# NTSB CEN11LA396: Grumman G164, N2LU, Oak Ridge, LA, May 27, 2011

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 27, 2011, 14:30 local (19:30 UTC)
- Place: Oak Ridge, LA
- Coordinates: 32.643054, -91.818611 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.6431&lon=-91.8186&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Defining event: [Maneuvering-low-alt flying: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed, report February 12, 2013
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA Baton Rouge FSDO
- NTSB case key (mKey): 80795
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA396
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80795/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80795
- Page: https://openairdocs.org/ntsb/CEN11LA396

## Probable cause

The flight instructor's failure to maintain adequate airspeed, which resulted in an aerodynamic stall and subsequent impact with trees.

## Findings

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

- [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 2 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=3979904), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md)
- [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 2 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=3979904), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md)
- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Damaged/degraded; cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=3979904), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)
- [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on operation; cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 1 case](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=3979904), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md)

## Sequence of events

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

- [Maneuvering-low-alt flying: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=3979904), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md)
- [Maneuvering-low-alt flying: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 3 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=3979904), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md)
- [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 8 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=3979904), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)
- [Post-impact: Evacuation](https://openairdocs.org/ntsb-events/460); cases with it: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B, 1 case](https://openairdocs.org/ntsb-events/460/sequence.md?model=3979904), [All aircraft, 103 cases](https://openairdocs.org/ntsb-events/460/sequence.md)

## Analysis

The flight instructor was demonstrating agricultural, low-altitude operations to the pilot. The instructor reported that he noticed a loss of engine power when making a turn; the airplane then descended and impacted the tops of several trees. The airplane fell nose first through the thick wooded canopy, coming to rest in the trees in a mostly nose-down attitude. The pilot reported that the instructor had been flying the airplane slowly while in wingover turns and that the stall light would regularly flicker on and off during the climbing turns. He added that the instructor did not increase the engine power setting before impact and that the airspeed was low immediately before the airplane impacted the trees. The instructor did not report using carburetor heat during his low-altitude operations but did report that he was operating at a reduced power setting. An examination of the airplane showed no preimpact mechanical malfunctions or failures that would have precluded normal operation. Although a carburetor icing probability chart indicated that an airplane operating in the ambient conditions at the time of the accident could expect a risk of carburetor icing while at cruise power and a serious risk of carburetor icing while at glide power, it is more likely that the airplane entered into an aerodynamic stall at an altitude too low for the pilot to recover based on the account given by the pilot.

## Factual narrative

On May 27, 2011, about 1430 central daylight time, a Grumman G-164A, single engine airplane, N2LU, was substantially damaged when it impacted trees near Oak Ridge, Louisiana. The airplane was registered to and operated by Barham Brothers, Inc. The certified flight instructor (CFI) and the pilot both sustained minor injuries. Visual meteorological conditions prevailed and a flight plan had been not filed for the 14 Code of Federal Regulations Part 137 agricultural training flight. The local flight had departed from Hooks Memorial Airport (M79), Rayville, Louisiana, about 1330. The CFI reported that he was flying the airplane at a low-altitude and was demonstrating a pass to the pilot. He had been flying about 80 to 90 mph during the low passes with the engine power set at 22 to 23 inches of manifold pressure. The CFI made a flat tear-drop turn to reenter the field when he noticed a loss of engine power and a slight loss of altitude. The CFI then leveled the wings to stop turning and to maintain altitude. The descent continued and the airplane impacted the tops of several trees. Forward movement briefly stopped and the airplane then fell nose first through the thick wooded canopy coming to rest in the trees in a mostly nose down attitude. The pilot reported that the CFI had been flying the airplane down to 60 mph while in wingover turns and that the stall light would regularly flicker on and off during the climbing turns. The pilot also reported that the CFI did not increase the engine power setting before impact and that the airspeed was 60 mph or less immediately before the airplane impacted the trees. The impact resulted in substantial damage to all four wings, the ailerons, the fuselage, and the empennage. The CFI did not report using carburetor heat during his low altitude operations, but did report that he was operating at a reduced power setting. According to a carburetor icing probability chart, an airplane operating in the ambient conditions at the time of the accident could expect a risk of carburetor icing while at cruise power, and a serious risk of carburetor icing while at glide power. The G-164A Pilot’s Handbook shows the power-off stall speed is about 67 mph, and the best rate of climb speed is 83 mph, when operating at 4,500 pounds on a standard day. The handbook also shows that a 50 percent power setting at that weight would require about 27.7 inches of manifold pressure which would yield a cruise speed of 99 mph. Before recovering the wreckage from the accident site the operator reported that they were able to successfully test run the engine. An examination of the airplane showed no preimpact mechanical malfunctions or failures that would have precluded normal operations.

