Premium research interface

The modern interface for aviation safety intelligence.

Search investigations, review source evidence, monitor watched reports, and trace long-term patterns from one calm, data-first workspace.

63k+
Reports indexed
1940-2026
Coverage
Recent
Last data refresh
Featured Report

Loading…

Loading featured report…

Loading…
Open Report

Safety trends by operating rule

Track fatal and non-fatal accident patterns across Part 91, Part 135, and Part 121 operations.

Loading trend charts…

Browse the aviation graph

Move quickly by aircraft, airport, operator, and time with indexes built for research, not wandering.

Last Data Update

By Decade

By Month

Aircraft Manufacturer

More manufacturers

Airports

More airports

Operators

More operators

About

Aviation safety reports, made easier to study

NTSB Reports is an independent research and search tool for public aviation accident and incident records. It brings NTSB aviation reports, structured fields, docket files, extracted figures, photos, videos, and update history into one searchable interface.

The goal is practical safety education: make it faster to find relevant investigations, compare similar events, review factual records, and understand the evidence behind probable-cause and preliminary reports.

The investigative work and source records belong to the National Transportation Safety Board and the published investigation record. This site is not affiliated with or endorsed by the NTSB.

FAQs

NTSB Report

December 30, 2004 · Aerostar 601 · N601DF

Hamilton, MT

Overview

Report Status
Final with probable cause
Event Type
Accident
Date
December 30, 2004
Injury Outcomes
No injuries (1 uninjured)
Location
Hamilton, MT
Aircraft
Aerostar 601
Tail Number
N601DF
Operator
Robert M Kline
Injuries
None
Aircraft Damage
Destroyed
NTSB Number
SEA05LA032

Immediately after taking off and raising the landing gear, the pilot noticed the left engine began to lose power. The airplane subsequently veered to the left before impacting up slopping terrain in a left wing low attitude, resulting in a fire breaking out which consumed the left side of the airplane. A postaccident examination revealed that the left engine had sustained thermal but no impact damage, and that the engine's right hand turbocharger had no thermal or impact damage. A further examination indicated that no restrictions were found in the center section of the turbocharger and there was no damage to the housing or the impeller; however, the impeller was frozen in the center section and would not turn. Indications of grooving and scraping from a lack of lubrication to the bearings and drive shaft was observed. No mechanical anomalies with the aircraft were noted by the pilot prior to takeoff which would have prevented normal operations.

NTSB Probable Cause

A partial loss of engine power due to the lack of lubrication and subsequent failure of the left engine's right turbocharger for undetermined reasons, and subsequent forced landing after takeoff. A factor was the unsuitable terrain for the forced landing.

Full Narrative

On December 30, 2004, approximately 1300 mountain standard time, an Aerostar 601 airplane, N601DF, was destroyed after impacting terrain following a loss of engine power during initial climb near Hamilton, Montana. The certificated commercial pilot, the sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed for the personal flight, which was conducted in accordance with 14 CFR Part 91, and a flight plan was not filed. The flight was originating at the time of the accident, with the destination being the Stevensville Airport (32S), Stevensville, Montana. In a telephone interview with the NTSB investigator-in-charge (IIC), the pilot stated that "almost immediately" after taking off on Runway 34 he retracted the landing gear, then noticed the left engine beginning to lose power as the airplane began to drift to the left. The pilot stated that because he was less than 100 feet above the ground, he didn't have time to "feather" the propeller. The airplane impacted up slopping terrain in a left wing low attitude, sliding to a stop and coming to rest in an upright position. The pilot reported that after he turned the master switch off and exited the aircraft, he noticed a fire starting to break out, which subsequently consumed the left side of the airplane. A Federal Aviation Administration (FAA) airworthiness inspector, who traveled to the accident site, reported that the left engine's propeller blades were bent almost straight back, indicating minimum engine power at impact, while the right engine's propellers revealed signatures consistent with the engine generating full power. The aircraft was subsequently moved to a secure facility at the Stevensville Airport for further examination. On January 20, 2005, an FAA airworthiness inspector, assisted by a certificated airframe and powerplant mechanic, conducted an examination of the aircraft's left engine. The examination revealed the engine, equipped with two Ray Jay turbochargers, sustained thermal damage due to a post crash fire. The oil lines feeding the turbochargers sustained thermal damage; however, the fittings were intact and no obstructions were noted. The wastegates were in the open position and moved freely. The intake hose on the left turbocharger was removed. There was no foreign object damage observed and the impeller was found to turn freely. When examined, the right turbocharger impeller would not turn, but no foreign object damage was noted. At this point the right turbocharger was removed for further examination. The right hand mounted turbocharger exhibited no evidence of thermal or impact damage. The center section of the turbocharger was checked for restrictions and none were found, and the exhaust side of the turbocharger revealed no damage to the housing or the impeller. The impeller was frozen in the center section and would not turn. The intake impeller was then removed from the shaft and the drive shaft was tapped out of the center section. The center of the drive shaft was observed to be discolored (black and blue) with round marks evenly spaced around the shaft that matched the oil holes found on the bearings. Indications of grooving and scraping from a lack of lubrication to the bearings and drive shaft was observed. The oil holes located in the bearings positioned in the center section of the turbocharger were clear of obstructions. Maintenance records revealed that on January 25, 2000, the left engine's right turbocharger was replaced and new oil lines installed. Recorded data also indicates that on March 28, 2004, both of the engine's turbochargers were replaced with overhauled ones. The recorded time on both left and right turbochargers at the time of the accident was 24.3 hours. The type certificate data sheet lists the takeoff manifold pressure at 29.9 inches for the engine with turbocharger installed. A normally aspirated IO-520 engine puts out approximately 24.5 inches at takeoff, a difference of 5.4 inches of manifold pressure at takeoff power. The pilot reported that there were no mechanical anomalies with the aircraft prior to takeoff which would have prevented normal operations. .

Flight

Event TypeAccident
Event Time13:00 MST
Nearest AirportRavalli Country Airport (0nm)
Runway34
Runway Length4200 ft
Runway Width75 ft
Flight Plan FiledNone
Flight Plan ActivatedNo
Aircraft FireGrd
Aircraft ExplosionNo

Aircraft

AircraftAerostar 601
Tail NumberN601DF
Aircraft CategoryAir
DamageDestroyed
OperatorRobert M Kline
Operating RulePart 91
Engines2
Engine TypeReciprocating
Engine DetailsLycoming · TIO-540 · Reciprocating · 290
Seats6

People & Injuries

Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 87 · Second Class · None

Conditions

ConditionsVMC
LightDaylight
WindCalm
Visibility3 sm
CeilingNone
Temperature / Dew Point30 C / 27 C
Altimeter29.62 inHg
Observation Time02:53
Weather SourceWFAC

Appendix: Source Data