HISTORY OF FLIGHTOn April 11, 2014, at 1653 eastern daylight time, a Piper PA-32RT-300T, N39965, was destroyed when it impacted trees and terrain near Hugheston, West Virginia. The commercial pilot and passenger were fatally injured. Instrument meteorological conditions prevailed along the route of flight, and an instrument flight rules flight plan was filed. The personal flight departed Akron Fulton International Airport (AKR), Akron, Ohio, about 1513, and was destined for Spartanburg Downtown Memorial Airport (SPA), Spartanburg, South Carolina. The airplane was registered to C.W. Air, LLC, and operated under the provisions of Title 14 Code of Federal Regulations Part 91. Air traffic control (ATC) voice communication and radar data provided by the Federal Aviation Administration (FAA) indicated that after departure, the pilot established radio contact with the Indianapolis Air Route Traffic Control Center and climbed the airplane to its cruise altitude of 12,000 feet on a direct course to SPA. About 1604, the controller advised the pilot of an area of moderate-to-extreme precipitation located at the airplane's 1- to 2-o'clock position about 45 miles ahead, and instructed the pilot to advise which way he wanted to deviate once he neared the area. The pilot replied that he would advise, and stated, "I see it here on this radar too." About 1612, the pilot contacted ATC and stated that, based upon his onboard weather information, a 30-degree deviation left of course would be required to navigate around the area of precipitation. The pilot also asked the controller, "if you see different on the live radar let me know." The controller responded, saying his radar was a few minutes behind, and that the pilot's on-board weather may be more accurate. The pilot replied, "yeah mine's a little later than yours so…" The controller informed the pilot that he could turn left to deviate around the precipitation, or he could turn right and "get around the back side of it." The controller then cleared the airplane for a deviation left of course, and instructed the pilot to resume a direct course to SPA when able. There was no recorded response from the pilot to this transmission. Between 1624 and 1627, radar data showed the airplane begin a slight right turn, followed by a left turn of about 90 degrees, and the airplane's altitude varied between 11,700 feet and 12,400 feet. At 1627, the controller asked the pilot if he was attempting to deviate around weather and if he needed assistance. The pilot responded, "uh I'm just going a little bit to the left to the weather niner six five." The controller instructed the pilot to advise when he was reestablished on course to SPA, and the pilot acknowledged. From about 1627:26 to 1629:16, the airplane continued a descending left turn to a northwesterly heading. At 1628:22, the controller again asked the pilot if he needed assistance. The pilot did not reply, and the controller queried the airplane a second time, to which the pilot responded, "niner six five go ahead." The controller asked again if he needed assistance, saying that the airplane was below its assigned altitude, and the pilot responded, "Uh I do need a little assistance niner six five I'm trying to get back to twelve niner six five." During the next several exchanges, the controller asked the pilot if he was still descending, if he needed further assistance in avoiding the weather, and advised of traffic nearby. The pilot repeated that he was attempting to climb back to 12,000 feet, however, radar data showed that the airplane remained at an altitude about 9,500 feet. When queried about his reason for the descent, the pilot replied, "uh just a lot of weather here I'm working on it niner six five." About 1631, the airplane initiated a right turn and climbed to about 9,800 feet, before entering a steep, 540-degree right turn, during which the airplane descended to about 7,300 feet in about 23 seconds. About 1637, the airplane began to track west on a heading of about 270 degrees, before turning slightly left onto a heading of about 210 degrees. The airplane continued to descend to an altitude about 6,500 feet. The controller again asked the pilot if he required emergency assistance, and asked the pilot to verify that the airplane was climbing. No response was received from the pilot. About 30 seconds later, the controller asked if the pilot wanted to land at nearby Charleston airport (CRW), or if he intended to continue on a 270-degree heading. The controller also noted that the airplane was still descending. The pilot responded, "I'm working on the climb niner six five." About a minute later, the controller informed the pilot that he was still observing the airplane in a descent, and instructed him to climb and maintain a heading of 270 degrees. The pilot responded with the airplane's call sign, and the controller asked him to read back the instruction. The pilot then responded, "two seven zero niner six five." At 1640:53, the controller asked the pilot to verify the airplane's heading, and the pilot stated, "uh I'm flying a two seven zero and climbing nine six five." However, the