarten - San Juan
MSN:
3702
YOM:
1986
Flight number:
SKZ7101
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
5318
Captain / Total hours on type:
361.00
Copilot / Total flying hours:
1040
Copilot / Total hours on type:
510
Aircraft flight hours:
25061
Aircraft flight cycles:
32824
Circumstances:
On October 29, 2014, at about 1840 Atlantic Standard Time, a Shorts SD3-60, United States registered N380MQ was destroyed when it crashed into the sea shortly after takeoff from Runway 28 at Princess Juliana International Airport, Sint Maarten, Dutch Antilles, Kingdom of the Netherlands. The two crewmembers on board sustained fatal injuries. The aircraft was operated by SkyWay Enterprises Inc. on a scheduled FedEx contract cargo flight to Luis Munoz Marin International Airport, San Juan, Puerto Rico. At 1839 local, Juliana Tower cleared the aircraft for takeoff Runway 28 - maintain heading 230 until passing 4000 feet. At 1840 local, Tower observed the aircraft descending visually and the radar target and data block disappeared. There were no distress calls. Night conditions and rain prevailed at the time of the accident. Coast Guard search crews discovered aircraft debris close to the shoreline about 1 ½ hours later. The Sint Maarten Civil Aviation Authority initiated an investigation in accordance with ICAO Annex 13. Local investigation authority personnel were joined by Accredited Representatives and advisors from the following states: the USA (NTSB/FAA), United Kingdom (AAIB and Shorts Brothers PLC), and Canada (TSB, TC, PWC). Organization of the investigation included the following groups: Operations, Accident Site and Wreckage, Powerplants, Aircraft Maintenance, Air Traffic Services, Meteorology, and GPS Study. The operator made available personnel for interviews but deferred to participate in the groups. Flight recorders were not installed nor required on this cargo configured aircraft. The original FDR and CVR were removed following conversion to cargo only operations. A handheld GPS recovered from submerged wreckage was successfully downloaded. Data revealed the aircraft past the departure runway threshold on takeoff and attained a maximum GPS recorded altitude of 433 feet at 119 knots groundspeed at 18:39:30. The two remaining data points were over the sea and recorded decreasing altitude and increasing airspeed. The wreckage was recovered from the sea and examined by technical experts. Assessment of the evidence concluded there were no airframe or engine malfunctions that would have affected the airworthiness of the aircraft. The experts concluded that the aircraft struck the sea while under normal engine operation. Operations and human performance investigators evaluated the evidence and analyzed extensive interviews. The investigation concluded that the aircraft departed from the expected flight path in an unusual attitude. The pilot flying most likely experienced a somatographic illusion as a result of a stressful takeoff and acceleration from flap retraction. The pilot’s reaction to pitch down while initiating a required heading change led to an extreme unusual attitude. Circumstances indicate the pilot monitoring did not perceive/respond/intervene to correct the flight path and recover from the unusual attitude. The aircraft exceeded the normal maneuvering parameters, the crew experienced a loss of control, and lacking adequate altitude for recovery, the aircraft crashed into the sea.
Probable cause:
The investigation believes the PF experienced a loss of control while initiating a turn to the required departure heading after take-off. Flap retraction and its associated acceleration combined to set in motion a somatogravic illusion for the PF. The PF’s reaction to pitch down while initiating a turn most likely led to an extreme unusual attitude and the subsequent crash. PM awareness to the imminent loss of control and any attempt to intervene could not be determined. Evidence show that Crew resource management (CRM) performance was insufficient to avoid the crash. Contributing factors to the loss of control were environmental conditions including departure from an unfamiliar runway with loss of visual references (black hole), night and rain with gusting winds.
Final Report:

Crash of a Cessna 208 Caravan I in the Laguna de Tres Palos

Date & Time: Oct 24, 2014 at 1600 LT
Type of aircraft:
Operator:
Registration:
XA-WET
Flight Phase:
Flight Type:
Survivors:
Yes
Schedule:
Laguna de Tres Palos - Acapulco
MSN:
208-0294
YOM:
1998
Country:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
5240
Captain / Total hours on type:
201.00
Copilot / Total flying hours:
23837
Aircraft flight hours:
1760
Aircraft flight cycles:
1105
Circumstances:
The crew departed Laguna de Tres Palos on a positioning flight to the Acapulco-General Juan N. Álvarez International Airport. During the takeoff procedure, the seaplane started to oscillate from left to right. At a speed of about 45 knots, the crew abandoned the takeoff procedure when the aircraft nosed down, plunged into water and came to rest, inverted and submerged. Both pilots evacuated safely while the aircraft was damaged beyond repair.
Probable cause:
Loss of control of the aircraft during a takeoff run from a watery surface due to cross winds.
Final Report:

Crash of a Rockwell 690C Jetprop 840 off Los Roques

Date & Time: Oct 10, 2014 at 1000 LT
Operator:
Registration:
YV1315
Flight Phase:
Flight Type:
Survivors:
Yes
Schedule:
Los Roques - Charallave
MSN:
690-11618
YOM:
1980
Country:
Crew on board:
2
Crew fatalities:
Pax on board:
5
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
The twin engine aircraft was performing a private flight from the island of Los Roques to Charallave-Óscar Machado Zuloaga Airport. Shortly after take off, while in initial climb, the aircraft went out of control and crashed in a lagoon, few metres off shore. All seven occupants evacuated and were slightly injured while the aircraft broke in two in shallow water.

Crash of a Socata TBM-900 off Port Antonio: 2 killed

Date & Time: Sep 5, 2014 at 1410 LT
Type of aircraft:
Operator:
Registration:
N900KN
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Rochester - Naples
MSN:
1003
YOM:
2014
Country:
Crew on board:
1
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
7100
Captain / Total hours on type:
4190.00
Aircraft flight hours:
97
Circumstances:
The commercial pilot and his wife departed New York in their turboprop airplane on a crosscountry flight to Florida. About 1 hour 40 minutes into the flight and while cruising at flight level (FL) 280, the pilot notified air traffic control (ATC) of an abnormal indication in the airplane and requested a descent to FL180. The responding controller instructed the pilot to descend to FL250 and turn left 30°, and the pilot acknowledged and complied with the instruction; he then again requested a lower altitude. Although the pilot declined emergency handling and did not specify the nature of the problem, the controller independently determined that the flight had encountered a pressurization issue and immediately coordinated with another ATC facility to clear nearby traffic. The controller then issued instructions to the pilot to descend to FL200 and change course; however, the pilot did not comply with the assignments despite acknowledging the instructions multiple times. The pilot's failure to comply with the controller's instructions, his long microphone pauses after concluding a statement over the radio, and his confusion were consistent with cognitive impairment due to hypoxia. Further, the pilot's transmissions to ATC indicated impairment within 2 minutes 30 seconds of reporting the abnormal indication, which is consistent with the Federal Aviation Administration's published time of useful consciousness/effective performance time ranges for the onset of hypoxia. Military airplanes were dispatched about 30 minutes after the pilot's final transmission to ATC to intercept and examine the airplane. The pilots of the military airplanes reported that the airplane appeared to be flying normally at FL250, that both occupants appeared to be asleep or unconscious, and that neither occupant was wearing an oxygen mask. Photographs taken from one of the military airplanes revealed that the airplane's emergency exit door was recessed into the fuselage frame, consistent with a depressurized cabin. The military airplanes escorted the airplane as it continued on a constant course and altitude until it approached Cuban airspace, at which point they discontinued their escort. Radar data indicated that the airplane continued on the same flight track until about 5 hours 48 minutes after takeoff, when it descended to impact in the Caribbean Sea north of Jamaica. The flight's duration was consistent with a departure with full fuel and normal cruise endurance. Some of the wreckage, including fuselage and engine components, was recovered from the ocean floor about 4 months after the accident. Data recovered from nonvolatile memory in the airplane's global air system controller (GASC) indicated that several fault codes associated with the cabin pressurization system were registered during the flight. These faults indicated that the overheat thermal switch (OTSW), which was associated with overheat protection, had activated, which resulted in a shutdown of the engine bleed air supply to the cabin pressurization system. Without a bleed air supply to maintain selected cabin pressure, the cabin altitude would have increased to the altitude of the outside environment over a period of about 4 minutes. The faults recorded by the GASC's nonvolatile memory and associated system alerts/warnings would have been displayed to the pilot, both as discrete system anomaly messages on the crew alerting system (CAS) and as master warning and/or master caution annunciations. A witness report indicated that the pilot was known to routinely monitor cabin altitude while flying in the airplane and in his previous pressurized airplanes. Based on his instrument scanning practices and the airplane's aural warning system, he likely would have observed any CAS message at or near its onset. Thus, the CAS messages and the associated alerts were likely the precipitating event for the pilot's call to ATC requesting a lower altitude. The pilot was likely not familiar with the physiological effects of hypoxia because he had not recently been in an altitude chamber for training, but he should have been familiar with the