ERA14FA192

The pilot's loss of airplane control while operating in instrument flight rules conditions.

The pilot and passenger departed on an instrument flight rules flight with a cruise altitude of 12,000 ft. About 1 hour after takeoff, the air traffic controller advised the pilot of an area of moderate to extreme precipitation along the airplane's route of flight, and the pilot replied that he observed the same on his "radar." (The airplane was not equipped with airborne weather radar, rather the pilot was likely referring to ground-based weather radar data that he was viewing on a tablet computer.) The controller cleared the pilot to deviate 30 degrees left of course. The pilot did not acknowledge the clearance and continued on a southeasterly course for about 10 minutes. He then initiated a 180-degree left turn during which the airplane climbed to about 12,600 ft and then descended to about 9,700 ft. Overlaying the airplane's flight track on weather radar data showed that, during the 180-degree turn, the airplane passed through an area of moderate to very heavy rain with the possibility of hail, severe turbulence, and lightning. Observing the airplane's change in heading and altitude, the controller asked the pilot if he was attempting to deviate around weather and if he required assistance. The pilot replied that he was "going a little bit to the left to the weather." The controller instructed the pilot to advise when he was established back on course, and the pilot acknowledged. Over the next 4 minutes, the airplane continued on a northwesterly heading and descended to about 9,000 ft as it exited the area of precipitation. During this time, the controller contacted the pilot four separate times, advising him that the airplane was below its assigned altitude and asking if he needed assistance. The pilot did not respond to the first inquiry. His responses to the second and third inquiries were slurred, and his speech rate was markedly decreased. He stated that he needed assistance and that he was trying to get back to the assigned altitude. The pilot did not respond to the fourth inquiry. The airplane then began a gradual 360-degree right turn, during which its altitude varied between 9,100 and 9,900 ft. The controller again asked the pilot his intentions, and the pilot stated that he was climbing back to 12,000 ft and heading direct to his destination airport. When queried as to the reason for the airplane's descent, the pilot replied "just a lot of weather here I'm working on it." The airplane continued turning right for about 2 minutes, then entered a steep right turn during which it descended about 2,500 ft in less than 30 seconds. During the following 5 minutes, the controller repeatedly asked the pilot if he required assistance, instructed him to climb, and assigned the airplane a heading of 270 degrees; however, the airplane climbed slowly on a heading of about 210 degrees. The controller advised the pilot that if he continued on that heading, the airplane would encounter moderate precipitation. The pilot's response was largely unintelligible. ATC again asked the pilot to verify the airplane's heading, and the pilot responded in a confused manner, but the airplane continued on its heading of about 210 degrees. No further transmissions were received from the accident airplane. About 1 minute later, the airplane turned south, continued to climb, and entered an area of light to moderate precipitation. The flight continued for about 8 minutes, conducting a series of turns to the right and left before it reached an altitude of about 12,100 ft, then entered a rapid descent. Radar contact was lost shortly thereafter. Postaccident examination of the airframe, engine, and flight instruments revealed no evidence of preimpact anomalies, and there was no evidence of an in-flight breakup. No medical issues were identified with the pilot that may have contributed to the accident, and toxicological testing was negative for impairing substances and did not suggest carbon monoxide poisoning. The airplane was traveling at 12,000 ft for a portion of the flight, an altitude at which the use of supplemental oxygen is not required. While this does not preclude the possibility of a pilot developing hypoxia at that altitude, the airplane spent about 20 minutes below 10,000 feet, and the pilot's performance did not appear to improve during that time. Therefore, it is unlikely that the pilot was experiencing hypoxia. It could not be determined why the pilot was unable to maintain control of the airplane or why he did not request assistance from the controller. The extent to which the pilot had familiarized himself with the weather conditions along the route of flight before takeoff could not be determined, as there was no record of a weather briefing from an official, access-controlled source. However, the pilot indicated to the controller that he had "radar" in the cockpit, and a portable ADS-B receiver and tablet computer were found in the wreckage, suggesting that the pilot was receiving weather information during the flight, to include Next Generation Radar (NEXRAD) and significant weather advisories. Due to latencies inherent in the process of detecting weather at a ground site, compiling a mosaic image, and subsequently delivering that data to the cockpit, NEXRAD is not an accurate depiction of actual weather conditions and should not be used for tactical weather avoidance. The pilot's comment to ATC that "[my weather display is] a little later than yours" likely indicated that the pilot was aware of these limitations. However, it is likely that, based on the pilot's use of the word "radar," the controller assumed that the airplane was equipped with airborne weather radar, which would have provided real-time information to the pilot that could be used in tactical weather avoidance. Although they discussed the weather conditions, the pilot did not explicitly state, nor did the controller ask, what kind of weather information he was receiving. This may have led the controller to believe that the pilot was able to "pick through" the weather with real-time data. The pilot's inability to maintain altitude and heading likely alerted the controller that the pilot was experiencing a problem, and the controller subsequently asked the pilot a total of eight times over a period of about 15 minutes if he required assistance. However, despite apparently recognizing that the pilot was having difficulties, the controller failed to notify his supervisor of the situation as required. The controller also failed to ask specific questions to fully understand the difficulties the pilot was experiencing, and finally, he did not declare an emergency on behalf of the pilot, which would have ensured that the airplane was given priority handling. Further, the controller's supervisor was not performing other duties during the time that the controller was providing services to the airplane and should have been engaged in the situation. Although she was sitting only a few feet from the controller, she did not become aware of what was happening until another supervisor from a different area called and asked her what was going on with the airplane. Even then, the supervisor only monitored the situation momentarily before returning to her desk. Despite the shortcomings of air traffic control services provided to the pilot, the extent to which those services may have contributed to the outcome of the flight could not be determined as it is unknown how the pilot would have responded to any actions taken by the controllers.

Indianapolis 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 NEXRA