# NTSB NYC00LA061: Zielke RV-4, N8ZZ, Florence, NJ, December 25, 1999 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: December 25, 1999, 14:00 local (19:00 UTC) - Place: Florence, NJ - Location: 40.1192° N, 74.8088° W: Placed by OpenAirDocs: center of Florence, NJ, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=40.1192&lon=-74.8088&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report August 13, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 48463 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC00LA061 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/48463/pdf - Page: https://openairdocs.org/ntsb/NYC00LA061 ## Probable cause Failure of one of the propeller blades. A factor was the necessity land across, rather than in alignment with, the furrowed terrain due to the nature of the emergency. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Propeller failure/malfunction, cruise - propeller system/accessories,blade - failure (cause) - Forced landing, emergency descent/landing - Gear collapsed, emergency landing - terrain condition - plowed/furrowed - proper alignment - not possible, pilot in command (contributing factor) ## Analysis About 30 minutes after takeoff, the pilot felt a 'buzz,' which lasted approximately 2 seconds. The airplane then shook violently, so the pilot retarded the throttle to reduce the shaking. He then turned the magnetos off, one at a time, and reapplied power, but the shaking returned with each power application. Carburetor heat was also applied, with no effect. The pilot then tried to add enough power to maintain altitude, but still found that its application resulted in violent shaking. Power was again reduced to keep the airplane controllable. The pilot attempted to guide the airplane to a nearby airport, but could not hold altitude, and headed for a plowed field. He tried to align the airplane with the furrows, but was unable to due to the approach angle. Upon touchdown, the landing gear collapsed, and the wing spars were damaged. During post-flight examination, part of one of the wooden propeller blades was found to be missing. There was no evidence of a bird strike. The propeller had been bolted onto the hub with the correct torque's, and the cowling had been found securely fastened to the airframe. The engine was also examined, with no significant anomalies noted, and there was no indication of airframe flutter. ## Factual narrative On December 25, 1999, about 1400 Eastern Standard Time, a homebuilt RV-4, N8ZZ, was substantially damaged during a forced landing in Florence, New Jersey. The certificated airline transport pilot received minor injuries, and visual meteorological conditions prevailed at the time of the accident. No flight plan had been filed for the local flight, from Northeast Philadelphia Airport (PNE), Philadelphia, Pennsylvania. The personal flight was conducted under 14 CFR Part 91. According to the pilot, the flight originated about 1330. Engine start, taxi, and engine run-up were all normal. About 30 minutes after takeoff, the pilot felt a "buzz," which lasted about 2 seconds. The airplane then shook violently, so the pilot retarded the throttle to reduce the shaking. He then turned the magnetos off, one at a time, and reapplied power, but the shaking returned with each power application. Carburetor heat was also applied, with no effect. The pilot then tried to add "enough power to hold altitude," but again found that its application resulted in violent shaking. "Rather than risk shaking [the airplane] apart," power was again reduced to keep the airplane controllable. The pilot attempted to guide the airplane to a nearby airport, but could not hold altitude, and headed towards a field. During the approach to the field, the vibration was so severe that the pilot had trouble seeing the airspeed indicator. Nearing the landing, the pilot reduced power, "to see what I was going to hit." The pilot saw that the field had been plowed, and attempted to align the airplane with the furrows, but couldn't due to the airplane's approach angle. Upon touchdown, the landing gear collapsed, and the wing spars were damaged. After the accident, the pilot found only one of the two wooden propeller blades. According to a Federal Aviation Administration inspector, after the airplane was removed from the accident site to a storage facility, one of the wooden propeller blades was missing. There was no evidence of a bird strike. The propeller had been bolted onto the hub with the correct torque's, and the cowling had been found securely fastened to the airframe. The engine was also examined, with no significant anomalies noted, and there was no indication of airframe flutter. The owner of the airplane stated that there were only 5 to 6 hours of flight time on the Aymar-Demuth propeller. "This prop was beefy - built to handle the torque." The propeller was the third one on the airplane, which was built in 1994. The owner had flown the airplane to Oshkosh in the summer of 1999, and while there, a crack had been found in one of the blades. The manufacturer shipped him a 160-horsepower-rated loaner propeller to get the airplane home, and once there, the 180-horsepower accident propeller was installed. The owner also noted that after every time the airplane was flown, he cleaned and polished the propeller, and that before the airplane took off on the day of the accident, it was "perfect." ## Aircraft - Registration: [N8ZZ](https://openairdocs.org/deregistered/N8ZZ-2013-07-30), registration cancelled 2013-07-30, S/N 3407, built 1994 (OpenAirDocs) - Reported make and model: Zielke RV-4 - Registry model: [Zielke Charles S RV-4](https://openairdocs.org/model/zielke-charles-s-rv-4) (registry code 05625FT) (OpenAirDocs) - Registry engine: [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d) (registry code 41504, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 3407 - Airframe hours: 230 - Engines: Lycoming O-360 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Louis I. Willig - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, April 1, 1999, 40 hours before - Departed: PNE, PHILADELPHIA, PA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 6,077 total, 70 in this make and model, 5,932 as pilot in command, 260 in the last 90 days, 81 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 25 °F, dew point 10 °F - Altimeter: 30.00 inHg - Observed at: TTN, 12 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 19991225047409A](https://openairdocs.org/incident/19991225047409A), Dec 25, 1999: Amtr RV4, Florence, NJ, Substantial damage. (.4) About 30 minutes after takeoff, the pilot felt a 'buzz,' which lasted approximately 2 seconds. The airplane then shook violently, so the pilot retarded… 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.