# NTSB ERA21LA284: Cessna 150, N8172S, Elba, AL, July 11, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: July 10, 2021, 20:10 local (Jul 11, 2021, 01:10 UTC) - Place: Elba, AL · wooded airport property near service road - Coordinates: 31.410042, -86.090336 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.4100&lon=-86.0903&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Fuel related](https://openairdocs.org/ntsb-events/190) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 103454 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA284 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103454/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103454 - Page: https://openairdocs.org/ntsb/ERA21LA284 ## Probable cause The partial loss of engine power due to the formation of carburetor ice, which resulted in reduced climb capability and impact with trees during takeoff. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuel system: fuel distribution](https://openairdocs.org/ntsb-findings/01022820): Aircraft › Aircraft systems · Capability exceeded (probable cause); cases with it: [Cessna 150F, 2 cases](https://openairdocs.org/ntsb-findings/01022820/cases.md?model=2071814), [All aircraft, 141 cases](https://openairdocs.org/ntsb-findings/01022820/cases.md) - [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 150F, 7 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=2071814), [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. - [Initial climb: Fuel related](https://openairdocs.org/ntsb-events/190) (defining event); cases with it: [Cessna 150F, 2 cases](https://openairdocs.org/ntsb-events/190/sequence.md?model=2071814), [All aircraft, 361 cases](https://openairdocs.org/ntsb-events/190/sequence.md) - [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Cessna 150F, 8 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2071814), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 150F, 14 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2071814), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 150F, 39 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2071814), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis After performing flight training maneuvers for about 30 minutes, the instructor and student returned to the airport to practice short/soft field takeoffs and landings. After the first full-stop landing, the flight instructor recalled applying carburetor heat during the landing and taxi back for the next takeoff. During the student’s subsequent short field takeoff, the airspeed did not increase as expected while in ground effect and the instructor asked the student why he was not climbing. The student replied that he didn’t know and relinquished the controls to the instructor. The instructor determined that the engine was not producing enough power to maintain level flight and that they were too low to troubleshoot. As the airplane descended and the airspeed decreased, she lowered the nose and made a forced landing into trees, which resulted in substantial damage to the wings and fuselage. After the accident the flight instructor stated she thought the cause was carburetor ice. The temperature and dewpoint at the time of the accident were conducive to serious icing at glide power, and carburetor ice likely accumulated during the approach and previous landing. Although the instructor recalled applying carburetor heat during taxi there may not have been sufficient time to melt all or any accumulated carburetor ice. ## Factual narrative On July 10, 2021, about 2010 central daylight time, a Cessna 150F, N8172S, was substantially damaged when it was involved in an accident near Elba, Alabama. The flight instructor and student pilot were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the flight instructor, after conducting maneuvers for about 30 minutes, they returned to Carl Folsom Airport (14J) to conduct short/soft field landings and takeoffs. After the first successful full-stop landing, they taxied back to the runway and set up for a short field takeoff and, according to the flight instructor, she applied carburetor heat during the short taxi. Shortly after rotation and liftoff, the airspeed was not increasing as they flew in ground effect. The flight instructor asked why they weren’t climbing, and the student stated, “I don’t know, you have the controls.” The flight instructor took the control of the airplane and performed a shallow right climbing turn to avoid the trees at the end of the runway. The flight instructor stated there was no time to perform any troubleshooting of the engine because they were “barely” flying, and she needed to “just fly the airplane.” The engine was operating but not producing sufficient power to maintain level flight. They were flying over the treetops as the airspeed continued to decrease and the airplane started to descend. The flight instructor pushed the nose over to avoid a stall and landed the airplane in the trees. The airplane wreckage was located about 1,000 ft west southwest of the departure end of the runway in heavy wooded terrain and brush. Postaccident examination of the wreckage by a Federal Aviation Administration (FAA) inspector revealed that the airplane came to rest in a nose-down attitude and was tilted to the right. Both wings were bent aft, and the airframe sustained substantial damage. The left fuel tank was breached, and the right tank remained intact and contained fuel. The inspector was unable to