# NTSB SEA95LA110: Garlick TH-1L, N27FL, Umpqua, OR, June 1, 1995 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: June 1, 1995, 09:05 local (16:05 UTC) - Place: Umpqua, OR - Coordinates: 43.350593, -123.539451 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.3506&lon=-123.5395&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report December 19, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 42158 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA95LA110 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42158/pdf - Page: https://openairdocs.org/ntsb/SEA95LA110 ## Probable cause THE PILOT'S FAILURE TO MAINTAIN CLEARANCE WITH A TREE, RESULTING IN A TAIL ROTOR BLADE STRIKE ON THE TREE WHICH DISABLED THE TAIL ROTOR. CONTRIBUTING TO THE ACCIDENT WAS THE 150-FOOT-HIGH ROCK BLUFF. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, maneuvering - object - tree(s) - clearance - not maintained, pilot in command (cause) - rotor system,tail rotor blade - blade strike (cause) - Loss of control - in flight, maneuvering - rotor system,tail rotor - disabled (cause) - load jettison - performed, pilot in command - In flight collision with terrain/water, descent - uncontrolled - terrain condition - cliff (contributing factor) ## Analysis WITNESSES SAW THE HELICOPTER STRIKE ITS TAIL ROTOR ON A TREE WHILE ATTEMPTING TO LIFT A 3,000 POUND LOG SECTION USING A 150-FOOT LIFT LINE. THE TREE STRIKE DISABLED THE TAIL ROTOR, RESULTING IN LOSS OF DIRECTIONAL CONTROL. THE HELICOPTER SUBSEQUENTLY IMPACTED AT THE TOP OF A 150-FOOT-HIGH ROCK BLUFF, THEN SLID OFF THE BLUFF, COMING TO REST IN AN INVERTED ATTITUDE ON A 50 TO 60 PERCENT SLOPE ABOUT 250 FEET BELOW THE INITIAL IMPACT POINT. ## Factual narrative On June 1, 1995, approximately 0905 Pacific daylight time (PDT), N27FL, a Garlick-converted TH-1L former military helicopter, received substantial damage in an inflight collision with a tree and subsequent collison with terrain approximately 6 miles northwest of Umpqua, OR. The commercial pilot, the sole occupant of the restricted-category helicopter, was fatally injured. The helicopter was owned by Garlick Helicopters, Inc. and operated by Intermountain, Inc. The flight was an external-lift logging operation conducted under 14 CFR 133, originating from Myrtle Creek, OR. Visual meteorolgical conditions existed at the time of the accident, and no flight plan had been filed. The operator stated in his report of the accident: We started logging [at] approximately 5:30-6:00 AM.... After about 2 hours we shut the helicopter down to fuel and make a maintenance inspection. The fueling and walk around lasted about 30 minutes. We lifted off about 9:00 AM and resumed logging operations. Before the pilot made one lift (a log) the accident occurred. ...The terrain was very steep with rock outcroppings and 50-100 [foot] bluffs, slopes average 50-100 [percent]. The logging supervisor, who was working under the helicopter at the time of the accident and who hooked the choker (lifting harness) to the helicopter's 150-foot-long lift line, stated the following to the responding deputy: ...he had just rehooked the choker to the long line and started to move out of the way when the long line started falling out of the sky. [He] said he thought the pilot had accidentally released the long line. [He] said he heard a loud pop. He looked up and noticed that the helicopter was going into a spin. The helicopter rotated approximately 1/2 of a turn before impacting the ground. [He] said pieces flew everywhere as the helicopter slid over the bluff backwards. Three witnesses who saw the accident from a vantage point approximately 3/4 to 1 mile east of, and several hundred feet below, the crash site reported the following to Douglas County sheriff's deputies: ...They saw the helicopter hovering near the trees. The tail rotor ran into the trees and sheared off. [They] saw the blades shear off and the helicopter went toward the river, slamming into the ground...The helicopter had started spinning, then went left side into the cliff. The helicopter had been working on both sides of a large fir tree that was near the log it was trying to [lift.] Investigators at the scene found the main wreckage on the slope approximately 250 feet below the point of initial ground impact (the top of a 150-foot-high rock bluff.) The wreckage was inverted and pointing downhill. The on-scene investigators spotted a section of tail rotor, along with freshly cut bare wood scars, in the tree adjacent to the pickup site. They also discovered sections of main rotor blade tip at the site of initial ground impact. The helicopter's lift line was hung up in the tree and was not attached to the helicopter; however, it was attached to the choker which was around a section of Douglas fir with dimensions given in the sheriff's report as approximately 5 feet 6 inches in diameter and 5 feet in length. This section was one of eight 5-foot sections cut in the middle of a tree 144 feet 6 inches long. The sheriff's report noted that the choker was installed on the log in such a fashion as to cause the log to roll downhill once it was pulled free from the tree. The responding deputy stated in the report that he had inspected the cuts at each end of this log section and that the cuts had been made all the way through. According to the sheriff's report, the logging supervisor stated to the responding