# NTSB ATL98LA100: Aerofab Lake LA-4-250, N1401P, Wise, NC, July 4, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 4, 1998, 11:00 local (15:00 UTC) - Place: Wise, NC - Location: 36.4865° N, 78.1708° W: Placed by OpenAirDocs: center of Wise, NC, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=36.4865&lon=-78.1708&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report February 15, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 43605 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL98LA100 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43605/pdf - Page: https://openairdocs.org/ntsb/ATL98LA100 ## Probable cause The pilot's improper turn during the takeoff that resulted in dragging the sponson. A factor was the rough water caused by the boat wake. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Dragged wing,rotor,pod,float or tail/skid, takeoff - terrain condition - water,rough (contributing factor) - water loop/swerve - inadvertent, pilot in command (cause) - visual lookout - inadequate, pilot in command (cause) - procedures/directives - improper, pilot in command (cause) - crosswind component - not understood, pilot in command (cause) - Occurrence ## Analysis The pilot reported that while attempting a water takeoff from Lake Gaston, in Halifax County, North Carolina, the airplane encountered a boat wake. A right turn was made to parallel the wake, resulting in dragging the right sponson, and a water loop ensued. The FAA Advisory Circular 61-21A-Flight Training Handbook discusses the forces that act on a seaplane during a crosswind takeoff. It states that the crosswind pushes the airplane sideways, acting along with the friction of the airplane on the water causing the airplane to weathervane into the wind. The turn is aggravated by the occurrence of centrifugal force. This is opposed by the water reaction on the hull and if strong enough and, in combination with the wind may cause the seaplane to tip, submerging the downwind float and causing the wing to strike the water. This is known as a 'water loop'. ## Factual narrative On July 4, 1998, about 1100 eastern daylight time, an Aerofab, Inc. Lake LA-4-250, N1401P, dragged the right wing during a water takeoff near Wise, North Carolina. The airplane was operated by the pilot/registered owner, under the provisions of Title 14 CFR Part 91, and visual flight rules. A flight plan was not filed for the personal flight. There were no injuries to the private pilot or to his passenger, and the airplane was substantially damaged. The pilot reported that while attempting a water takeoff from Lake Gaston, in Halifax County, North Carolina, the airplane encountered a boat wake. A right turn was made to parallel the waves, resulting in dragging the right sponson, and a water loop ensued. The FAA inspector stated that the pilot's initial notification of the occurrence described minor damage. Subsequently, the mechanic repairing the airplane reported that the outboard six feet, approximately, of the right wing requires rebuilding, a major repair. The FAA Advisory Circular 61-21A-Flight Training Handbook discusses the forces that act on a seaplane during a crosswind takeoff. It states that the crosswind pushes the airplane sideways, acting along with the friction of the airplane on the water causing the airplane to weathervane into the wind. The turn is aggravated by the occurrence of centrifugal force. This is opposed by the water reaction on the hull and if strong enough and, in combination with the wind may cause the seaplane to tip, submerging the downwind float and causing the wing to strike the water. This is known as a "water loop". The FAA Investigator stated in his report that the airman will receive additional water instruction prior to any additional water operations. ## Aircraft - Registration: [N1401P](https://openairdocs.org/deregistered/N1401P-2018-04-19), registration cancelled 2018-04-19, S/N 12, built 1984 (OpenAirDocs) - Reported make and model: Aerofab Inc. LAKE LA-4-250 (LAKE LA-4-) - Registry model: [Aerofab LAKE LA-4-250](https://openairdocs.org/model/aerofab-lake-la-4-250) (registry code 5110320) (OpenAirDocs) - Registry engine: [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series) (registry code 41530, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 12 - Airframe hours: 888 - Engines: Lycoming IO-540 250 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Phillip J. Clements - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 25, 1998, 50 hours before - Departed: NONE - Destination: N51, READINGTON, NJ ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 180 total, 43 in this make and model, 165 as pilot in command, 51 in the last 90 days, 16 in the last 30 days, 9 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 5 knots - Visibility: 6 statute miles - Lowest ceiling: 20,000 ft overcast - Temperature: 91 °F, dew point 21 °F - Altimeter: 30.00 inHg - Observed at: RDU, 55 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 19980704030769A](https://openairdocs.org/incident/19980704030769A), Jul 4, 1998: Conaer LA4250, Wise, NC, Substantial damage. (.4)The pilot reported that while attempting a water takeoff from Lake Gaston, in halifax county, north carolina, the airplane encountered a boat wake. A right… ## Other investigations on N1401P (1) 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 ERA15FA348](https://openairdocs.org/ntsb/ERA15FA348), Sep 9, 2015: Aerofab Lake LA-4-250 (N1401P), Somerset, NJ, destroyed, 1 fatal. Probable cause: The pilot's attempted 180-degree return to the runway immediately after takeoff in dark night conditions, which resulted in collision with trees and terrain. Also causal was the pilot's inadequate… 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.