# NTSB GAA16LA056: Airbus EC135, N36RX, Apple Valley, CA, November 19, 2015

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 19, 2015, 11:50 local (19:50 UTC)
- Place: Apple Valley, CA
- Coordinates: 34.599166, -117.190551 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.5992&lon=-117.1906&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Airport occurrence](https://openairdocs.org/ntsb-events/070)
- Highest injury: No injuries
- Injuries: 5 uninjured
- Status: Completed, report November 29, 2016
- Report: Approved by Office Director
- NTSB office: General Aviation Accidents
- Parties: FAA Riverside FSDO
- NTSB case key (mKey): 92344
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA16LA056
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/92344/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=92344
- Page: https://openairdocs.org/ntsb/GAA16LA056

## Probable cause

The ingestion of a towel from an unsecured storage container at the landing site into the helicopter's fenestron during the landing.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Airport facilities/design: security](https://openairdocs.org/ntsb-findings/03017080): Environmental issues › Operating environment · Effect on equipment (probable cause); cases with it: [Eurocopter Deutschland EC 135 P2+, 1 case](https://openairdocs.org/ntsb-findings/03017080/cases.md?model=5620030), [All aircraft, 4 cases](https://openairdocs.org/ntsb-findings/03017080/cases.md)
- [Object/animal/substance: debris/dirt/foreign object](https://openairdocs.org/ntsb-findings/03022055): Environmental issues › Physical environment · Effect on equipment (probable cause); cases with it: [Eurocopter Deutschland EC 135 P2+, 2 cases](https://openairdocs.org/ntsb-findings/03022055/cases.md?model=5620030), [All aircraft, 101 cases](https://openairdocs.org/ntsb-findings/03022055/cases.md)
- [Tail rotor](https://openairdocs.org/ntsb-findings/01046400): Aircraft › Aircraft propeller/rotor · Failure; cases with it: [Eurocopter Deutschland EC 135 P2+, 3 cases](https://openairdocs.org/ntsb-findings/01046400/cases.md?model=5620030), [All aircraft, 23 cases](https://openairdocs.org/ntsb-findings/01046400/cases.md)
- [Tail rotor](https://openairdocs.org/ntsb-findings/01046400): Aircraft › Aircraft propeller/rotor · Damaged/degraded; cases with it: [Eurocopter Deutschland EC 135 P2+, 3 cases](https://openairdocs.org/ntsb-findings/01046400/cases.md?model=5620030), [All aircraft, 23 cases](https://openairdocs.org/ntsb-findings/01046400/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Prior to flight: Simulated/training event](https://openairdocs.org/ntsb-events/600); cases with it: [Eurocopter Deutschland EC 135 P2+, 1 case](https://openairdocs.org/ntsb-events/600/sequence.md?model=5620030), [All aircraft, 173 cases](https://openairdocs.org/ntsb-events/600/sequence.md)
- [Landing: Airport occurrence](https://openairdocs.org/ntsb-events/070) (defining event); cases with it: [Eurocopter Deutschland EC 135 P2+, 2 cases](https://openairdocs.org/ntsb-events/070/sequence.md?model=5620030), [All aircraft, 56 cases](https://openairdocs.org/ntsb-events/070/sequence.md)
- [Landing: Prop/jet/rotor blast/suction](https://openairdocs.org/ntsb-events/082); cases with it: [Eurocopter Deutschland EC 135 P2+, 2 cases](https://openairdocs.org/ntsb-events/082/sequence.md?model=5620030), [All aircraft, 44 cases](https://openairdocs.org/ntsb-events/082/sequence.md)
- [Landing: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330); cases with it: [Eurocopter Deutschland EC 135 P2+, 2 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=5620030), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)
- [Landing: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Eurocopter Deutschland EC 135 P2+, 3 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=5620030), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md)