deputy that he estimated the weight of the log section at 3,000 pounds. A separate calculation of the weight of the section, using the dimensions given above and specific gravity of commercial grade fir (0.36) obtained from an engineering reference source, yielded a section weight of 2,669 pounds. The gross weight of the helicopter, based on fuel loading of 700 pounds reported by the operator and a 3,000 pound log section, is estimated to have been approximately 9,200 pounds at the time of the accident. The Garlick Helicopters party representative to the investigation stated that the maximum load on the lift line is 4,000 pounds, and that the helicopter's maximum gross weight is 9,500 pounds. A later examination of the wreckage at Specialty Aircraft, Inc. of Redmond, OR on June 29, 1995 revealed that both tail rotor blades were broken off approximately 1 to 2 feet out from the blade hinges. One blade was broken back in rounded fashion at approximately a 60-degree angle. The other was broken back squarely at a 90-degree angle. The 90-degree gearbox case was broken apart with the main portion remaining attached to the tail rotor hub and blades. The other portion remained with the tail boom. An exposed gear on this portion of the gearbox displayed machined-off teeth. The tail rotor drive shaft exhibited a torsional overstress deformation, and was fractured at the point of this deformation. The tail boom was buckled approximately 30 degrees toward the right about 3 feet forward of the tail rotor location. Examination of the helicopter's maintenance history from April 10, 1995 until the accident revealed that the helicopter had experienced engine compressor stalls on two separate occasions. The first occurrence, on April 17, required three attempts to correct (change of fuel control, replacement of bleed band actuator, and a second change of fuel control) before the aircraft was returned to service on April 25. After the first two attempts, a technical-order compressor stall inspection was documented in the maintenance log. This inspection was not documented after the third attempt although a limited maintenance test flight was performed after the second fuel control change. The second occurrence took place on May 15, two weeks before the accident. This was written up as a compressor stall at full power. The corrective action for this was listed as "adjusted bleed band closure...." Between the last compressor stall and the accident, the helicopter underwent two 25-hour maintenance inspections, both of which incorporated engine operation tests. The aircraft maintenance records noted no engine operation anomalies from either of these two inspections. The helicopter underwent four separate scheduled maintenance inspections between April 10 and the accident: a 25-hour inspection on May 3 at 9,400.6 hours, a Phase AB inspection on May 10 at 9,419.5 hours, a 25-hour inspection at 9,443.8 hours (date unspecified), and a 25-hour inspection at 9,470.4 hours. Some steps in the Phase AB inspection checklist had not been signed, including: notes regarding 90- and 42-degree gearbox oil changes; tail rotor drive shaft covers; hydraulic fluid sampling; note regarding hydraulic fluid replacement; main fuel filter; tail rotor hub and blade; and tail rotor driveshaft. A table in the maintenance records dated May 1, 1995 indicated that the number 1 hanger bearing, which supports the tail rotor driveshaft, had 79 hours of service left. Between May 1 and May 31, maintenance records indicated the helicopter flew 107.3 hours. The tail rotor driveshaft bearings were signed off as "insp[ected and] found O.K." on the May 10 Phase AB inspection. Maintenance records indicate the tail rotor hanger assemblies have a 1,200 hour service life. The Garlick party representative provided technical data which indicates that exceeding service life by up to 10 percent is allowable. Representatives from the NTSB and Allied Signal Engines conducted a teardown of the T53-13B engine at Specialty Aircraft, Inc., Redmond, OR, on June 29, 1995. During the teard ## Aircraft - Registration: [N27FL](https://openairdocs.org/deregistered/N27FL-1996-06-17), registration cancelled 1996-06-17, S/N 157844 (OpenAirDocs) - Reported make and model: GARLICK TH-1L - Registry model: [Bell TH-1L](https://openairdocs.org/model/bell-th-1l) (registry code 1180817) (OpenAirDocs) - Category: Helicopter - Serial number: 6439 - Airframe hours: 9492 - Engines: LYCOMING T53-13B 1400 horsepower turbo shaft - Damage: Substantial damage - Flight: Other work use, Part 133 - Operator: Schuyler, Sid, doing business as Intermountain, Inc. - Registered owner: Garlick Helicopters - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, May 28, 1995, 24 hours before - Departed: 16S, MYRTLE CREEK, OR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 8,628 total, 384 in this make and model, 6,188 as pilot in command, 204 in the last 90 days, 84 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 48 °F - Altimeter: 29.00 inHg - Observed at: RBG, 14 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19950601043629A](https://openairdocs.org/incident/19950601043629A), Jun 1, 1995: Bell TH1L, Umpoua, OR, Substantial damage, 1 fatal. During hover for log pickup. Went into spin. Crashed. Tail rotor sheared off striking trees. No mechanical problems From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.