Loss of control in flight: Air Tractor AT-802F Fire Boss, N10122, fatal accident occurred on July 10, 2024, near Helena, Montana

• Location: Helena, Montana 
• Accident Number: WPR24FA238 
• Date & Time: July 10, 2024, 12:10 Local
• Registration: N10122 
• Aircraft: AIR TRACTOR INC AT-802A 
• Aircraft Damage: Substantial 
• Defining Event: Loss of control in flight 
• Injuries: 1 Fatal 
• Flight Conducted Under: Public aircraft

https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194667/pdf

https://data.ntsb.gov/Docket?ProjectID=194667

On July 10, 2024, about 1210 mountain daylight time, an Air Tractor AT-802A (Fire Boss) airplane, N10122, was substantially damaged when it was involved in an accident near Helena, Montana. The pilot was fatally injured. The airplane was operated as public use aircraft for the purpose of firefighting.

The pilot of the single-engine air tanker flew as part of a group of four airplanes and was in the No. 2 position. The group departed from their home airport in support of aerial firefighting efforts and arrived at the destination 1 hour and 44 minutes later. Once they arrived on scene, near the wildfire, they flew to a nearby lake to begin the water scooping portion of the mission; the accident occurred during the first scoop sequence.

Witnesses on the lake and in their homes reported that the lead airplane successfully completed its scoop and lifted off from the lake. The float-equipped accident airplane was beginning to scoop when witnesses observed the airplane “moving unsteadily” before the left wing dipped into the water, the right wing rose into the air, the airplane veered left and subsequently impacted the rock face. 

During the initial water scoop, the lead pilot transmitted an instruction to abort the scoop due to a tailwind. As the lead airplane climbed away from the lake, the accident airplane had descended toward the water. The pilot did not acknowledge the abort instruction, and the airplane began to drift to the left. A review of the airplane’s SpiderTrack flight tracking data showed that during the final 1,447 ft of the water scoop, the airplane drifted about 10° left while on the water. The lead airplane’s flight data showed that the accident airplane’s drift to the left, away from the middle of the waterway and toward the shoreline and rock face, occurred simultaneously with the lead airplane’s turn to the left. The pilot did not take any evasive action to avoid the rock face. 

According to the operator, this was the accident pilot’s first fire season. The pilot’s training history showed that during tactical flying, the pilot at times lost situational awareness, which led to a regression in fundamental flying skills and freezing at the flight controls. 

Given these documented deficiencies, the pilot likely experienced a similar degradation in performance during the accident sequence.

Postaccident examination of the wreckage revealed no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. 

Toxicology results indicated a low level of cetirizine in the pilot’s postmortem femoral blood; with the low level found, the pilot was not likely to have experienced any significant impairment effects at the time of the accident. Additionally, a very low level measured concentration of morphine was identified in the pilot’s urine. The positive toxicology result is nonspecific and may have been found after opioid drug use or poppy seed consumption. Given the low level detected, it is unlikely that the pilot was impaired by the effects of morphine at the time of the accident.

- Probable Cause: The pilot’s loss of situational awareness during the water scoop due to task overload while operating in a multi-airplane tactical firefighting environment, which resulted in the pilot’s failure to maintain directional control and the airplane’s collision with terrain. 

VFR encounter with IMC: Rans S-19 Venterra, N519JR, fatal accident occurred on August 26, 2024, near Crofton, Nebraska