## Analysis

According to the airline transport pilot, firefighting personnel were using the helicopter for training to simulate patient loading and unloading. The training consisted of multiple takeoffs and landings from the training center landing site. The pilot reported that, during the third landing, when the helicopter was between 2 and 3 ft above ground level, he felt it shudder unexpectedly. The pilot immediately landed and shut down the helicopter without further incident. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. A postflight examination revealed that a towel had been ingested into the fenestron, which resulted in substantial damage to the fenestron tail rotor blades, fenestron housing body, tailboom, and tail rotor drive shaft flex couplings. The pilot reported that the towel had migrated from an unsecured storage container near the landing site. The investigation revealed that, when the towel was ingested, the fenestron hub fairing detached from the hub body, which was then ingested by the fenestron tail rotor blades. The operator's director of maintenance reported that a postaccident examination revealed that all of the main rotor blades "received a small amount of [foreign object damage] FOD…at middle cord line near the tips" and that the "damage was the result of FOD from the Fenestron [hub fairing ingestion] after the towel was ingested." This evidence indicates that the hub fairing body becoming detached due to the ingestion of the towel contributed to the severity of the damage.

## Factual narrative

On November 19, 2015, about 1150 Pacific standard time, an air ambulance Airbus EC-135P2+ helicopter, ingested foreign object debris (FOD) into the Fenestron during an approach to the Victor Valley College Regional Public Safety Training Center in Apple Valley, California. The commercial pilot and four passengers were not injured, and the helicopter sustained substantial damage. The helicopter was registered to and operated by Reach Air Medical Services LLC, Santa Rosa, California, under the provisions of 14 Code of Federal Regulations Part 135 as a day, visual flight rules passenger flight. Visual meteorological conditions prevailed and a company visual flight rules flight plan was filed. The flight originated from the Victor Valley College Regional Public Safety Training Center in Apple Valley, California. Note: Various photos and diagrams of the Airbus EC-135 Fenestron, including labeling of the various parts, is located in the public docket of this accident under the Airbus EC-135 Fenestron Hub Fairing Report. According to the pilot, the helicopter was being utilized for training with firefighting personnel to simulate patient loading and unloading. The training consisted of multiple takeoffs and landings from the training center landing site. He reported that during the third landing, between two to three feet above ground level, he felt the helicopter "shutter unexpectedly." The pilot immediately landed and shut down the helicopter without further incident. A postflight inspection revealed that a towel had been ingested into the Fenestron. The pilot reported that the towel migrated from an unsecured storage container near the landing site. The helicopter sustained substantial damage to the Fenestron tail rotor blades, the Fenestron housing body, the tail boom, and the tail rotor drive shaft flex couplings. During the course of the investigation, it was discovered that when the towel was ingested, the Fenestron hub fairing detached from the hub body and it was ingested by the Fenestron tail rotor blades. The director of maintenance (DOM) for the operator reported that the tail rotor gearbox was shipped to the manufacturer for an inspection. Additionally, the DOM reported that all of the main rotor blades, "received a small amount of FOD damage at middle cord line near the tips" and that the "damage was the result of FOD from the Fenestron [hub fairing ingestion] after the towel was ingested." The pilot reported there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. WRECKAGE AND IMPACT INFORMATION Photos supplied by the operator showed pieces of the towel attached to various stators in the Fenestron housing body. Large gouges in the Fenestron housing body were present, consistent with impact from FOD. Small gouges were also present on the various Fenestron tail rotor blades, consistent with impact from FOD. The Fenestron hub fairing was not attached in the photos. Aphoto of the Fenestron hub fairing displayed it in numerous pieces, consistent with being destroyed by the impact of the Fenestron tail rotor blades. ADDITIONAL INFORMATION Safety Recommendation NORW-2007-073 In 2007, the Accident Investigation Board Norway (AIBN) along with the European Aviation Safety Agency (EASA) filed a formal safety recommendation to Eurocopter (Airbus) regarding the design of the Fenestron hub fairing. This safety recommendation was based on an Airbus EC-135 accident (2007/35) that occurred in Liagardene, Norway in 2006, which sustained similar damage due to similar accident sequence events. This safety recommendation from the AIBN states in part; The accident has revealed that the hub cover of the Fenestron on EC-135 can loosen when the rotor tips are bent out. A loosened cover will be sucked through the Fenestron and cause extensive damage. AIBN recommends that Eurocopter consider whether the fixing mechanism between the cover and hub could be changed to prevent loosening. The response from EASA states in part; EASA agrees with this recommendation. Eurocopter Deutschland (ECD) has launched a technical review of possible design improvements to the Fenestron hub cap installation; this might lead to a future design change if deemed suitable. However, no unsafe design features have been identified so far. In-flight loss (as well as all other three events reported to ECD) was accompanied by contact of the Fenestron/tail boom with obstacles. This safety recommendation was closed out with no further action. After multiple requests, the manufacturer did not respond to inquiries from the National Transportation Safety Board investigator-in-charge concerning what actions have been taken regarding the inadequate design of the Fenestron hub fairing attachment. Airbus EC-135 Fenestron Hub Fairing Information The Fenestron hub fairing is attached to the hub body with six attachment hardware assemblies. These hardware assemblies are inserted inside of a lip in the hub body, which covers the entire hub body. Once the hardware assemblies are inserted inside of the lip in the hub body, the screws are then tightened by a mechanic. A bore is located at the center of the fairing to aid with detachment, and is sealed with a plastic plug. Various photos, diagrams, and historical Airbus Fenestron FOD ingestion accident/incident information is located in the public docket of this accident under the Airbus EC-135 Fenestron Hub Fairing Report.

