Gulf of Mexico, GM, USA
N325JK
CIRRUS DESIGN CORP SR22T
The pilot was in cruise flight at 19,000 ft mean sea level when he became unresponsive to air traffic control. Military pilots dispatched to intercept the airplane reported that the pilot was seated upright with his head tilted back against his seat and was unresponsive. The airplane continued on its established course at 19,000 ft over the Gulf of Mexico, where radar contact was lost about 3.75 hours after the pilot's last communication with air traffic control. The engine likely lost total power due to fuel exhaustion and the airplane descended into the water. The airplane was equipped with a hypoxia recognition system which was designed to descend the airplane to a lower altitude in the event of pilot incapacitation. Given the altitude of the accident airplane, the system should have activated about 17 minutes after the pilot's last input or interaction with the system. Following the accident, the manufacturer identified a condition under which uncommanded inputs could be made to the airplane's avionics, which could interfere with the normal function of the hypoxia recognition and automated descent features; however, the reason for the accident airplane's continued flight at 19,000 ft could not be determined, as the airplane was not recovered. The last few transmissions by the pilot to air traffic control illustrated a degradation in communication consistent with incapacitation. Given this interaction with the pilot and the lack of response from the pilot when the airplane was intercepted, it is likely that the pilot became incapacitated due to hypoxic hypoxia.
HISTORY OF FLIGHTOn January 3, 2018, about 1806 central standard time, a Cirrus Design Corporation SR22T airplane, N325JK, was presumed destroyed when it went missing over the Gulf of Mexico. The pilot is presumed fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to a family member and Federal Aviation Administration (FAA) records, the pilot departed Wiley Post Airport (PWA), Oklahoma City, Oklahoma, about 1419, and was en route to Georgetown Municipal Airport (GTU), Georgetown, Texas. The pilot intended to fly to GTU in support of an animal rescue and return home later that evening. According to data provided by the FAA, about 15:09:53, the pilot contacted the Fort Worth Air Route Traffic Control Center (ZFW ARTCC) Ednas-low sector radar (EDN-LR) controller and advised that he was at Flight Level (FL) 190. At 15:10:06, the pilot was then advised by the controller that he was cleared direct to Gooch Springs (AGJ) and then direct to Georgetown; the pilot acknowledged. (see Figure 1.) Figure 1. Flight Track for N325JK About 15:15:47, the controller instructed the pilot to descend and maintain 15,000 ft msl and issued an altimeter setting of 30.30; the pilot acknowledged. At 15:16:57, the controller transmitted “and uh five juliet kilo it’s still not looking like you’re direct gooch springs there uh vector for gooch springs alpha golf juliet fly heading one nine zero”. The pilot replied “okay, vector for gooch springs um heading one niner zero for five juliet kilo.” At 15:17:09, the controller instructed the pilot to descend and maintain 13,000 ft. At 15:18:13, the controller repeated the instruction. At 15:18:18, the pilot replied “one three thirteen thousand five juliet kilo.” At 15:18:21, the controller confirmed with the pilot that he was the one that had responded to the descent instruction to 13,000 ft; the pilot replied in the affirmative. The controller then advised he had requested because he had not seen him start his descent; the pilot did not acknowledge. At 15:19:06, the controller queried “and three two five juliet kilo are you at flight level one nine zero or are you descending;” the pilot did not respond. The controller attempted to contact the pilot three more times with no response. A review of radar data showed that about 15:19:15, while the airplane remained at FL190, its heading changed from about 180 to 140. At 15:20:09, the controller transmitted “and five juliet kilo i see you identing can you hear me.” At 15:20:19, the controller transmitted “three two five juliet kilo ident observed i need you to fly heading two zero zero vector for your descent two zero zero acknowledge by ident;” the pilot did not respond. The controller continued multiple attempts over several minutes to contact the pilot with no response. At 15:33:52, the controller transmitted “november three