Air Tractor AT-502 N15189

Summary

On 19 May 2024 at about 00:30 local time, a Air Tractor AT-502 registered N15189, operated by TRI Rotor Spray & Chemical, was involved in an accident near Covert, Kansas, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

19 May 2024 at 00:30

Classification

Accident

Location

Covert, Kansas, United States

Coordinates

39.2344, -98.7011

Aircraft

Air Tractor AT-502

Registration

N15189

Category

Airplane

Year built

1991

Engines

1

Operator

TRI Rotor Spray & Chemical

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Osborne → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN24LA193

Nobody was injured.

The improper maintenance of the fuel control unit, which resulted in air leakage and a loss of control of fuel flow to the engine.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

During an agricultural application flight, the pilot noticed a loss of thrust and adjusted engine power as needed. The subsequent application pass was normal; however, while turning the airplane around for another pass, he felt the “tail drop” and noticed that several engine gauges had exceeded limitations. The pilot attempted to reduce engine power but found that the engine was unresponsive to power control inputs and that the airplane was unable to maintain altitude. He chose to land on a nearby gravel road, during which the airplane impacted tree branches and ground looped into a ditch, resulting in substantial damage to both wings. After the airplane came to rest, the engine continued to run until the pilot cut off the fuel supply. Postaccident examination of the engine revealed an improperly torqued and safety wired P3 adapter on the fuel control unit (FCU). This allowed the two attachment screws, used to secure the P3 adapter to the main body of the FCU, to back off, which resulted in excessive air leakage and movement of the gasket between the adapter and the FCU main body. This leakage fluctuated when light finger pressure was applied to the P3 adapter that connected to the FCU main body. The P3 adapter’s seal with the FCU’s main body likely degraded over time because the screws backed off, allowing relative motion between the gasket and sealing surfaces. The intermittent air leakage compromised FCU fuel control capability, likely resulting in the FCU’s fuel flow metering valve to move to its minimum setpoint and the erratic engine behavior observed by the pilot. The date that the accident FCU was installed on the accident engine could not be determined based on maintenance records. The only entry indicating this FCU’s condition was on August 25, 2022, and noted that the FCU was already installed on the engine when received and was in serviceable condition during final inspection. The only maintenance performed on this FCU while installed on the accident airplane was changing the fuel filter.

Quoted verbatim from the NTSB record.