# NTSB ERA24LA299: Bellanca 8GCBC, N749SK, Frankford, DE, July 4, 2024 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: July 4, 2024, 16:00 local (20:00 UTC) - Place: Frankford, DE - Coordinates: 38.514252, -75.142126 - Nearby events: https://openairdocs.org/map.md?lat=38.5143&lon=-75.1421&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 194658 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA24LA299 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194658/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194658 - Page: https://openairdocs.org/ntsb/ERA24LA299 ## Probable cause A partial loss of engine power resulting from cylinder detonation and a cracked spark plug, which resulted in a forced landing and impact with terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Bellanca 8GCBC, 2 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=1220803), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Damaged/degraded (probable cause); cases with it: [Bellanca 8GCBC, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=1220803), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Bellanca 8GCBC, 2 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=1220803), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Bellanca 8GCBC, 14 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1220803), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was flying at 300 ft mean sea level (msl) while towing a banner when he noticed the engine oil temperature began to increase. The pilot informed the operator and climbed to 1,200 ft msl; however, the airplane would not maintain altitude and was slowly descending. The engine rpm began to decrease and the engine increasingly began to run rough. The pilot dropped the banner as the airplane descended through 700 ft msl, and he initiated a forced landing in a field that was bordered by trees. Unable to reach the field, the airplane impacted the top of trees. The airplane then descended to the ground, resulting in substantial airframe and wing damage. Postaccident examination of the engine revealed damage to the No. 3 cylinder that was consistent with detonation in the form of erosion on the edge of the intake valve and valve seat insert, and a cracked lower spark plug that was likely the cause of the detonation. A review of the most recent annual inspection maintenance logs revealed that the No. 3 cylinder assembly was replaced with a new cylinder 45 days before the accident. ## Factual narrative On July 4, 2024, at 1600 eastern daylight time, a Bellanca 8GCBC, N749SK was substantially damaged when it was involved in an accident near Frankford, Delaware. The commercial pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 banner towing flight. According to the pilot, the airplane was based at Bunting's Field Airport (4MD1), Berlin, Maryland. Before to the first flight of the day, the pilot added a quart of oil to the engine and completed a preflight inspection with no abnormalities noted. He also added fuel to the airplane and conducted an engine run-up that was normal. The pilot then departed and flew several aerial advertising banner flights throughout the day without incident, adding fuel as necessary. During the accident flight, with the banner in tow, he proceeded to fly from 4MD1 to the Ocean City, Maryland, inlet at 1,000 ft mean sea level (msl), then descended to 300 ft msl and flew north along the Rehoboth Beach coast during the advertising portion of the flight. The flight was uneventful, and all engine indications and airplane performance were normal and “in the green.” However, toward the end of the route, the engine oil temperature, which usually was about 190° F, indicated about 220° to 230° F. The pilot advised the operator of the higher-than-expected oil temperature and was informed by the operator that it was within limits as the outside air temperature was hot that day. As the pilot approached the end of the advertising portion of the flight, he initiated a climb to 1,200 ft msl; however, the airplane would not maintain altitude even though the throttle and mixture controls were full forward. The airplane was slowly descending, while the engine rpm was dropping with simultaneous engine roughness that was increasing in severity. The pilot elected to drop the banner over a vacant field as the airplane descended through 700 ft msl. As the airplane reached 500 ft msl, it exhibited a further reduction of engine power. The pilot intended to perform a forced landing to a field; however, the airplane was unable to reach the field, and the airplane impacted the top of trees. The airplane then descended to the ground inverted, which resulted in substantial damage to the wings and airframe. Examination of the airframe and engine revealed fuel and oil were present. The engine’s crankshaft was rotated via the propeller and crankshaft and valvetrain continuity were confirmed. There was compression on each of the cylinders. Erosion damage was noted on the edge of the No. 3 cylinder intake valve and valve seat insert, which also included a cracked lower spark plug. A review of the maintenance records revealed the that the No. 3 cylinder assembly was replaced with a new cylinder during the annual inspection 45 days before the accident. The airplane was subsequently signed off as airworthy. ## Aircraft - Registration: [N749SK](https://openairdocs.org/aircraft/N749SK), registered now, S/N 127-75, built 1974 (OpenAirDocs) - Reported make and model: BELLANCA 8GCBC - Registry model: [Bellanca 8GCBC](https://openairdocs.org/model/bellanca-8gcbc) (registry code 1220803) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 12775 - Year built: 1974 - Airframe hours: 9834 - Engines: Lycoming O-360 180 horsepower reciprocating - Damage: Substantial damage - Flight: Banner tow, Part 91 - Operator: Ocean Aerial Ads Inc - Registered owner: Ocean Aerial Ads Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 20, 2024, 200 hours before - Departed: 4MD1, Berlin, MD - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 24; injuries: minor; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: front; restraint: 4-point; flight hours: 407 total, 101 in this make and model, 264 as pilot in command, 129 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 7 knots, gusting 18 - Temperature: 81 °F, dew point 72 °F - Altimeter: 29.95 inHg - Observed at: OXB, 12 nm away - METAR: METAR KOXB 041853Z AUTO 19007G18KT 10SM CLR 27/22 A2995 RMK AO2 SLP140 T02670217= ## 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 20240704008739A](https://openairdocs.org/incident/20240704008739A), Jul 4, 2024: Bellanca 8GCBC, Frankford, DE, Substantial damage. Single airman was conducting banner tow opeations and was returning back to base, located at bunting's field (4MD1). The airman started to lose rpm's and could… ## Docket (6 files) The files NTSB released with the investigation on April 1, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194658. 9.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 8 pages, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17987361&FileExtension=pdf&FileName=Operators%206120%20Accident%20Report_N749SK-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 2, PDF, 1 page, 132 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18000919&FileExtension=pdf&FileName=Record%20of%20Conversation_Pilot_Redacted-Rel.pdf - FAA pilot's statement (item 3, PDF, 2 pages, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17987852&FileExtension=pdf&FileName=Pilots%20Statement_Redacted-Rel.pdf - Memorandum for record a�� FAA and mechanic examination (item 4, PDF, 1 page, 97 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17988716&FileExtension=pdf&FileName=FAA%20and%20Mechanic%20Examination_Redacted-Rel.pdf - Maintenance records_excerpt (item 5, PDF, 2 pages, 4.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17988580&FileExtension=pdf&FileName=Maintenance%20Logbook%20Excerpt_Redacted-Rel.pdf - Photos_accident site and airplane damage (item 6, PDF, 3 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18001755&FileExtension=pdf&FileName=Accident%20Site%20and%20Damage%20Photographs_N749SK-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.