# NTSB CHI94GA038: Hughes 369HS, N9179F, Antonia, MO, November 19, 1993 - Type: NTSB accident investigation - Classification: Accident · Fatal · Final report - Date: November 19, 1993, 03:46 local (09:46 UTC) - Place: Antonia, MO - Coordinates: 38.359539, -90.370544 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.3595&lon=-90.3705&mi=10 - Highest injury: Fatal - Injuries: 1 fatal, 1 serious - Status: Completed, report September 27, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 9395 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI94GA038 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9395/pdf - Page: https://openairdocs.org/ntsb/CHI94GA038 ## Probable cause THE PILOT'S FAILURE TO MAINTAIN PROPER ALTITUDE. A FACTOR WAS THE DARK NIGHT. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, maneuvering - light condition - dark night (contributing factor) - proper altitude - not maintained, pilot in command (cause) - object - tree(s) ## Analysis WHILE MANEUVERING DURING A NIGHT FLIR TRAINING OPERATION, THE HELICOPTER DESCENDED BELOW THE PLANNED MANEUVERING ALTITUDE AND INADVERTENTLY CONTACTED THE TERRAIN. WITNESSES DESCRIBED THE PILOT'S REACTION TO THE INADVERTENT TOUCHDOWN AS AN ABRUPT RECOVERY WITH A STEEP RIGHT TURN INTO TREES. THE HELICOPTER THEN ROLLED INVERTED AND IMPACTED THE TERRAIN. NO MECHANICAL FAILURE/MALFUNCTION OF THE AIRFRAME, POWERPLANT, OR FLIGHT CONTROLS WAS FOUND. ## Factual narrative HISTORY OF FLIGHT On November 19, 1993, at 0346 central standard time, a Hughes 369HS, N9179F, operated as a public use aircraft by the Drug Enforcement Administration (DEA), impacted trees and terrain while on a training mission near Antonia, Missouri. The pilot sustained serious injuries and the passenger (observer) received fatal injuries. The helicopter sustained substantial damage. The 14 CFR Part 91 flight was operating in visual meteorological conditions. No flight plan was on file. The local flight departed Spirit of St. Louis Airport, at St. Louis, Missouri, at 0130. The purpose of the flight was for training using a Forward Looking Infrared (FLIR) system. Persons involved in the training were the DEA pilot, and the Missouri State Police observer to operate the FLIR system in the helicopter; two DEA agents and one Missouri State Policeman, on the ground. The pre-arranged plan was to have the two DEA agents and the policeman travel to a pre-selected location by motor vehicle and the helicopter to follow and maintain an altitude of approximately 1,500 feet above ground level (agl). After arriving at the location, the FLIR operator was to locate one of the individuals on the ground and follow him to a private residence while remaining at the pre-arranged altitude. The operation was to take place under the cover of darkness. There was no plan to land the helicopter at the location. Two way radio communication was maintained between the helicopter and the DEA agents on the ground. During the night of the operation, one landing at an athletic field was conducted to make a repair to the FLIR system. The mission was aborted at another location when the FLIR operator was unable to identify the residence selected. A decision was made at that time to proceed to another location. The DEA agents and the policeman arrived at the pre-selected location at 0344. The two DEA agents remained at the motor vehicle. The policeman began to approach the residence, walking west on a road. Both of the DEA agents indicated in their statements, that as the policeman was making his way west toward the residence they became aware that the helicopter was descending. The agents observations of the helicopter were based on their observance of the navigation lights on the helicopter and noises they heard during the event. They reported that the helicopter missed striking the policeman on the road by approximately 10 feet. The helicopter then touched down in an open field ringed by trees south of the road where the policeman was walking and west of where the agents were situated. The DEA agents stated that the helicopter was observed to touch down on the rear of the skids first, flatten out, and skid forward. Both DEA agents stated that the helicopter then lifted off and continued south. One DEA agent stated that as the helicopter began to gain altitude, he heard a noise which he believed to be the main rotor hitting something. The DEA agents then observed the helicopter continue south approximately 50 to 75 yards and gain about 50 feet of altitude. They stated the helicopter initiated an abrupt right turn and the noise of the main rotor hitting trees became evident. They stated that the helicopter then rolled inverted and impacted the terrain. At no time did the witnesses observe the landing light to be illuminated on the helicopter, nor were there any radio transmissions heard from the helicopter. A radar plot of the accident helicopter's flight path, just prior to impact, indicated that the helicopter was maintaining between 1,200 and 1,300 feet mean sea level (msl), in the area of the impact site, coincident with the approximate time of the accident. A copy of the Recorded Radar Study compiled by the NTSB, Office of Research and Engineering is attached as an addendum to this report. (Note: From surface charts the approximate elevation of the accident site was 900 feet msl). OTHER DAMAGE Trees and foliage were damaged