# NTSB NYC94LA097: Bell 47G3 Soloy, N121CD, Friendsville, MD, May 31, 1994 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: May 31, 1994, 07:35 local (11:35 UTC) - Place: Friendsville, MD - Coordinates: 39.660812, -79.399284 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.6608&lon=-79.3993&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report December 2, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 38766 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC94LA097 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/38766/pdf - Page: https://openairdocs.org/ntsb/NYC94LA097 ## Probable cause THE PARTIAL FAILURE OF THE TURBINE ENGINE FOR UNDETERMINED REASONS, DURING AN AGRICULTURE MANEUVER AT LOW ALTITUDE, OVER TERRAIN UNSUITABLE FOR AN AUTOROTATION. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, maneuvering - aerial application - reason for occurrence undetermined (cause) - Forced landing, descent - emergency - In flight collision with object, descent - emergency - object - tree(s) - terrain condition - none suitable (contributing factor) ## Analysis THE AERIAL APPLICATION FLIGHT HAD BEEN AIRBORNE FOR APPROXIMATELY 30 MINUTES, IN THE TURBINE ENGINE CONVERTED BELL 47. THE HELICOPTER WAS OVER HILLY TERRAIN WITH TREE LINES. THE PILOT WAS FLYING AN UPHILL RUN AT 30 TO 40 FEET ABOVE TREE LEVEL, AT 60 TO 65 MILES PER HOUR, WHEN THERE WAS A PARTIAL LOSS OF ENGINE POWER. THE PILOT ATTEMPTED TO FLY TO AN OPEN AREA WITH PARTIAL POWER. THE HELICOPTER STRUCK A TREE AS IT APPROACHED THE EDGE OF A CLEARING. AFTER THE HELICOPTER CAME TO REST ON THE GROUND, THE PILOT SHUT THE ENGINE DOWN WITH THE TWIST GRIP THROTTLE. THE TRANSMISSION, THE FREE WHEELING UNIT AND THE TAIL ROTOR GEARBOX WERE EXAMINED, AND NO DEFECTS WERE NOTED. EXAMINATION OF THE ENGINE REVEALED ACCIDENT RELATED IMPACT DAMAGE TO THE COMBUSTION LINER. THE LINER WAS REPLACED AND THE ENGINE PERFORMED NORMALLY DURING A TEST RUN. ## Factual narrative On May 31, 1994, at 0730 eastern daylight time, a Bell 47G3 Soloy, N121CD, owned by Helicopter Applicators, Inc., and piloted by Dirk Dekker, was destroyed during a forced landing to a hillside near Friendsville, Maryland. The pilot was seriously injured. Visual meteorological conditions prevailed and no flight plan had not been filed for the flight operating under 14 CFR 137. The helicopter had departed at approximately 0700 to perform an agriculture application mission. The pilot reported that after about 30 minutes of flying he was established on an up hill application run, about 30 to 40 feet above the trees, and at an airspeed of 60 to 65 miles per hour (MPH). In the NTSB Form 6120.11, the pilot stated: "...[I] estimate 15 to 20 seconds after spray on, I felt considerable shuddering, slight yaw, change in control feel (roughness), a difference in sound and some loss of power. I ...made a right turn towards the clearing I had observed...I tried to fly to the clearing using what power may have been left ...hoping to clear the trees and build up more rotor RPM into the clearing to make some sort of landing. I could not avoid a tree in my path at the edge of the clearing, and collided with it, ending upright and nose down in the clearing...After the ground impact...I heard the turbine engine still running though it seemed at reduced RPM...[I] shut the engine down with the collective/twist grip throttle..." According to the Federal Aviation Administration (FAA), Baltimore Flight Standards District Office (FSDO) Inspector's report, the main transmission was disassembled and revealed no defects. This included the free wheeling unit and the tail rotor gearbox. According to the FAA, FSDO, Dallas, Texas, Aviation Safety Inspector's report, the engine was examined at Aviall Inc., in Dallas, Texas. The engine showed impact damage to the combustion liner and this component was changed to allow the engine to placed in condition for a test run. The engine was subjected to a functional test which lasted about 25 minutes. The report stated; "...The subject engine performed properly under all conditions during the test...." The Bell Helicopter Flight Manual for the Model 47G-3B-1, contains an Airspeed vs. Altitude Chart. This chart depicts the areas to avoid continuous operations in, in the event of an engine failure. The area of 65 MPH and 40 feet above the ground indicates that in the event of an power loss, "This region safe over smooth landing surface only." ## Aircraft - Registration: [N121CD](https://openairdocs.org/deregistered/N121CD-2017-02-28), registration cancelled 2017-02-28, S/N 3796, built 1967 (OpenAirDocs) - Reported make and model: BELL 47G3 SOLOY - Registry model: [Bell TH-13T](https://openairdocs.org/model/bell-th-13t) (registry code 1180813) (OpenAirDocs) - Category: Helicopter - Serial number: 3796 - Airframe hours: 8509 - Engines: ALLISON 250-C20B turbo shaft - Damage: Destroyed - Flight: Aerial application, Part 137 - Registered owner: Helicopter Applicators, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 29, 1994, 43 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; commercial; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 3,000 total, 2,785 in this make and model, 3,000 as pilot in command, 150 in the last 90 days, 45 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 7 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 52 °F - Altimeter: 30.00 inHg - Observed at: MRB, 10 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 19940531046979A](https://openairdocs.org/incident/19940531046979A), May 31, 1994: Bell TH13T, Friendsville, MD, Destroyed. REP0RT power loss on spray run. Too low and slow for autorotation. Struck trees. Engine running after crash. 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.