Wednesday, August 23, 2017

Smoke (Non-Impact): Enstrom F-28F Falcon, N52PD; incident occurred August 22, 2017 at Glendale Municipal Airport (KGEU), Maricopa County, Arizona

The National Transportation Safety Board did not travel to the scene of this incident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Scottsdale, Arizona

Aviation Incident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf


Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms


Aviation Incident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf 
 
http://registry.faa.gov/N52PD


Location: Glendale, AZ
Incident Number: WPR17IA198
Date & Time: 08/22/2017, 0904 MST
Registration: N52PD
Aircraft: ENSTROM F 28F
Aircraft Damage: None
Defining Event: Fire/smoke (non-impact)
Injuries: 2 None
Flight Conducted Under: Part 91: General Aviation - Instructional 
Analysis 

The flight instructor and student pilot were practicing hovering autorotations when the cockpit filled with smoke. The helicopter had just touched down, so the flight instructor secured the cockpit and both he and the student egressed the helicopter with the engine still running. About 5 minutes later, the engine stopped.

Postincident examination of the helicopter revealed no fire or other related damage. Maintenance personnel reported that the smoke appeared to have originated from the failure of an internal oil seal within the turbocharger-compressor that leaked oil into the turbocharger-compressor's exhaust system. No further examination or repair was accomplished and the turbocharger was replaced.

Further examination revealed damage to the turbocharger-compressor v-clamp assembly that was installed on the exhaust. The strap portion of the v-clamp assembly contained cracks on the outer face that emanated from three of the four spot welds. The edge of the strap portion exhibited evidence of bending deformation on both sides of the assembly. In the deformed areas, the distance between the edge of the retainer and the edge of the strap was smaller when compared to other, non-deformed areas. Further, microscopic examination of the largest crack revealed a fatigue crack emanating from the outer surface of the v-clamp assembly strap. It is likely that the v-clamp assembly bolts were tightened to an extent that caused the deformation in the strap. The damage found to the v-clamp was not related to the source of the smoke.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this incident to be:
An internal failure of the turbo-compressor, which resulted in oil leaking into the turbo-compressor's exhaust. 

Findings

Aircraft
Turbocharger - Malfunction (Cause)
Turbocharging (recip only) - Fatigue/wear/corrosion

Factual Information

On August 22, 2017, about 0904 mountain standard time, an Enstrom F-28F helicopter, N52PD, experienced smoke coming from the engine cowling area after touchdown at the Glendale Municipal Airport (GEU) Glendale, Arizona. The certified flight instructor and student pilot were not injured, and the helicopter was not damaged. The helicopter was registered to and operated by Airwest Aviation Academy LLC under the provisions of Title 14 Code of Federal Regulations Part 91, as an instructional flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The local flight departed GEU about 0820.

The flight instructor reported that at the time of the incident, the student was practicing hovering autorotations. Several had been accomplished without incident. During the last one, the engine appeared to have stalled, but sounded as if it were running rough when the cockpit filled with smoke. The helicopter was on the ground and the flight instructor secured the cockpit and both he and the student evacuated the helicopter with the engine still running and smoke coming out of the right side air scoop. About five minutes later, the engine stopped running.

Postincident examination of the helicopter revealed that no fire or other related damage was present. Maintenance personnel reported that the source of the smoke appeared to have originated from the failure of an internal oil seal within the turbocharger-compressor that leaked oil into the turbocharger-compressor's exhaust system. No further examination or repair was accomplished and the turbocharger was replaced.

Further examination identified that the V-clamp assembly that was installed on the turbo-compressor exhaust was damaged. The V-clamp assembly was removed and sent to the National Transportation Safety Board Material Laboratory, Washington DC for further examination. The examination of the V-clamp assembly revealed that the strap portion of the assembly contained cracks on three of the four spot welds that emanated from the outer face of the strap. The edge of the strap portion exhibited evidence of bending deformation on both sides of the assembly. In the deformed areas, the distance between the edge of the retainer and the edge of the strap, were smaller when compared to other non-deformed areas. Microscopic examination of the longest crack revealed that a fatigue crack emanated from the outer surface of the strap. The damage to the V-clamp was unrelated to the source of the smoke. 