two five juliet kilo fort worth center i can see your ident there please descend and maintain thirteen thousand three two five juliet kilo descend to one three thousand and if you have oxygen please switch it uh put it on right now;” the pilot did not respond. At about 15:34, N325JK entered Houston (ZHU) ARTCC airspace. Both controllers continued with multiple attempts to contact N325JK with no response. A review of radar data indicated that upon reaching FL190 at about 14:34:50, the aircraft then remained at about that altitude until radar contact was lost at 18:06:16. Multiple military airplanes were dispatched to intercept and observe the N325JK. The intercept pilots reported that the airplane was about 19,000 ft msl and at an airspeed that varied between 150 and 180 knots, on a south to southeast heading. The pilot was seated upright with his head tilted back. The intercept pilots stated that during their time following the airplane there was no change in the pilot’s position or the course of the airplane. There was no visible damage to the airplane and their attempts to gain the pilot’s attention were unsuccessful. They were unable to remain with the airplane and did not see the airplane descend into the water. PERSONNEL INFORMATIONThe pilot’s personal flight logbooks were not located. AIRCRAFT INFORMATIONThe airplane was equipped with two fuel tanks with a total fuel capacity of 94.5 gallons, 92 gallons of which was usable. Depending on the engine power setting, the airplane had an endurance between 3.8 and 5.5 hours. The airplane was equipped with a Cirrus Perspective+ integrated flight deck, which comprised of a primary flight display (PFD) and a multi-function display (MFD). All displays offer control for communication and navigation frequency selection. The Perspective+ system on the accident airplane was configured with an Emergency Descent Mode (EDM) function. This was a standard “feature” on all Perspective (0764.09 software and later) and all Perspective+ avionics equipped aircraft. According to the airplane records, the airplane had Garmin Software version 0764.32 (P/N: 006-B0764-32) which included the EDM function. Garmin Hypoxia Recognition with Automatic Descent Mode: The airplane was equipped with a hypoxia recognition system for the purpose of detecting pilot incapacitation because of hypoxia or other physical conditions by continuously monitoring the pilot’s interaction with the Garmin Perspective+ system. If the system determines that the pilot is not responding, the Emergency Descent Mode function is engaged. When activated, the system commands the airplane to descend to a lower altitude to provide the pilot and passengers an opportunity to recover from the effects of hypoxia. The system is only operative when the airplane’s altitude is above 14,900 ft (pressure altitude) and the Garmin automatic flight control system (AFCS) is engaged. Pilot interaction with the Perspective+ system is monitored by detecting key presses and turns of the knobs (audio panel and push-to-talk switch excluded). If a period of inactivity, time dependent on altitude, is detected, the hypoxia recognition system will initiate the Emergency Descent Mode. The accident airplane was at an altitude of about 19,000 ft which would result in an activation time of about 17 minutes. Upon activation of the Emergency Descent Mode, there are four sequential phases employed by the system; determining pilot alertness, descent to 14,000 ft MSL, and descent to 12,500 ft MSL. The Phases are: • Advisory Annunciation: When the system detects a sufficient period of inactivity, the Advisory Annunciation “ARE YOU ALERT?” is displayed. Selecting the ALERT Softkey will acknowledge the message and reset the system. Pressing any other softkey or turning a knob will also reset the system. • Caution Annunciation: When no pilot interaction is detected for an additional 60 seconds, the Caution Annunciation “HYPOXIA ALERT” is displayed. Again, selecting the ALERT Softkey will acknowledge the message and reset the system. Pressing any other softkey or turning a knob will also reset the system. • Warning Annunciation: When no pilot interaction is detected for an additional 60 seconds, the Warning Annunciation “AUTO DESCENT” is displayed in the Annunciation Window and “Automatic descent to 14,000FT in 60 seconds” is displayed in the Alerts Window. Once again, selecting the ALERT Softkey will acknowledge the message and reset the system. Pressing