airplane's pressurization system emergency and oxygen mask donning procedures because he had recently attended a transition course for the accident airplane make and model that covered these procedures. However, the pressurization system training segment of the 5-day transition course comprised only about 90 minutes of about 36 total hours of training, and it is unknown if the pilot would have retained enough information to recognize the significance of the CAS messages as they appeared during the accident flight, much less recall the corresponding emergency procedures from memory. Coupled with the pilot's reported diligence in using checklists, this suggests that he would have attempted a physical review of the emergency procedures outlined in the Pilot's Operating Handbook (POH). A review of the 656-page POH for the airplane found that only one of the four emergency checklist procedures that corresponded to pressurization system-related CAS messages included a step to don an oxygen mask, and it was only a suggestion, not a mandatory step. The combined lack of emergency guidance to immediately don an oxygen mask and the rapid increase in the cabin altitude significantly increased the risk of hypoxia, a condition resistant to self-diagnosis, especially for a person who has not recently experienced its effects in a controlled environment such as an altitude chamber. Additionally, once the pilot reported the problem indication to ATC, he requested a descent to FL180 instead of 10,000 ft as prescribed by the POH. In a second transmission, he accepted FL250 and declined priority handling. These two separate errors were either early signs of cognitive dysfunction due to hypoxia or indications that the pilot did not interpret the CAS messages as a matter related to the pressurization system. Although the cabin bleed-down rate was 4 minutes, the pilot showed evidence of deteriorating cognitive abilities about 2 minutes 30 seconds after he initially reported the problem to ATC. Ultimately, the pilot had less than 4 minutes to detect the pressurization system failure CAS messages, report the problem to ATC, locate the proper procedures in a voluminous POH, and complete each procedure, all while suffering from an insidious and mentally impairing condition that decreased his cognitive performance over time. Following the accident, the airplane manufacturer revised the emergency procedures for newly manufactured airplanes to require flight crews to don their oxygen masks as the first checklist item in each of the relevant emergency checklists. Further, the manufacturer has stated that it plans to issue the same revisions for previous models in 2017. The airplane manufacturer previously documented numerous OTSW replacements that occurred between 2008 and after the date of the accident. Many of these units were removed after the GASC systems in their respective airplanes generated fault codes that showed an overheat of the bleed air system. Each of the OTSWs that were tested at the manufacturer's facility showed results that were consistent with normal operating units. Additionally, the OTSW from the accident airplane passed several of the manufacturer's functional tests despite the presence of internal corrosion from sea water. Further investigation determined that the pressurization system design forced the GASC to unnecessarily discontinue the flow of bleed air into the cabin if the bleed air temperature exceeded an initial threshold and did not subsequently fall below a secondary threshold within 30 seconds. According to the airplane manufacturer, the purpose of this design was to protect the structural integrity of the airplane, the system, and the passengers in case of overheat detection. As a result of this accident and the ensuing investigation, the manufacturer made changes to the programming of the GASC and to the airplane's wiring that are designed to reduce the potential for the GASC to shut off the flow of bleed air into the cabin and to maximize the bleed availability. Contrary to its normal position for flight, the cockpit oxygen switch was found in the "off" position, which prevents oxygen from flowing to the oxygen masks. A witness's description of the pilot's before starting engine procedure during a previous flight showed that he may not have precisely complied with the published procedure for turning on the oxygen switch and testing the oxygen masks. However, as the pilot reportedly was diligent in completing preflight inspections and checklists, the investigation could not determine why the cockpit oxygen switch was turned off. Further, because the oxygen masks were not observed on either occupant, the position of the oxygen switch would not have made a difference in this accident.
Probable cause:
The design of the cabin pressurization system, which made it prone to unnecessary shutdown, combined with a checklist design that prioritized troubleshooting over ensuring that the pilot was sufficiently protected from hypoxia. This resulted in a loss of cabin pressure that rendered the pilot and passenger unconscious during cruise flight and eventually led to an in-flight loss of power due to fuel exhaustion over the open ocean.
Final Report: