# NTSB FTW89FA078: MBB BK-117A-4, N120HH, Houston, TX, April 9, 1989 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Field investigation · Final report - Date: April 9, 1989, 06:49 local (11:49 UTC) - Place: Houston, TX - Coordinates: 29.710004, -95.399497 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.7100&lon=-95.3995&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 3 serious - Status: Completed, report September 5, 1991 - Report: Approved by Office Director - NTSB case key (mKey): 22766 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW89FA078 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22766/pdf - Page: https://openairdocs.org/ntsb/FTW89FA078 ## Probable cause FAILURE OF THE PILOT TO MAINTAIN CLEARANCE FROM THE OBSTRUCTION (GARAGE). FACTORS RELATED TO THE ACCIDENT WERE: DARKNESS, ADVERSE WEATHER CONDITIONS, PERSONNEL IN THE AREA OF THE TEMPORARY HELIPORT, LACK OF SECURITY PROVIDED BY HOSPITAL MANAGEMENT, WHICH RESULTED IN A NECESSITY FOR THE PLT TO DIVERT HIS ATTENTION, AND THE PILOT'S LACK OF VISUAL QUES. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, takeoff - initial climb - light condition - dark night (contributing factor) - vertical takeoff - initiated, pilot in command - weather condition - drizzle/mist (contributing factor) - weather condition - unfavorable wind (contributing factor) - weather condition - turbulence (contributing factor) - object - other person (contributing factor) - security - inadequate, company/operator management (contributing factor) - diverted attention, pilot in command - object - building(nonresidential) (contributing factor) - clearance - not maintained, pilot in command (cause) - visual/aural detection, pilot in command (contributing factor) - Loss of control - in flight, takeoff - initial climb - rotor system,tail rotor blade - overload - directional control - not possible - In flight collision with terrain/water, descent - uncontrolled ## Analysis THE HELICOPTER WAS BEING OPERD FM A TEMPORARY LNDG ZONE (LZ) IN A PARKING LOT, WHILE THE HOSPITAL HELIPORT WAS BEING RESURFACED. AS THE PLT WAS PREPARING TO TAKEOFF AT NGT TO GET A PATIENT AT ANOTHER LCTN, HE NOTED PSNL IN THE AREA OF THE LZ & ADZD THE DISPATCHER OF THE LACK OF SECURITY. AT THAT TIME, THE WX (10 MI EAST AT HOUSTON HOBBY ARPT) WAS IN PART: 900' OVC, VIS 8 MI WITH LIGHT DRIZZLE, WIND FM 040 DEG AT 14 KTS. THE PLT BGN A VERTICAL TAKEOFF TO CLR OBSTACLES.HE RPRTD THAT AFTER LIFT-OFF, THE HELICOPTER ENCTRD TURBC & A VENTURI EFFECT FM WIND BLOWING AROUND THE BUILDINGS. ALSO,HE INDCD THAT HIS VISUAL QUES WERE REDUCED AS HE WAS WAS WATCHING FOR PEOPLE IN THE AREA OF THE LZ. AT ABOUT THAT TIME, WITNESSES OBSERVED THE HELICOPTER DRIFT BACKWARD. SUBSEQUENTLY, THE TAIL ROTOR CONTACTED THE TOP OF A GARAGE, THEN THE HELICOPTER BGN AN UNCTLD SPIN & CRASHED. THE PLT & BOTH MEDICAL CREW MEMBERS WERE SERIOUSLY INJURED. ## Aircraft - Registration: [N120HH](https://openairdocs.org/deregistered/N120HH-1991-03-25), registration cancelled 1991-03-25, S/N 7132 (OpenAirDocs) - Reported make and model: MBB BK-117A-4 - Registry model: [Messerschmitt-Bolkow-Blohm BK 117 A-4](https://openairdocs.org/model/messerschmitt-bolkow-blohm-bk-117-a-4) (registry code 5626017) (OpenAirDocs) - Category: Helicopter - Serial number: 7132 - Airframe hours: 529 - Engines: LYCOMING LTS 101-650B 650 horsepower turbo shaft - Damage: Destroyed - Flight: Positioning, Part 91 - Operator: Hermann Trust, doing business as Hermann Life Flight - Registered owner: Bell Atlantic Tricon - Airworthiness certificate: Standard, Transport - Last inspection: 100 hour, March 29, 1989, 46 hours before - Departed: NONE - Destination: NONE, CHANNELVIEW, TX - Flight plan: Company VFR - Airport: Hermann Hospital ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 40; commercial, private; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: right; toxicology performed; flight hours: 8,700 total, 1,590 in this make and model, 8,380 as pilot in command, 72 in the last 90 days, 17 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Night/dark - Wind: 40° at 14 knots - Visibility: 8 statute miles - Lowest ceiling: 900 ft overcast - Temperature: 57 °F, dew point 54 °F - Altimeter: 29.00 inHg - Observed at: HOU, 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 19890409006799A](https://openairdocs.org/incident/19890409006799A), Apr 9, 1989: Bolkms BK117A4, Houston, TX, Destroyed. Tail rotor struck side of building while drifting backwards on vertical takeoff. Began spinning. Dropped to pad. 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.