any other softkey or turning a knob will also reset the system. • Descent: When no interaction is detected for another 60 seconds, the system will automatically proceed with the descent. As the system prepares for descent, the Selected Altitude is set to 14,000 and the AFCS enters Indicated Airspeed (IAS) mode with the airspeed reference set to the maximum allowable airspeed setting for the specific aircraft model. AFCS lateral mode settings are not affected. As the descent begins, an “AUTO DESCENT” warning is displayed in the Annunciation Window. “AUTO DESCENT - Aircraft Descending to 14,000FT” is displayed in the Alerts Window. “EDM” is shown as an AFCS Status Annunciation indicating the system has entered Automatic Descent Mode. “EDM” A continuous repeating chime will be heard as long as Automatic Descent Mode is active. After the descent begins, Automatic Descent Mode can only be canceled by disconnecting the autopilot. As the airplane reaches 14,000 ft the system sets the AFCS to Altitude Hold mode. The AFCS will also remain in Automatic Descent Mode as indicated by “EDM” continuing to be displayed as an AFCS Status Annunciation. The system again begins monitoring for pilot interaction. If no pilot interaction is detected for four minutes, the system initiates the second descent. As the system prepares for this descent, the Selected Altitude is set to 12,500 ft msl and the AFCS again enters IAS mode with the airspeed reference set to the maximum allowable airspeed for the specific aircraft model. As the descent begins, an “AUTO DESCENT” warning is displayed in the Annunciation Window. “AUTO DESCENT - Aircraft Descending to 12,500FT” is displayed in the Alerts Window. “EDM” is shown as an AFCS Status Annunciation. Also, the continuous repeating chime is heard. As the airplane reaches 12,500 ft the system sets the AFCS to Altitude Hold mode. The AFCS will also remain in Automatic Descent Mode as indicated by “EDM” continuing to be displayed as an AFCS Status Annunciation as well as the continuing presence of the repeating chime. At this point, the AFCS must be disconnected to cancel Automatic Descent Mode. Cirrus Service Advisory: According to Cirrus Service Advisory SA19-09, dated April 26, 2019, Cirrus was made aware of a condition where the Dual Concentric Knob (DCK) on certain Garmin PFD and MFD units can exhibit uncommanded inputs, resulting in unintentional standby frequency changes, MFD page navigation, or similar behavior. In addition, these uncommanded inputs may interfere with the normal function of the Hypoxia Recognition System feature in the Garmin System Software. For the SR22T, the Service Advisory is effective for airplanes with the Perspective Avionics having software version v0764.09 (and later) or Perspective+ Avionics (all software versions). The accident airplane was equipped with Garmin Software version 0764.32 (P/N: 006-B0764-32). Cirrus provided the National Transportation Safety Board (NTSB) with a description of a software change that Garmin made to their Perspective+ system. According to Cirrus, Garmin revised the software responsible for resetting the hypoxia alert system. Before the change, the hypoxia alert would be reset when the system software detected when a dual concentric knob on the PFD or MFD had been turned (audio panel and push-to-talk switch excluded) or when a key was pressed. On December 6, 2019, Garmin released software update 02647.N4 for new Cirrus production aircraft manufactured after that date. With this software update, the alert will only be reset when the system detects that a key has been pressed.” Garmin has developed a software update “0764.38”, for aircraft delivered prior to December 6, 2019. The software is currently in testing with a release date to be determined. Oxygen System: The airplane was equipped with a Precise Flight, Inc. fixed oxygen system. This system was designed to provide supplemental oxygen for the pilot and passengers. The system consisted of a 77 cu ft bottle and a pressure regulator assembly located in the aft fuselage, a four or five place distribution manifold located in the headliner, a control panel located in the center console next to the flap switch, and up to five (5) flow devices consisting of either constant flow meters or demand regulators, with either a cannula or face mask for each user. For the Cirrus Perspective system, the MFD engine page displays the oxygen bottle pressure on oxygen pressure indicator. The