• Location: Crofton, Nebraska 
• Accident Number: CEN24FA326
• Date & Time: August 26, 2024, 08:41 Local
• Registration: N519JR 
• Aircraft: RANS S19 
• Aircraft Damage: Destroyed 
• Defining Event: VFR encounter with IMC
• Injuries: 1 Fatal 
• Flight Conducted Under: Part 91: General aviation - Personal 

https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194999/pdf

https://data.ntsb.gov/Docket?ProjectID=194999

On August 26, 2024, about 0841, central daylight time, an experimental, amateur-built Rans S19 airplane, N519JR, was destroyed when it was involved in an accident near Crofton, Nebraska. The pilot sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The airplane departed in daylight, visual weather conditions and proceeded along a meandering flight path before heading towards Yankton, South Dakota, for an unknown destination. About an hour after departure, while over Yankton, the pilot made a telephone call to a friend to inquire about the weather and airport options, stating that he was unable to land due to the weather as he did not hold an instrument rating. The pilot was not instrument rated, the airplane was equipped for only visual flight rules (VFR) operations, and the weather conditions at the nearby airport included a cloud ceiling at 200 ft above ground level (agl) with 1/4-mile visibility in fog and light rain. The friend suggested two airports south of the pilot’s position with automated weather stations reporting VFR weather conditions. The friend also stated that the pilot seemed calm and did not mention if he was in instrument meteorological conditions (IMC). 

A NTSB weather study determined that a cold front and inversion in the area, along with lowand mid-level troughs, made for an environment conducive to sustained low-level cloud cover, moisture, and precipitation. A review of recovered flight track data from an onboard GPS unit revealed that about the time that the pilot called his friend, the airplane was at an altitude of 3,239 ft mean sea level (msl) tracking roughly southwest. The flight track remained consistent during the next 8 minutes for about 14 nm, suggesting that the pilot was in VFR conditions above the cloud tops.

The airplane then began a right turn to the west with a slow climb to a maximum altitude of about 4,000 ft msl. About 1 minute later, the airplane began an S-turn, followed by a descending left turn for less than a minute before the data was lost. The accident site was located about 3/4 nm northeast of the last data point. The weather study determined that the accident flight was likely in IMC from 3,500 ft msl down to 200 ft agl, with visibility restricted to 1/4 mile or less below the cloud cover. The study also noted that a band of rain showers was moving northeast across the accident site at the accident time, which likely further reduced visibility below the cloud layer and had associated convective turbulence.

A postaccident examination of the airplane revealed no evidence of mechanical malfunction or failure that would have precluded normal operation. However, flight control continuity could not be established due to impact damage.

It is unknown what, if any, weather information the pilot checked before or during the flight, or whether the nearby airport (at the time that the pilot called his friend) was the intended destination. However, the reported weather at that airport from more than 2 hours before the accident flight departed through the time of the accident consistently included low instrument flight rules (LIFR) conditions. (LIFR is defined as a ceiling below 500 ft agl and/or visibility less than 1 mile.)

The weather forecast information applicable for the accident time did not include any graphical or text AIRMETs for instrument flight rules (IFR) conditions, and no terminal aerodrome forecasts were available within 30 miles of the accident site. The National Weather Service (NWS) graphical forecast analysis products issued more than 3 hours before the accident flight departed forecast LIFR surface visibility for the area of the accident applicable about 1 hour 40 minutes before the accident and VFR surface visibility with a cloud ceiling at 2,300 ft msl (about 600 ft agl) for the area of the accident applicable about 1 hour 20 minutes after the accident. The weather conditions encountered by the accident pilot were worse than NWS forecasts valid for the accident time. Several pilot reports (PIREPs) reported cloud tops between 2,600 ft MSL and 3,500 ft MSL in the area.

Loss of external visual references during VFR flight presents a high risk of spatial disorientation and loss of control. Several risk factors for spatial disorientation were present in this accident: the lack of IFR flight instruments, the non-instrument rated pilot, and the weather conditions. Based on these factors, as well as the airplane’s flight track and the orientation and fragmentation of the wreckage consistent with a high-energy impact, the pilot likely experienced spatial disorientation after entering an area of rain, convective turbulence, and IMC which may have been higher than the surrounding cloud tops, and he subsequently lost control of the airplane.

- Probable Cause: The non-instrument-rated pilot's decision to continue visual flight into an area of low cloud cover and precipitation which resulted in an inadvertent encounter with instrument meteorological conditions and a loss of control due to spatial disorientation.