examine the engine due to the airplane’s orientation and surrounding terrain. After the accident, the instructor told the FAA inspector that she had been thinking about what caused the accident and stated she thought it might be carburetor icing. The wreckage was recovered to an aviation salvage company and promptly sold. According to the salvage company that took possession of the wreckage, the engine was in excellent working condition and was subsequently sold to a private individual. A review of the local area meteorological data showed that the 1958 recorded weather observation at Shell Army Heliport (SXS) Fort Novosel, Alabama, about 12 miles southeast of the accident location, included wind from 240° at 3 knots, 9 miles visibility, clear skies, temperature 24°C, dew point 22°C; and an altimeter setting of 30.08 inches of mercury. The carburetor icing probability chart from FAA Special Airworthiness Information Bulletin (SAIB): CE-09-35 CarburetorIcing Prevention, showed a probability of serious icing at glide power at the temperature and dew point reported at the time of the accident. FAA Special Airworthiness Information Bulletin (CE-09-35) – Carburetor Icing Prevention, stated that: …pilots should be aware that carburetor icing doesn't just occur in freezing conditions, it can occur at temperatures well above freezing temperatures when there is visible moisture or high humidity. Icing can occur in the carburetor at temperatures above freezing because vaporization of fuel, combined with the expansion of air as it flows through the carburetor, (Venturi Effect) causes sudden cooling, sometimes by a significant amount within a fraction of a second. Carburetor ice can be detected by a drop in rpm in fixed pitch propeller airplanes and a drop in manifold pressure in constant speed propeller airplanes. In both types, usually there will be a roughness in engine operation. ## Aircraft - Registration: [N8172S](https://openairdocs.org/deregistered/N8172S-2023-01-14), registration cancelled 2023-01-14, S/N 15061772, built 1965 (OpenAirDocs) - Reported make and model: CESSNA 150 (F) - Registry model: [Cessna 150F](https://openairdocs.org/model/cessna-150f) (registry code 2071814) (OpenAirDocs) - Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 15061772 - Year built: 1965 - Airframe hours: 4666.8 - Engines: Continental O-200 100 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 21, 2021, 4 hours before - Airport: 14J, Carl Folsom Airport, runway 19, 3,050 × 75 ft, asphalt - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 34; injuries: none; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: helicopter, airplane; medical: class 1, without waivers/limitations; last flight review December 6, 2020; seat: right; restraint: 4-point; flight hours: 1,330 total, 4 in this make and model, 1,100 as pilot in command, 130 in the last 90 days, 11 in the last 30 days, 4 in the last 24 hours - Student pilot; age 25; injuries: none; student; medical: class 2, without waivers/limitations; seat: left; restraint: 4-point; flight hours: 62 total, 6 in this make and model, 3 as pilot in command, 13 in the last 90 days, 1 in the last 30 days ## Weather - Conditions: Visual (VMC), Dusk - Wind: 240° at 3 knots - Visibility: 9 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 72 °F - Altimeter: 30.08 inHg - Observed at: SXS, 12 nm away - METAR: KSXS 110058Z AUTO 24003KT 9SM CLR 24/22 A3008 RMK AO2 SLP185 T02400219 ## 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 20210710010529A](https://openairdocs.org/incident/20210710010529A), Jul 10, 2021: Cessna 150F, Elba, AL, Destroyed. Aircraft departed runway 19 at 14J performing a soft field take off. Upon climb out, the aircraft began to lose power. The instructor took control and… ## Docket (8 files) The files NTSB released with the investigation on August 30, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103454. 15.9 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 5.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15062123&FileExtension=pdf&FileName=6120%20Accident%20Report_Redacted-Rel.pdf - Pilot statements (nstructor and student) (item 2, PDF, 2 pages, 4.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15062303&FileExtension=pdf&FileName=Pilot%20Statements_Redacted-Rel.pdf - FAA inspector's statement (item 3, PDF, 1 page, 324 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12636889&FileExtension=pdf&FileName=FAA%20Inspectors%20Statement-Rel.pdf - Record of conversation_instructor (item 4, PDF, 1 page, 111 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15732285&FileExtension=pdf&FileName=Record%20of%20Conversation_Instructor-Rel.pdf - Record of conversation_salvage company (item 5, PDF, 1 page, 108 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15730995&FileExtension=pdf&FileName=Record%20of%20Conversation_Wentworth-Rel.pdf - Maintenance records (excerpts) (item 6, PDF, 2 pages, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15731507&FileExtension=pdf&FileName=Maintenance%20Records%20Excerpt_Redacted-Rel.pdf - Photo array_accident site and airplane damage (item 7, PDF, 4 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15731889&FileExtension=pdf&FileName=Accident%20Site%20and%20Damage%20Photographs_N8172S-Rel.pdf - Carb icing chart (item 8, PDF, 1 page, 171 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15738113&FileExtension=pdf&FileName=Carb%20Icing%20Chart-Rel.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.