# NTSB CEN13LA525: Cessna 182, N6460A, Boulder, CO, September 1, 2013

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: September 1, 2013, 11:00 local (17:00 UTC)
- Place: Boulder, CO
- Coordinates: 39.908889, -105.117225 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.9089&lon=-105.1172&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern final: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report February 3, 2014
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: FAA -- Denver Flight Standards
- NTSB case key (mKey): 87974
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13LA525
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/87974/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=87974
- Page: https://openairdocs.org/ntsb/CEN13LA525

## Probable cause

The pilot's failure to adequately clear carburetor icing, resulting in a loss of engine power on final approach following a descent at idle power.

## Findings

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

- [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Cessna 182, 4 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=2072702), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md)
- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Inoperative (probable cause); cases with it: [Cessna 182, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=2072702), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)
- [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 182, 1 case](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=2072702), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md)

## Sequence of events

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

- [Approach-VFR pattern final: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 182, 5 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072702), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)
- [Emergency descent: Ditching](https://openairdocs.org/ntsb-events/441); cases with it: [Cessna 182, 1 case](https://openairdocs.org/ntsb-events/441/sequence.md?model=2072702), [All aircraft, 186 cases](https://openairdocs.org/ntsb-events/441/sequence.md)

## Analysis

The pilot reported that he had flown a group of skydivers to altitude for an intentional parachute jump about 3 miles north of the airport and was returning for landing at the time of the accident. The airplane was on final approach when the engine lost power. The pilot's attempts to restore engine power were unsuccessful, and he ditched the airplane into a lake short of the runway. The pilot reported using carburetor heat during the descent; however, the pilot did not periodically apply engine power (clear the engine) during the descent. According to FAA Advisory Circular 20-113, Pilot Precautions and Procedures to be Taken in Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems, "Heat should be applied for a short time to warm the induction system before beginning a prolonged descent with the engine throttled and left on during the descent. Power lever advancement should be performed periodically during descent to assure that power recovery can be achieved." A postaccident engine examination did not reveal any anomalies consistent with a preimpact failure or malfunction. Local weather conditions were conducive to the formation of carburetor icing.

## Factual narrative

**This report was modified on 1/30/2014. Please see the public docket for this accident to view the original report.** On September 1, 2013, about 1100 mountain daylight time, a Cessna 182 airplane, N6460A, was substantially damaged when the pilot ditched the airplane into a lake following a loss of engine power on approach to the Boulder Municipal Airport (BDU), Boulder, Colorado. The pilot sustained minor injuries. The airplane was registered to and operated by N6460A LLC under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight originated from BDU about 1035. The pilot reported that he had flown a group of skydivers to altitude for an intentional parachute jump about 3 miles north of the airport and was returning for landing at the time of the accident. The airplane was on final approach to runway 8 (4,100 feet by 75 feet, asphalt) when the engine lost power. His attempts to restore engine power were unsuccessful and he subsequently ditched into Hayden Lake short of the runway. He reported a clear sky with a light and variable wind. A postaccident engine examination conducted by a National Transportation Safety Board investigator did not reveal any anomalies consistent with a preimpact failure or malfunction. Approximately 11 gallons of fuel were recovered from the airplane after the accident. The Pilot's Operating Handbook for the accident airplane noted that up to 5 gallons of fuel is unusable in all flight conditions, with 2 gallons of fuel being unusable in level flight. Weather conditions recorded at the Rocky Mountain Metropolitan Airport (BJC), located about 9 miles southeast of BDU, at 1047, included an ambient temperature and dew point of 21 degrees Celsius and 11 degrees Celsius, respectively. According to a Federal Aviation Administration (FAA) inspector, the pilot had reported using carburetor heat during the descent after the skydivers left the airplane; however, the pilot did not periodically apply engine power (clear the engine) during the descent. Information provided by the FAA regarding carburetor icing noted a possibility of serious icing at glide power under those conditions. According to FAA Advisory Circular 20-113, Pilot Precautions and Procedures to be Taken in Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems, "Heat should be applied for a short time to warm the induction system before beginning a prolonged descent with the engine throttled and left on during the descent. Power lever advancement should be performed periodically during descent to assure that power recovery can be achieved."

## Aircraft

- Registration: [N6460A](https://openairdocs.org/deregistered/N6460A-2017-06-29), registration cancelled 2017-06-29, S/N 33260, built 1956 (OpenAirDocs)
- Reported make and model: CESSNA 182
- Registry model: [Cessna 182](https://openairdocs.org/model/cessna-182) (registry code 2072702) (OpenAirDocs)
- Registry engine: [Continental 0-470-4](https://openairdocs.org/engine/continental-0-470-4) (registry code 17368, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 33260
- Engines: CONT MOTOR O-470-4 225 horsepower reciprocating
- Damage: Substantial damage
- Flight: Skydiving, Part 91
- Operator: N6460a LLC
- Registered owner: N6460a LLC
- Airworthiness certificate: Standard, Normal
- Departed: BDU, Boulder, CO
- Destination: BDU, Boulder, CO
- Airport: BDU, Boulder Municipal, runway 08, 4,100 × 75 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 31; injuries: minor; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; seat: left; flight hours: 1,031 total, 747 in this make and model, 919 as pilot in command, 235 in the last 90 days, 87 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: 10,000 ft broken
- Temperature: 70 °F, dew point 52 °F
- Altimeter: 30.29 inHg
- Observed at: BJC, 9 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 20130901016439A](https://openairdocs.org/incident/20130901016439A), Sep 1, 2013: Cessna 182, Boulder, CO, Substantial damage. On sept.1st 2013 N6460A lost power on final approach to bdu airport and landed short of runway in hayden lake. Aircraft received substantial damage on…

## Docket (7 files)

The files NTSB released with the investigation on December 13, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=87974. 4.7 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40402535&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Summary of Engine Examination (item 2, .PDF, 104 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40402435&FileExtension=.PDF&FileName=Summary%20of%20Engine%20Examination-Master.PDF
- Weather Observations -- Rocky Mountain Metro Airport (KBJC) (item 3, .PDF, 24 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40402453&FileExtension=.PDF&FileName=Weather%20Observations%20--%20Rocky%20Mountain%20Metro%20Airport%20(KBJC)-Master.PDF
- FAA Information Bulletin -- Carburetor Icing (item 4, .PDF, 148 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40402451&FileExtension=.PDF&FileName=FAA%20Information%20Bulletin%20--%20Carburetor%20Icing-Master.PDF
- FAA Advisory Circular -- Engine Induction System Icing (item 5, .PDF, 545 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40408010&FileExtension=.PDF&FileName=FAA%20Advisory%20Circular%20--%20Engine%20Induction%20System%20Icing-Master.PDF
- POH Excerpt -- Fuel System (item 6, .PDF, 230 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40408005&FileExtension=.PDF&FileName=POH%20Excerpt%20--%20Fuel%20System-Master.PDF
- 1/30/2014 Factual Revisions (item 7, .PDF, 42 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40409293&FileExtension=.PDF&FileName=1%2F30%2F2014%20Factual%20Revisions-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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