## Aircraft

- Registration: [N36RX](https://openairdocs.org/aircraft/N36RX), registered now, S/N 0859, built 2009 (OpenAirDocs)
- Reported make and model: AIRBUS EC135 (P2+)
- Registry model: [Eurocopter Deutschland EC 135 P2+](https://openairdocs.org/model/eurocopter-deutschland-ec-135-p2-plus) (registry code 5620030) (OpenAirDocs)
- Registry engine: [Pratt & Whitney Canada PW206B2](https://openairdocs.org/engine/pratt-whitney-canada-pw206b2) (registry code 52288, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 0859
- Year built: 2009
- Airframe hours: 2812
- Engines: Pratt and Whitney PW206B2 447 horsepower turbo shaft; Pratt and Whitney PW206B2 447 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Operator: Reach Air Medical Services, LLC
- Registered owner: Reach Air Medical Services, LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, October 22, 2015
- Departed: Apple Valley, CA
- Destination: Apple Valley, CA
- Flight plan: Company VFR
- Equipment: Satellite tracking device, Electronic multifunction display, Auto-pilot

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 64; injuries: none; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 2, with waivers/limitations; last flight review October 2, 2015; seat: front; restraint: 4-point; flight hours: 17,000 total, 580 in this make and model, 8,500 as pilot in command, 64 in the last 90 days, 33 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 66 °F, dew point 21 °F
- Altimeter: 30.12 inHg
- Observed at: KVCV, 10 nm away

## Docket (6 files)

The files NTSB released with the investigation on March 10, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=92344. 3.8 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437649&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF
- Accident Photos (Courtesy of Operator) (item 2, .PDF, 6 photos, 536 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437651&FileExtension=.PDF&FileName=Accident%20Photos%20(Courtesy%20of%20Operator)-Master.PDF
- Pilot's Statement (item 3, .PDF, 164 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437652&FileExtension=.PDF&FileName=Pilot%27s%20Statement-Master.PDF
- Director of Maintenance's Statement (item 4, .PDF, 188 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437653&FileExtension=.PDF&FileName=Director%20of%20Maintenance%27s%20Statement-Master.PDF
- Accident Investigation Board Norway Report 2007/35 (item 5, .PDF, 266 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437654&FileExtension=.PDF&FileName=Accident%20Investigation%20Board%20Norway%20Report%202007%2F35-Master.PDF
- EASA Safety Recommendation NORW-2007-73 (item 6, .PDF, 72 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437655&FileExtension=.PDF&FileName=EASA%20Safety%20Recommendation%20NORW-2007-73-Master.PDF

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.

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