History of Flight

Autorotation
Fire/smoke (non-impact) (Defining event)

Landing
Fire/smoke (non-impact)

After landing
Engine shutdown

Flight Instructor Information

Certificate: Flight Instructor; Commercial; Private
Age: 43, Male
Airplane Rating(s): None
Seat Occupied: Right
Other Aircraft Rating(s): Helicopter
Restraint Used: 4-point
Instrument Rating(s): Helicopter
Second Pilot Present: Yes
Instructor Rating(s): Helicopter
Toxicology Performed: No
Medical Certification: Class 2 With Waivers/Limitations
Last FAA Medical Exam: 04/03/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 12/18/2015
Flight Time:  (Estimated) 1300 hours (Total, all aircraft), 1280 hours (Total, this make and model), 1220 hours (Pilot In Command, all aircraft), 90 hours (Last 90 days, all aircraft) 

Student Pilot Information

Certificate: Private; Student
Age: 40, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s):
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Without Waivers/Limitations
Last FAA Medical Exam: 12/13/2016
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:

Aircraft and Owner/Operator Information

Aircraft Make: ENSTROM
Registration: N52PD
Model/Series: F 28F
Aircraft Category: Helicopter
Year of Manufacture: 1996
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 807
Landing Gear Type: Skid
Seats: 2
Date/Type of Last Inspection: 07/06/2017, Annual
Certified Max Gross Wt.: 2600 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 6264.3 Hours as of last inspection
Engine Manufacturer: Lycoming
ELT: Not installed
Engine Model/Series: HIO-360-F1AD
Registered Owner: AIRWEST AVIATION ACADEMY LLC
Rated Power: 190 hp
Operator: AIRWEST AVIATION ACADEMY LLC
Operating Certificate(s) Held: None 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KGEU, 1071 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 0853 MST
Direction from Accident Site: 90°
Lowest Cloud Condition: Scattered / 15000 ft agl
Visibility:  10 Miles
Lowest Ceiling:
Visibility (RVR):
Wind Speed/Gusts: 4 knots /
Turbulence Type Forecast/Actual: /
Wind Direction: 20°
Turbulence Severity Forecast/Actual: /
Altimeter Setting: 29.98 inches Hg
Temperature/Dew Point: 33°C / 14°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: GLENDALE, AZ (GEU)
Type of Flight Plan Filed: None
Destination: GLENDALE, AZ (GEU)
Type of Clearance: VFR
Departure Time: 0820 MST
Type of Airspace: Class D

Airport Information

Airport: Glendale Municipal Airport (GEU)
Runway Surface Type: Unknown
Airport Elevation: 1071 ft
Runway Surface Condition: Unknown
Runway Used: N/A
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: Precautionary Landing

Wreckage and Impact Information

Crew Injuries: 2 None
Aircraft Damage: None
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 None
Latitude, Longitude:  33.526944, -112.295278 (est)

NTSB Identification: WPR17IA198
14 CFR Part 91: General Aviation
Incident occurred Tuesday, August 22, 2017 in Glendale, AZ
Aircraft: ENSTROM F 28F, registration: N52PD
Injuries: 2 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.

On August 22, 2017, about 0904 mountain standard time, an Enstrom F-28F helicopter, N52PD, experienced smoke emanating from the engine cowling area while the flight instructor and student pilot were practicing hovering auto-rotations at the Glendale Municipal Airport (GEU) Glendale, Arizona. The helicopter had just touched down and therefore an immediate engine shutdown was accomplished. The flight instructor and student pilot were not injured. The helicopter was not damaged. The helicopter was registered to and operated by Airwest Aviation Academy LLC as a 14 Code of Federal Regulations Part 91 instructional flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The local flight departed GEU about 0750.

The helicopter was recovered to a secure facility for further examination.

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