# Accident 20170420004369A: Robinson Helicopter Company R44 II, Orlando, FL, April 20, 2017

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: April 20, 2017, 10:30 local time
- Place: Orlando, FL
- Airport: Orlando
- Damage: Substantial damage
- Phase of flight: Cruise/Level Flight
- Operating rules: General operating rules (Part 91)
- Location: 28.4500° N, 81.4706° W: From the FAA
- Nearby events: https://openairdocs.org/map.md?lat=28.4500&lon=-81.4706&mi=10
- Aircraft: N899GB, a cancelled registration (https://openairdocs.org/deregistered/N899GB-2019-10-31) (OpenAirDocs)
- Registry model: Robinson Helicopter R44 II (registry code 7640122, https://openairdocs.org/model/robinson-helicopter-r44-ii) (OpenAirDocs)
- Registry engine: Lycoming IO-540 series (registry code 41530, https://openairdocs.org/engine/lycoming-io-540-series) (OpenAirDocs)
- Reported make and model: ROBINSON HELICOPTER COMPANY R44 II
- Reported engine: LYCOMING IO-540 SER
- People aboard: 3
- Fatal injuries: 0
- Other injuries: 0
- Pilot certificates: Commercial pilot
- Pilot flight hours: 1,315 total, 1,093 in this make and model, 202 in the last 90 days
- NTSB investigation: [NTSB ERA17LA163](https://openairdocs.org/ntsb/ERA17LA163) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20170420004369A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

AIRCRAFT WAS FLYING SOUTHBOUND AT OR ABOUT 600 FEET. PILOT STATED HE HEARD A LOUD ?POP? THAT WAS ACCOMPANIED BY A YAW OF THE AIRCRAFT AND NOTICED VIBRATION AND OR ROUGHNESS OF THE ENGINE. THE ROTOR TACHOMETER GAUGE WAS INDICATING ZERO ROTOR RPM AND THE ENGINE TACHOMETER INDICATED BELOW 70%. PILOT ENTERED AUTOROTATION AND AT TOUCHDOWN AIRCRAFT ROLLED UP ON THE FORWARD SKIDS AND PILOT APPLIED AFT CYCLIC. MAIN ROTOR BLADES CONTACTED TAILBOOM AND CHOPPED THE BOOM OFF FORWARD OF THE TAILROTOR GEARBOX. POST-ACCIDENT INSPECTION REVEALED THE MAIN GEARBOX YOKE PART NUMBER C908-1 WAS MISSING ONE OF TWO MAGNETS. THE TWO FACTORY INSTALLED MAGNETS PROVIDE THE SIGNAL FOR THE MAIN ROTOR TACHOMETER AND THE LOSS OF A MAGNET FROM THIS YOKE WILL DISRUPT MAIN ROTOR RPM INDICATION IN THE COCKPIT OF THE HELICOPTER.

## The NTSB's investigation of this event (1)

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.

- [NTSB ERA17LA163](https://openairdocs.org/ntsb/ERA17LA163), Apr 20, 2017: Robinson R44 (N899GB), Orlando, FL, substantial damage. Probable cause: A partial failure of the helicopter's engine tachometer due to the separation of one of the magnet assemblies and engine roughness, which precipitated the pilot’s initiation of an off-airport…

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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