ATL98LA100

NTSB accident investigation · Aerofab Lake LA-4-250 · Wise, NC · July 4, 1998

Accident · No injuriesLimited investigationFinal report
Date
July 4, 1998, 11:00 local (15:00 UTC)
Place
Wise, NC
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Takeoff
Aircraft
N1401PAerofab Lake LA-4-250
Weather
Visual (VMC) · Day
Status
Completed · report February 15, 2001
Report
Approved by Office Director
FAA report
19980704030769A
Case key
43605

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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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

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Dragged wing,rotor,pod,float or tail/skidTakeoff
Terrain condition - water,roughFactor
Water loop/swerve - inadvertentPilot in commandCause
Visual lookout - inadequatePilot in commandCause
Procedures/directives - improperPilot in commandCause
Crosswind component - not understoodPilot in commandCause
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
Reported as
Aerofab Lake LA-4-250 (LAKE LA-4-)
Category
Airplane
Serial number
12
Airframe hours
888
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
45
Certificate
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.

Other investigations on N1401P · 1

Matched to the same aircraft by N-number and date.