Air Tractor AT-502 N4556S

Summary

On 22 September 2012 at about 00:00 local time, a Air Tractor AT-502 registered N4556S, operated by Thiel Air Care Inc, was involved in an accident near Firebaugh, California, 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

22 September 2012 at 00:00

Classification

Accident

Location

Firebaugh, California, United States

Coordinates

36.8064, -120.6222

Aircraft

Air Tractor AT-502

Registration

N4556S

Category

Airplane

Year built

1991

Engines

1

Operator

Thiel Air Care Inc

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Firebaugh → Firebaugh

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR12LA433

Nobody was injured.

The pilot’s decision to continue the takeoff after the engine stopped producing its full-rated torque while operating in high-density altitude conditions and his subsequent failure to maintain clearance from the power transmission wires.

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

Read the full NTSB narrative

The pilot ferried the airplane to a private ag-operating airstrip where it was fully fueled, and 400 gallons of defoliant were loaded in the hopper. During the takeoff roll for the aerial application flight, the pilot noticed that the engine was not producing its full-rated torque, but he chose not to abort the takeoff. The pilot reported that, when the airplane reached the end of the runway, it lifted off but would not climb out of ground effect. As the airplane approached power transmission wires about 0.5 mile from the airstrip, the pilot began dumping the defoliant load to gain altitude. Dumping the load resulted in the airplane gaining some altitude, but, simultaneously, the airplane's nose pitched up, which increased drag and stopped the climb. The airplane struck the wires and landed hard in an open field. Postaccident examination of the engine found no preimpact mechanical anomalies that would have precluded normal engine operation. It is likely that the engine was not producing its full-rated torque because the density altitude was 2,400 feet (as compared to the field elevation of 236 feet), which reduced the available engine torque.

Quoted verbatim from the NTSB record.