ERA25LA222

NTSB accident investigation · Dehavilland DHC-6 Twin Otter · Tullahoma, TN · June 8, 2025

Accident · Serious injuriesClass 3 · LimitedPreliminary report
Date
June 8, 2025, 12:20 local (17:20 UTC)
Place
Tullahoma, TN
Injuries
6 serious, 15 uninjured
Damage
Substantial damage
Phase of flight
Takeoff
Aircraft
N166DHDehavilland DHC-6 Twin Otter
Defining event
Takeoff: Loss of engine power (partial)
Weather
Visual (VMC) · Day
Status
Investigation ongoing
Investigation class
Class 3
NTSB office
Eastern Region Aviation
Parties
TSB, FAA FSDO
FAA report
20250608006759A
Case key
200284

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Preliminary report

What NTSB knew early in the investigation. It may change in the final report.

On June 8, 2025, about 1220 central daylight time, a DeHavilland DHC-6 Twin Otter, N166DH, was involved in an accident near Tullahoma, Tennessee. The commercial pilot and five passengers were seriously injured, and 15 passengers were not injured. The flight was being conducted as a 14 Code of Federal Regulations Part 91 skydiving flight. The pilot was attempting to take off from runway 24 at the Tullahoma Regional Airport (THA), Tullahoma, TN. The accident flight was his fourth flight in the airplane that day. The pilot stated the takeoff was normal and he raised the flaps once the airplane was clear of obstacles. When the airplane was about 500 ft above the ground, the pilot noticed asymmetrical thrust on the engines while syncing the propellers. He said, “In the following seconds, I continued trying to sync the props and was getting unusual feedback in the controls. I didn’t notice any loss of power in the gauges, but something felt a miss.” The pilot lowered the nose of the airplane and saw the altitude level off, and airspeed decrease. The pilot determined that the left engine had lost power. He initiated “engine out procedures” and turned left, back to the airport to try and land on runway 36. The pilot could not remember if he secured the left engine; however, he did remember adding flaps as per the engine-out procedures. The pilot said he tried to maintain airspeed above the single-engine minimum control speed (Vmc), but the airplane continued to descend. The pilot was unable to make it back to the airport and chose to land in a field. There were two trees in the field that he was unable to avoid, and the airplane impacted the trees. The airplane came to rest upright, but the left wing, left engine and the tail section separated from the airframe, resulting in substantial damage. The right wing and engine remained secured to the airframe. There was no postimpact fire. The airplane wreckage was recovered and taken to a secure facility for further examination.

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Aircraft

Registration
N166DH
Reported as
Dehavilland DHC-6 Twin Otter
Category
Airplane
Serial number
66
Built
1967
Airframe hours
26,616
Damage
Substantial damage
Flight
Skydiving · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · September 10, 2024
Airport
THA · Tullahoma Rgnl/Wm Northern Fld, runway 06/24, 5,501 × 100 ft, asphalt
Equipment
Unknown

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Weather

Conditions
Visual (VMC) · Day
Wind
270° at 14 knots
Visibility
10 statute miles
Temperature
81 °F, dew point 64 °F
Altimeter
29.86 inHg
Observed at
KTHA
METAR
METAR KTHA 081735Z AUTO 27014KT 10SM FEW038 FEW044 SCT055 27/18 A2986

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.

Other investigations on N166DH · 1

Matched to the same aircraft by N-number and date.