airplane remained on an approximate 210-degree heading. About 3 minutes later, the controller called the airplane and stated, "November nine six five uh are you still turning to the right uh but now I am showing you to the uh northwest of some moderate to heavy precipitation (unintelligible) continue on your current heading you will go through some moderate precipitation I'm not sure if there's anything convective in that weather uh if you wanna turn now to the right to get away from that uh let me know but right now I do show you still going through some moderate to heavy precipitation I see that you're in the climb are you turning for Spartanburg or would you need more assistance around the weather that I'm showin." The pilot's response was largely unintelligible. The controller again asked the pilot to verify the airplane's heading, and the pilot stated, "two four er two seven zero niner six five." No further transmissions were received from the accident airplane. From about 1645 to about 1652, radar data showed the airplane climb to an altitude about 12,700 feet, then begin a series of erratic turns in a generally eastbound direction until entering a rapid descent before radar contact was lost. Two witnesses near the accident site observed the airplane as it overflew their home. They described the sound of the engine as "loud," but stated that it was fading in and out. They both stated that the airplane was in a nose-down, right bank attitude as it descended into trees. They subsequently heard the sound of impact, but did not see any smoke or fire in the vicinity of the crash site. The witnesses reported that the weather was overcast, and that it began raining about 10 minutes after the accident. Another witness stated that he observed the last several seconds of the flight prior to impact. He stated that his attention was drawn to the airplane when he heard the engine "sputter then rev up loud in 2 or 3 cycles." He went outside and saw the airplane as it passed near his home in a wings-level, nose-down attitude. He stated that the airplane's descent was "very steep." The airplane disappeared behind a ridge line, and he almost immediately heard a "thud," then called 911 to report the accident. PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate with ratings for airplane single engine land and sea, airplane multiengine land, and instrument airplane. He also held a flight instructor certificate with ratings for airplane single and multiengine and instrument airplane. His most recent FAA second-class medical certificate was issued in September 2013. In an insurance application dated October 2013, the pilot reported 200 hours in the previous 12 months, 50 hours in the previous 3 months, and a total of 205 hours in the accident airplane make and model. Review of the pilot's personal logbooks revealed that he had accumulated a total flight time of about 1,024 hours. In the 6 months prior to the accident, the pilot logged 10 hours in the accident airplane, 6.2 hours of actual instrument experience and 7 instrument approaches. AIRCRAFT INFORMATIONThe airplane was manufactured in 1978, and was equipped with a Lycoming TIO-540 series, 300 hp turbocharged reciprocating engine. The most recent annual inspection was completed on May 17, 2013, at a total aircraft time of 3,344.8 hours. METEOROLOGICAL INFORMATIONA series of SIGMETs were issued for the Kentucky, Ohio, and West Virginia area on the day of the accident, beginning about 1155. These SIGMETs warned of a line of weather about 40 miles wide that contained embedded thunderstorms and was moving from west to east with cloud tops to 34,000 feet. Additionally, several AIRMETs were valid for the area of the accident site about the time of the accident. The AIRMETs forecasted moderate icing between the freezing level and 20,000 feet, moderate turbulence below 8,000 feet and between 7,000-18,000 feet, forecasted instrument meteorological conditions with ceilings below 1,000 feet, and visibility below 3 miles with clouds, precipitation, and mist. The pilot was not provided any information regarding AIRMETs or SIGMETs by ATC. An Area Forecast issued at 1345 and valid for the accident time forecasted a broken ceiling at 6,000 feet with cloud layers through 25,000 feet. Scattered light rain showers and thunderstorms were forecast with tops to 38,000 feet. A National Weather Service (NWS) Surface Analysis Chart for 1700 depicted a cold front stretched from western Pennsylvania southwestward into western Kentucky. A trough stretched across the area of the accident site from southeastern Pennsylvania to eastern Kentucky. A surface low pressure center was located in western Pennsylvania, with a surface high pressure center located in central Illinois. The NWS Storm Prediction Center Constant Pressure Charts for the area surrounding the accident site depicted a low-level trough just east of the accident site at 2000 EDT. Areas near and ahead of troughs are typically associated with enhanced lift, clouds, and precipitation. The nearest upper air sounding to the accident site was located in Roanoke, Virginia (KRNK), about 77 