during the accident. PERSONAL INFORMATION The pilot held a commercial certificate for helicopters and single engine airplanes. He also held an airline transport certificate for multi-engine airplanes. He had a total pilot time of 3,091 hours in all types of aircraft, with 289 hours in rotorcraft, and 220 hours in the make and model of the accident helicopter at the time of the accident. He was the holder of a first class medical certificate issued on July 2, 1993, with no limitations. His most recent biennial flight review was received in this make and model of helicopter one month prior to the accident. AIRCRAFT INFORMATION The helicopter was a Hughes 369HS, N9179F, serial number 140554S. The helicopter had accumulated 4,154 hours time in service at the time of the accident. An annual inspection was conducted on November 12, 1993, and the helicopter had accumulated eight hours time in service since the inspection. The total time on the engine was the same as the airframe and had accumulated 678 hours since the last overhaul. WRECKAGE AND IMPACT INFORMATION Marks corresponding with the size of the landing skids were found at the location described by witnesses to be the initial touchdown point on a heading of 185 degrees. These marks corresponded to a level attitude on terrain sloping forward and to the right approximately 10 to 15 degrees. The ground scars ended within about 15 feet. Multiple small branches of a tree 20 feet beyond the initial ground scars, 10 feet above ground level, were severed. A tree which was seven inches in diameter and located 150 feet beyond the initial ground contact marks was severed about 25 feet above ground level. The tree had numerous scars on the east side of it. The helicopter came to rest inverted 15 feet beyond the tree, on a heading of 330 degrees. A continuity check of the flight control system (collective, cyclic, and directional) was completed with no pre-impact discrepancies noted. An inspection of the collective/throttle control linkage to the governor/fuel control system showed no evidence of damage. The helicopter was equipped with dual flight controls. Both systems were inspected. The left seat cyclic control stick was fractured at the base. The right directional control pedal for the left seat/pilot position was fractured. The right directional control pedal for the right seat position was fractured. Witness statements showed that the fracture was the result of efforts by fire/crash rescue team members to facilitate the rescue of the occupants. The directional control rod was fractured at fuselage station 219.0 where the tailboom separation occurred. The control rod remained attached to the tail rotor gearbox bellcrank and when moved, showed no damage or malfunction of the tail rotor pitch control system. The main rotor system (hub assembly) showed extensive damage with lead/lag excursions and excessive blade flapping. The hub assembly had impact marks consistent with main rotor blade strikes. The tail rotor system (hub assembly) had minor damage, in the form of small dents and scratches. On the airframe, the forward windscreen and framing were fractured and separated. The right cockpit door frame was crushed and bent. The right front seat pan was buckled from the right/forward to left/rear. The tailboom fractured at fuselage station 219.0, and was bent at the point of separation. According to witness statements, the engine was still operating after the helicopter came to rest. The exact power setting is unknown. They stated the engine was shut down by the local fire department when they dispensed a fire suppressing agent into both exhausts. The drive system was examined. The over-running clutch functioned when inspected; rotating in one direction, while engaging when rotated in the opposite direction. The engine to transmission driveshaft showed no evidence of damage. The main rotor sys ## Aircraft - Registration: [N9179F](https://openairdocs.org/deregistered/N9179F-2015-04-30), registration cancelled 2015-04-30, S/N 140554S, built 1974 (OpenAirDocs) - Reported make and model: HUGHES 369HS - Registry model: [Hughes 369HS](https://openairdocs.org/model/hughes-369hs) (registry code 4470728) (OpenAirDocs) - Registry engine: [Allison 250 SER 400HP](https://openairdocs.org/engine/allison-250-ser-400hp) (registry code 03013, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 140554S - Airframe hours: 4154 - Engines: ALLISON 250-C20 400 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft, Part 91 - Operator: Drug Enforcement Admin. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 12, 1993, 8 hours before - Departed: SUS, ST. LOUIS, MO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 3,091 total, 220 in this make and model, 2,461 as pilot in command, 125 in the last 90 days, 32 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 180° at 10 knots, gusting 17 - Visibility: 7 statute miles - Lowest ceiling: 1,400 ft broken - Temperature: 45 °F, dew point 41 °F - Altimeter: 29.00 inHg - Observed at: SUS, 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 19931119043709A](https://openairdocs.org/incident/19931119043709A), Nov 19, 1993: Hughes 369HS, Antonia, MO, Substantial damage, 1 fatal. Observer was testing night vision goggles. Copter hit ground unplanned. Climbed. Impacted trees. No mechanical. 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.