Loss of control in flight: Zenith Zodiac CH601 HDS, N6271F, fatal accident occurred on April 30, 2024, near Bristol, Indiana

• Location: Bristol, Indiana
• Accident Number: CEN24FA170 
• Date & Time: April 30, 2024, 14:18 Local 
• Registration: N6271F 
• Aircraft: Zenith CH601 
• Aircraft Damage: Substantial 
• Defining Event: Loss of control in flight 
• Injuries: 2 Fatal 
• Flight Conducted Under: Part 91: General aviation - Personal

https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194178/pdf

https://data.ntsb.gov/Docket?ProjectID=194178

On April 30, 2024, at 1418 eastern daylight time, a Zodiac CH-601 HDS airplane, N6271F, was destroyed when it was involved in an accident near Bristol, Indiana. The private pilot and pilotrated passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The private pilot and pilot-rated passenger were returning to their home airport following a personal flight. About 7 miles from the destination airport, the airplane’s airspeed increased, and it entered a steep descent. Witnesses reported that the airplane descended rapidly and impacted a wooded area. Witnesses also reported conflicting observations regarding whether the engine was operating normally. The engine examination did not reveal any preimpact anomalies, and the shattered and widely dispersed wooden propeller blade fragments were consistent with engine power at impact. The airframe examination did not reveal any preimpact mechanical malfunctions or failures that would have precluded normal operation.

Toxicological testing of the pilot identified ethanol at low levels in several of the specimens and was not detected in brain tissue. Based on these results, some or all of the small amount of detected ethanol may have been from postmortem production rather than alcohol consumption, and it is unlikely that ethanol effects contributed to the accident. 

As a result of his heart disease, the pilot was at some increased risk of a sudden impairing or incapacitating cardiac event, such as chest pain, arrhythmia, or heart attack. The autopsy identified no evidence of such an event. However, an acute cardiac event occurring immediately before death may leave no reliable autopsy evidence. Whether the pilot’s heart disease contributed to the accident could not be determined.

Toxicological testing of the pilot-rated passenger identified two oral medications commonly used to treat diabetes. People with medication-treated diabetes are at risk for both abnormally high blood sugar (from diabetes) and abnormally low blood sugar (from medication effects). Short-term effects of high blood sugar may include decreased cognitive performance, including slower information processing speed, decreased executive function and attention.

Low blood glucose may cause difficulty concentrating, impaired task performance, and, in extreme cases, diminished consciousness, seizure, and death. The pilot-rated passenger’s postmortem urine glucose concentration is inconsistent with a markedly high antemortem blood glucose; however, it provides no information about whether his blood sugar may have been low. It also is unknown if the pilot-rated passenger had less severe symptoms of diabetes, such as fatigue or blurred vision or chronic complications associated with diabetes, such as vision loss, neuropathy, or kidney disease

As a result of his heart disease, the pilot-rated passenger was at some increased risk of a sudden impairing or incapacitating cardiac event, such as chest pain, arrhythmia, or heart attack. The autopsy identified no evidence of such an event. However, such an event does not leave reliable autopsy evidence if it occurs immediately before death. It is unknown what role the pilot-rated passenger had, if any, in aircraft operations and flight safety. Whether the effects of the pilot-rated passenger’s use of metformin and glipizide or his heart disease contributed to the accident cannot be determined.

Although either occupant could have experienced a sudden incapacitating medical event while manipulating the flight controls during the descent, the remaining occupant may have had insufficient time or opportunity to recover the airplane before impact. However, the investigation could not determine which occupant, if either, was manipulating the flight controls at the time of the accident. Therefore, whether either occupant experienced an incapacitating medical event that contributed to the accident could not be determined. 

- Probable Cause: The pilot’s loss of control during the descent for reasons that could not be determined, which resulted in a steep descent into terrain.