miles southeast of the accident site. The 2000 EDT sounding data from RNK indicated a conditionally unstable environment in most layers from the surface through 24,000 feet. This environment would have been conducive to cloud formation and precipitation in areas where a frontal boundary or trough was nearby. Data also indicated that clouds were likely from 9,000 feet through about 14,000 feet, with areas of moderate rime icing. The freezing level was located about 9,900 feet. Sounding data also indicated a surface wind from 260 degrees at 11 knots. Wind direction remained out of the west through about 24,000 feet, with speeds over 50 knots about 15,000 feet. Several areas of possible clear-air turbulence were identified from the surface through 15,000 feet. Satellite imagery from 1645 and 1715 EDT indicated abundant cloud cover over the area of the accident site, with clouds moving from southwest to northeast. Several overshooting tops, a strong indicator of updraft activity, were observed in the area of the accident site and throughout central West Virginia about the time of the accident. Infrared analysis of the satellite data indicated that the cloud tops in the area of the accident site about the time of the accident were approximately 29,000 feet. The closest NWS weather surveillance radar Doppler (WSR-88D) was located in Charleston, West Virginia (KRLX), about 16 miles west-northwest of the accident site. The strength of the radar return, also referred to as echoes or reflectivity, is measured in decibels of Z (dBZ) on a scale from -30 to greater than 75. These values are categorized by the NWS into video integrator and processor, (VIP) levels. VIP Levels 1 and 2 (15-19 dBZ and 30-39 dBZ, respectively) are "very light" to "light to moderate," with possible light to moderate turbulence and lightning with rainfall from .01-.21 inches per hour; VIP Levels 3 and 4 (40-44 dBZ and 45-49 dBZ, respectively) are "strong" and "very strong," and associated with severe turbulence and lightning with rainfall around .48 inches to 1.1 inches per hour; VIP Level 5 (45-49 dBZ), "intense," is associated with severe turbulence, lightning, hail likely, and organized surface wind gusts, with rainfall around 2.5 inches per hour; VIP Level 6 (55-75 dBZ), "extreme," is associated with severe turbulence, lightning, large hail, and extensive surface wind gusts with rainfall of over 5.6 inches per hour. Base reflectivity radar imagery correlated with the accident airplane's flight track indicated that between 1620 and 1630, the airplane passed through an area of precipitation with echoes between 30-50 dBZ. About 1645, the airplane again entered an area of precipitation, with echo values between 15 and 40 dBZ. The airplane continued in these echoes for the remainder of the flight. Data also indicated several lightning flashes in the vicinity of the airplane around the time of the accident. There were several PIREPs for the area around the accident site around the time of the accident. At 1722, a deHavilland DHC-8-100 located about 99 miles northeast of the accident site reported light rime icing at 15,000 feet. At 1739, a Mooney M20 located about 72 miles north of the accident site reported moderate rime icing at 10,500 feet, and stated that between 10,500 and 11,000 feet, the ice was "rapidly forming." At 1743, a Piper PA-34 located about 15 miles southwest of the accident site reported light turbulence and moderate rime icing at 13,000 feet, and remarked that the icing became light at 11,500 feet. At 1804, a Cessna 550 located about 32 miles south of the accident site reported light rime icing between 12,000 feet and 16,500 feet. Yeager Airport (CRW), Charleston, West Virginia, was located about 13 nautical miles northwest of the accident site at an elevation of 981 feet. The 1654 automated weather observation included calm winds, 8 miles visibility, light rain, a broken cloud layer at 7,000 feet, an overcast cloud layer at 9,500 feet, temperature 15 degrees C, dew point 14 degrees C, and an altimeter setting of 30.02 inches of mercury. Remarks included that rain began at 1601 and ended at 1631, began at 1648 and ended at 1652, and thunderstorm ended at 1623, moving east. Remarks also advised of the presence of valley fog. There was no record of the pilot receiving a weather briefing from a Flight Service Station or through the DUAT or DUATS systems. AIRPORT INFORMATIONThe airplane was manufactured in 1978, and was equipped with a Lycoming TIO-540 series, 300 hp turbocharged reciprocating engine. The most recent annual inspection was completed on May 17, 2013, at a total aircraft time of 3,344.8 hours. WRECKAGE AND IMPACT INFORMATIONThe wreckage was located on a densely-wooded hillside at an elevation of about 1,400 feet. The initial impact point was identified by broken tree branches and the right wingtip fairing. The wreckage path continued from the initial impact point on an approximate 360-degree heading, and measured about 300 feet in length. Several 3-inch diameter tree branches displaying 45-degree cuts were identified along the wreckage path, and pieces associated with both