## Aircraft

- Registration: [N2LU](https://openairdocs.org/aircraft/N2LU), registered now, S/N 595B (OpenAirDocs)
- Reported make and model: GRUMMAN G164 (A)
- Registry model: [Gulfstream-Schweizer A/C GULFSTREAM AM G-164B](https://openairdocs.org/model/gulfstream-schweizer-a-c-gulfstream-am-g-164b) (registry code 3979904) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 595B
- Airframe hours: 9750
- Engines: P&W R-985 450 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Barham Brothers Inc
- Registered owner: Barham Brothers Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, March 20, 2011, 80 hours before
- Departed: M79, Rayville, LA
- Destination: M79, Rayville, LA
- Airport: M79, John H Hooks Jr Memorial

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Flight instructor; age 53; injuries: minor; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review March 18, 2011; seat: front; flight hours: 820 total, 40 in this make and model, 745 as pilot in command, 150 in the last 90 days, 55 in the last 30 days, 5 in the last 24 hours
- Pilot; age 25; injuries: minor; private; airplane ratings: single-engine land, multi-engine land; medical: class 3, with waivers/limitations; last flight review December 28, 2010; seat: rear; flight hours: 240 total, 1 in this make and model, 150 as pilot in command, 82 in the last 90 days, 35 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 68 °F
- Altimeter: 29.87 inHg
- Observed at: KBQP, 6 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 20110527015879A](https://openairdocs.org/incident/20110527015879A), May 27, 2011: Gulfstream-Schweizer A/C Corp GULFSTREAM AM G-164B, Oak Ridge, LA, Substantial damage. While in turn over woods aircraft loss power, settled into trees.

## Other investigations on N2LU (2)

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 FTW01LA193](https://openairdocs.org/ntsb/FTW01LA193), Aug 28, 2001: Grumman G164B (N2LU), Rayville, LA, substantial damage. Probable cause: the partial failure of the magneto drive coupling while maneuvering, which resulted in a loss of engine power and a forced landing. A contributing factor to the accident was the lack of suitable…
- [NTSB FTW98LA058](https://openairdocs.org/ntsb/FTW98LA058), Nov 24, 1997: Gulfstream-Schweizer G-164B (N2LU), Lecompte, LA, substantial damage. Probable cause: a loose battery cover, due to improper installation by maintenance personnel, that became jammed with an elevator control rod and restricted the movement of the elevator control system, which…

## Docket (8 files)

The files NTSB released with the investigation on December 18, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80795. 4.4 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 712 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383091&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Crewmember Statement from Certified Flight Instructor (item 2, .PDF, 68 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383092&FileExtension=.PDF&FileName=Crewmember%20Statement%20from%20Certified%20Flight%20Instructor-Redacted.PDF
- Crewmember Statement from Second Pilot (item 3, .PDF, 30 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383095&FileExtension=.PDF&FileName=Crewmember%20Statement%20from%20Second%20Pilot-Master.PDF
- Record of Conversation With Operator (item 4, .PDF, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383191&FileExtension=.PDF&FileName=Record%20of%20Conversation%20With%20Operator-Master.PDF
- Map (item 5, .PDF, 104 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383150&FileExtension=.PDF&FileName=Map-Master.PDF
- Weather Summary (item 6, .PDF, 238 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383154&FileExtension=.PDF&FileName=Weather%20Summary-Master.PDF
- Photo - View of wreckage at the impact location (Operator's Photo) (item 7, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383133&FileExtension=.PDF&FileName=Photo%20-%20View%20of%20wreckage%20at%20the%20impact%20location%20%20(Operator%27s%20Photo)-Master.PDF
- G-164A Pilot's Handbook (item 8, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383390&FileExtension=.PDF&FileName=G-164A%20Pilot%27s%20Handbook-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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