# NTSB CEN15CA274: Enstrom F 28C, N51778, Romeoville, IL, June 14, 2015

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: June 14, 2015, 15:00 local (20:00 UTC)
- Place: Romeoville, IL
- Coordinates: 41.607223, -88.087501 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.6072&lon=-88.0875&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-landing roll: Abnormal runway contact](https://openairdocs.org/ntsb-events/090)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report July 8, 2015
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA West Chicago FSDO
- NTSB case key (mKey): 91384
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN15CA274
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91384/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91384
- Page: https://openairdocs.org/ntsb/CEN15CA274

## Probable cause

The certified flight instructor (CFI) did not maintain directional control during a downwind emergency running landing to soft muddy terrain, which resulted in a dynamic rollover. Contributing to the accident was the CFI's delayed or insufficient remedial action when the pilot receiving instruction did not control the rotor RPM during hovering flight.

## Findings

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

- [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=3300407), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md)
- [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=3300407), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md)
- [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=3300407), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md)
- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Not specified (probable cause); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=3300407), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)

## Sequence of events

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

- [Maneuvering-hover: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Enstrom F-28C, 3 cases](https://openairdocs.org/ntsb-events/900/sequence.md?model=3300407), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md)
- [Maneuvering-hover: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-events/060/sequence.md?model=3300407), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md)
- [Landing-landing roll: Abnormal runway contact](https://openairdocs.org/ntsb-events/090) (defining event); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-events/090/sequence.md?model=3300407), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md)
- [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Enstrom F-28C, 2 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=3300407), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md)
- [Landing-landing roll: Roll over](https://openairdocs.org/ntsb-events/097); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-events/097/sequence.md?model=3300407), [All aircraft, 261 cases](https://openairdocs.org/ntsb-events/097/sequence.md)
- [Post-impact: Cabin safety event](https://openairdocs.org/ntsb-events/110); cases with it: [Enstrom F-28C, 1 case](https://openairdocs.org/ntsb-events/110/sequence.md?model=3300407), [All aircraft, 151 cases](https://openairdocs.org/ntsb-events/110/sequence.md)

## Analysis

The certified flight instructor (CFI) was giving flight instruction in the piston engine powered helicopter to an experienced airplane pilot, who had a total of about 2 hours of helicopter flight experience. The pilot receiving instruction was hovering the helicopter while oriented into the wind and he allowed the rotor RPM to decrease. While the helicopter was turning to the left, the CFI took over control, but was unable to regain RPM. The helicopter continued to turn to the left and the CFI conducted a downwind emergency running landing to soft muddy turf. After a ground run of about 15 to 20 feet the helicopter began to turn to the right and skids of the helicopter dug into the soft turf. The helicopter rolled 90 degrees onto its left side and both main rotor blades impacted terrain. The helicopter sustained substantial damage to the main rotor system, transmission, tail rotor, tail boom and fuselage. The CFI reported that he had been too slow in taking remedial action. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The characteristics displayed by the helicopter were indicative of it encountering a dynamic rollover.

## Factual narrative

The certified flight instructor (CFI) was giving flight instruction in the piston engine powered helicopter to an experienced airplane pilot, who had a total of about 2 hours of helicopter flight experience. The pilot receiving instruction was hovering the helicopter while oriented into the wind and he allowed the rotor RPM to decrease. While the helicopter was turning to the left, the CFI took over control, but was unable to regain RPM. The helicopter continued to turn to the left and the CFI conducted a downwind emergency running landing to soft muddy turf. After a ground run of about 15 to 20 feet the helicopter began to turn to the right and skids of the helicopter dug into the soft turf. The helicopter rolled 90 degrees onto its left side and both main rotor blades impacted terrain. The helicopter sustained substantial damage to the main rotor system, transmission, tail rotor, tail boom and fuselage. The CFI reported that he had been too slow in taking remedial action. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

## Aircraft

- Registration: [N51778](https://openairdocs.org/aircraft/N51778), registered now, S/N 451-2 (OpenAirDocs)
- Reported make and model: ENSTROM F 28C
- Registry model: [Enstrom F-28C](https://openairdocs.org/model/enstrom-f-28c) (registry code 3300407) (OpenAirDocs)
- Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 451-2
- Year built: 1978
- Engines: Lycoming HIO-360 205 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Airworthiness certificate: Standard, Normal
- Departed: LOT, Romeoville, IL
- Destination: LOT, Romeoville, IL
- Airport: LOT, Lewis University, runway 27, 5,696 × 75 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Flight instructor; age 37; injuries: minor; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review November 13, 2014; seat: left; restraint: 4-point; flight hours: 840 total, 272 in this make and model, 739 as pilot in command, 27 in the last 90 days, 15 in the last 30 days, 3 in the last 24 hours
- Pilot; age 29; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review March 13, 2015; seat: right; restraint: 4-point; flight hours: 6,474 total, 2 in this make and model, 3,040 as pilot in command, 95 in the last 90 days, 46 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 11 knots, gusting 15
- Visibility: 10 statute miles
- Lowest ceiling: 2,700 ft broken
- Temperature: 82 °F, dew point 70 °F
- Altimeter: 29.92 inHg
- Observed at: KLOT

## 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 20150614009209A](https://openairdocs.org/incident/20150614009209A), Jun 14, 2015: Enstrom F-28C, Romeoville, IL, Substantial damage. Instructor with an airplane rated student returned from a local flight. Hovering was being taught. Student was performing pedal turns. At some point, the…

## Docket (1 files)

The files NTSB released with the investigation on July 1, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91384. 898 KB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 898 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40428784&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.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.

---
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.