wings, the vertical stabilizer and rudder, and left and right horizontal stabilizers were located. Terrain at the accident site and disposition of the wreckage precluded thorough examination. The wreckage was recovered, and examination of the airframe and engine was scheduled for a later date. A wreckage layout and examination was conducted on May 14, 2014, at a secure storage facility. Both left and right wings were destroyed and separated from the fuselage at their roots. The left aileron and its balance weight remained attached. Control continuity was established from the aileron bellcrank, which was separated at its attach points, to the wing root, where the control cables exhibited signatures consistent with overload failure. The left wing flap was separated and broken into two sections. The right aileron was separated from the wing and fragmented. Right aileron control continuity was established from the bellcrank, which was separated at its attach points, to the wing root. The cable ends displayed signatures consistent with overload failure. The vertical stabilizer was separated and displayed impact damage. A top portion of the rudder remained attached, and the bottom portion of the rudder was separated. The rudder control cables were cut by recovery personnel. The "T" tail stabilator was separated from the vertical stabilizer and was destroyed. One stabilator control cable was cut by recovery personnel; the other displayed signatures consistent with overload failure. The fuselage, cockpit area, and instrument panel were destroyed. The engine was separated from the airframe and extensively impact-damaged. All engine accessories, with the exception of a portion of one magneto, were separated on impact. The oil sump, part of the accessory case, exhaust and intake tubes, turbocharger, and waste gate assembly were all impact-damaged and separated from the engine. The engine was rotated by hand at the crankshaft flange, and valve train and drive train continuity were confirmed to the accessory section. A borescope examination of the cylinders revealed no anomalies. The turbocharger compressor wheel was impact-damaged. The turbine wheel was intact and exhibited light gray and light brown coloration. No indication of contact between the compressor blades and housing was observed. No coking or oil deposits were observed in the compressor housing. The exhaust bypass valve was impact damaged and partially open. The propeller hub was fractured and the propeller was separated from the engine. One blade remained attached to the hub, and exhibited s-bending and leading edge gouging and polishing. The other blade was separated from the hub and exhibited slight s-bending, leading edge gouging, and curling at its tip. The gyroscopic rotors from the airplane's attitude indicator and directional gyro were recovered and disassembled for examination. Both the attitude indicator and directional gyro rotors and rotor housings exhibited rotational scoring consistent with operation at the time of impact. An Appareo Stratus receiver, as well as an Apple iPad, were located in the wreckage. The Stratus is a portable unit that receives traffic information from the Automatic Dependent Surveillance Broadcast (ADS-B) system, and also receives weather data via the Flight Information Services Broadcast (FIS-B) system. Weather information available through FIS-B includes NEXRAD radar data, Significant Meteorological Information advisories (SIGMETs), Airmen's Meteorological Information (AIRMETs), Notices to Airmen (NOTAMs), and pilot reports (PIREPs). This data would have been displayed to the pilot graphically via the iPad. No oxygen tanks or oxygen masks were located in the wreckage. ADDITIONAL INFORMATIONIndianapolis Air Route Traffic Control Center Interviews As part of the investigation, an NTSB air traffic control specialist and an NTSB meteorologist conducted interviews of personnel at the Indianapolis Air Route Traffic Control Center (ZID ARTCC), including the meteorologist (MET) on duty at the time of the accident, the front line manager (FLM) on duty at the time of the accident, and the sector 24 radar controller (R24), who was in direct contact with the accident airplane. MET Interview The MET stated that his workload on the day of the accident was heavy. He recalled a cold front moving eastward with lightning and embedded thunderstorms, with tops to 30,000 feet. He stated that his weather briefing on the day of the accident included information about heavy showers, thunderstorm activity, icing conditions, turbulence, and strong low-level wind conditions. He stated that this information was made available to the controllers via the electronic status information system (ESIS). ZID ARTCC Front Line Manager Interview The FLM stated that she had not reviewed audio or video replays of the accident. She stated that she was not performing any other duties at the time of the accident. When asked to rate the air traffic load at the time of the accident a scale from 1 to 5 (5 being the heaviest traffic), she stated that she would classify the traffic load as a 4. When asked to classify the