Garmin display will also display a steady caution “OXYGEN QTY” when the bottle pressure is between 400 to 800 psig and will display a steady warning “OXYGEN QTY” when the bottle pressure is less than 400 psig. These alerts will only be displayed when the oxygen system is ON, or the aircraft is above 10,000 ft and the conditions exist for the warning. The Cirrus Perspective provides secondary annunciation on the PFD in the alerts window with audio alerts. The three types of alerts are Warning, Caution, and Advisory. The NTSB was provided a photograph that showed a partial image of the oxygen indicator on the accident airplane. The photograph, taken after the end of the flight before the accident flight, showed the oxygen indicator pointer between 500 and 600 psi. There were only two businesses at PWA that provided oxygen services; neither of these two businesses serviced the airplane with oxygen before the accident flight. AIRPORT INFORMATIONThe airplane was equipped with two fuel tanks with a total fuel capacity of 94.5 gallons, 92 gallons of which was usable. Depending on the engine power setting, the airplane had an endurance between 3.8 and 5.5 hours. The airplane was equipped with a Cirrus Perspective+ integrated flight deck, which comprised of a primary flight display (PFD) and a multi-function display (MFD). All displays offer control for communication and navigation frequency selection. The Perspective+ system on the accident airplane was configured with an Emergency Descent Mode (EDM) function. This was a standard “feature” on all Perspective (0764.09 software and later) and all Perspective+ avionics equipped aircraft. According to the airplane records, the airplane had Garmin Software version 0764.32 (P/N: 006-B0764-32) which included the EDM function. Garmin Hypoxia Recognition with Automatic Descent Mode: The airplane was equipped with a hypoxia recognition system for the purpose of detecting pilot incapacitation because of hypoxia or other physical conditions by continuously monitoring the pilot’s interaction with the Garmin Perspective+ system. If the system determines that the pilot is not responding, the Emergency Descent Mode function is engaged. When activated, the system commands the airplane to descend to a lower altitude to provide the pilot and passengers an opportunity to recover from the effects of hypoxia. The system is only operative when the airplane’s altitude is above 14,900 ft (pressure altitude) and the Garmin automatic flight control system (AFCS) is engaged. Pilot interaction with the Perspective+ system is monitored by detecting key presses and turns of the knobs (audio panel and push-to-talk switch excluded). If a period of inactivity, time dependent on altitude, is detected, the hypoxia recognition system will initiate the Emergency Descent Mode. The accident airplane was at an altitude of about 19,000 ft which would result in an activation time of about 17 minutes. Upon activation of the Emergency Descent Mode, there are four sequential phases employed by the system; determining pilot alertness, descent to 14,000 ft MSL, and descent to 12,500 ft MSL. The Phases are: • Advisory Annunciation: When the system detects a sufficient period of inactivity, the Advisory Annunciation “ARE YOU ALERT?” is displayed. Selecting the ALERT Softkey will acknowledge the message and reset the system. Pressing any other softkey or turning a knob will also reset the system. • Caution Annunciation: When no pilot interaction is detected for an additional 60 seconds, the Caution Annunciation “HYPOXIA ALERT” is displayed. Again, selecting the ALERT Softkey will acknowledge the message and reset the system. Pressing any other softkey or turning a knob will also reset the system. • Warning Annunciation: When no pilot interaction is detected for an additional 60 seconds, the Warning Annunciation “AUTO DESCENT” is displayed in the Annunciation Window and “Automatic descent to 14,000FT in 60 seconds” is displayed in the Alerts Window. Once again, selecting the ALERT Softkey will acknowledge the message and reset the system. Pressing any other softkey or turning a knob will also reset the system.
The pilot's incapacitation resulted in impact with the Gulf of Mexico. The reason the hypoxia recognition system did not descend the airplane as designed could not be determined as the airplane was not located.
Source: NTSB Aviation Accident Database
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