traffic complexity using the same scale (5 being the most complex), she stated the traffic complexity at the time of the accident was 3. She stated that the controller staffing at the time of the accident was "typical." When asked about the weather at the time of the accident, she recalled a band of precipitation in the southeast portion of the airspace, but was not aware of any convective activity. She had received a weather briefing from the center weather service unit (CWSU), but recalled no mention of severe or convective weather in the briefing. She stated that controllers rarely, if ever, ask for CWSU-produced weather products while on position. She said that her interaction with the CWSU was limited to cases of extreme turbulence or unexpected weather. She first became aware of the accident airplane when another area supervisor called to ask if she knew about the airplane, and was told that it might be in distress. As a result of the call, the FLM went to observe the R24 controller as he handled the airplane. The R24 controller stated to her that the pilot was having difficulty maintaining his assigned altitude, but that he sounded "fine." The FLM then listened to the accident pilot's radio transmissions and also believed he sounded "fine." She stated she did not consider the accident airplane to be in an emergency situation until radar and radio contact was lost, and did not recall anyone discussing or considering declaring an emergency on behalf of the pilot. She could not recall any past training at ZID on emergency handling procedures or severe/hazardous weather training. R24 Controller Interview The R24 controller was asked to rate the air traffic load about the time of the accident on a scale from 1 to 5 (5 being the heaviest); he classified the traffic load as a 5. When asked to classify the traffic complexity using the same scale (5 being the most complex), he stated the traffic complexity at the time of the accident was 4. He recalled the weather conditions at the time included a long line of weather extending about 100 miles, with reports of moderate turbulence and areas of extreme precipitation around the Charleston, WV VOR. He stated that he discussed the weather with the pilot, and ultimately approved the pilot's request to deviate 30 degrees left of course. He subsequently observed the accident airplane continue south before beginning the left turn. He stated that the airplane appeared as though it was attempting to "pick" through the weather. He recalled the FLM coming over to his position and asking him questions, but stated that she did not provide any specific instruction on the handling of the airplane. At one point, he noticed the airplane turning north and descending, and asked the pilot if he needed assistance. He observed the airplane as low as 6,800 feet as it continued its turn back toward the weather, and he assigned the airplane a heading of 270 degrees and advised the pilot to return to his assigned altitude of 12,000 feet. As he continued to monitor the airplane, he noted that it appeared to be flying a heading of 210 degrees rather than the assigned 270 degrees. The controller asked the pilot to confirm the airplane's heading, and again asked if he required assistance. The pilot indicated that he was "okay" and continuing to climb. Radio contact was lost shortly thereafter. The airplane continued to climb to 12,000 feet before beginning a rapid descent, and a minimum safe altitude warning (MSAW) alert was issued. The last altitude at which the controller recalled observing the airplane was 2,300 feet. He stated that he had not considered the situation to be an emergency until the pilot stopped responding to radio transmissions, followed by the loss of radar contact. He did not declare an emergency on behalf of the pilot because he thought that the pilot's voice sounded calm and felt that the pilot was in control of the airplane. When asked about the weather information available to him, the R24 controller stated that he was provided a general weather briefing by his supervisor prior to starting his shift, and that the briefing had included the potential for turbulence. He stated that he frequently checked the ESIS to stay apprised of potential issues that could impact his sector. When asked about the limitations of the center's weather radar and processor data (WARP), which depicted weather conditions on the controller's screens, the controller stated that he knew it was not completely accurate and that the data was delayed, but he did not know by how much. He could not recall if any SIGMETs were valid, or if he had provided that information to the accident pilot. FAA Order 7110.65, "Air Traffic Control" 2-6-2 HAZARDOUS INFLIGHT WEATHER ADVISORY SERVICE (HIWAS) Controllers must advise pilots of hazardous weather that may impact operations within 150 NM of their sector or area of jurisdiction. Hazardous weather information contained in HIWAS broadcasts includes Airmen's Meteorological Information (AIRMET), Significant Meteorological Information (SIGMET), Convective SIGMET (WST), Urgent Pilot Weather Reports (UUA), and Center Weather Advisories (CWA). 2-1-25. SUPERVISORY NOTIFICATION Ensure supervisor/controller-in-charge (CIC) is aware of conditions which impact sector/position operations including, but not limited to, the following: a. Weather. b. Equipment status. c. Potential sector overload. d. Emergency situations. 10-1-1. EMERGENCY DETERMINATIONS a. An emergency can be either a Distress or an Urgency condition as defined in the "Pilot/Controller Glossary." b. A pilot who encounters a Distress condition should declare an emergency by beginning the initial communication with the word "Mayday," preferably repeated three times. For an Urgency condition, the word "Pan-Pan" should be used in the same manner. c. If the words "Mayday" or "Pan-Pan" are not used and you are in doubt that a situation constitutes an emergency or potential emergency, handle it as though it were an emergency. d. Because of the infinite variety of possible emergency situations, specific procedures cannot be prescribed. However, when you believe an emergency exists or is imminent, select and pursue a course of action which appears to be most appropriate under the circumstances and which most nearly conforms to the instructions in this manual. Weather Radar Data NTSB Safety Alert SA-017 warns pilots of the latencies inherent in the processes used to detect and deliver NEXRAD data from ground stations to the cockpit. The alert states the age indicator associated with an image on a cockpit display does not reflect the age of the actual weather conditions, but of the mosaic image created by the service provider. Therefore, weather conditions depicted on a mosaic image will always be older than the age indicated on the display. In extreme latency situations, these images may be as many as 15-20 minutes older than their indicated age. These limitations should be taken into consideration when utilizing in-cockpit NEXRAD displays for in-flight decision making, as movement and/or intensification of weather could adversely affect safety of flight. Physiological Factors Hypoxia Hypoxia is a state of oxygen deficiency in the body that can occur at high altitudes as a result of the decreased pressure in the atmosphere. For this reason, the FAA requires the use of supplemental oxygen for pilots flying unpressurized aircraft at altitudes above 12,500 feet for more than 30 minutes, and at all times above 14,000 feet. According to FAA Advisory Circular (AC) 61-107B, the portions of the brain governing judgment and cognitive skills are the first to show degraded function when the body enters a hypoxic state. Other signs and symptoms include rapid breathing, poor coordination, fatigue, nausea, headache, dizziness, and a feeling of euphoria. The AC stated that, while significant effects of hypoxia usually do not occur in a healthy pilot at altitudes below 12,000 feet, there is no definitive altitude at which the effects of hypoxia begin or end. The onset of hypoxia is insidious, and it can be difficult for pilots to recognize the symptoms and take corrective action before becoming impaired. If hypoxia is suspected, pilots should don oxygen masks immediately and descend to an altitude below 10,000 feet. Spatial Disorientation The FAA Civil Aeromedical Institute's "Intro to Aviation Physiology" defines spatial disorientation as a loss of proper bearings or a state of mental confusion as to position, location, or movement relative to the position of the earth. Factors contributing to spatial disorientation include changes in acceleration, flight in instrument meteorological conditions (IMC), frequent transfer between visual meteorological conditions (VMC) and IMC, and unperceived changes in aircraft attitude. The publication states that pilots flying in IMC are more susceptible than usual to the stresses of flight, such as fatigue and anxiety, and any event that produces an emotional upset is likely to disrupt the pilot's mental processes, making them more vulnerable to illusions and false sensations. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy and toxicological testing was conducted on the pilot by the Office of the Chief Medical Examiner, Charleston, West Virginia. The cause of death was listed as "catastrophic injuries received in a small aircraft crash." Toxicological testing was negative for ethanol and drugs. Liver tissue specimens contained carboxyhemoglobin in a saturation of 4.4%; a finding that does not suggest carbon monoxide poisoning. Additional toxicological testing was conducted on specimens from both the pilot and passenger by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. No tested-for drugs were detected. Carbon monoxide and cyanide testing could not be completed, as no blood was available for testing. Ethanol was detected in muscle and liver samples of both occupants; however, it is likely that the ethanol was from sources other than ingestion. In the pilot's application for an FAA medical certificate about 6 months prior to the accident, the pilot did not report any preexisting medical conditions, and no significant issues were identified by the aviation medical examiner who issued the certificate.