IAD02LA059

NTSB accident investigation · Schleicher ASK21 · Woodstock, VA · June 16, 2002

Accident · Minor injuriesLimited investigationFinal report
Date
June 16, 2002, 15:45 local (19:45 UTC)
Place
Woodstock, VA
Injuries
2 minor
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N341KSSchleicher ASK21
Weather
Visual (VMC) · Day
Status
Completed · report August 26, 2003
Report
Approved by Office Director
Parties
FAA/FSDO
FAA report
20020616017729A
Case key
54984

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 failure to recognize the loss of orographic lift conditions. A factor was the loss of orographic lift.

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.

Loss of control - in flightManeuvering
Weather condition - otherFactor
Weather evaluation - inadequatePilot in commandCause
Stall/mush - inadvertentPilot in command
In flight collision with objectManeuvering
Object - tree(s)

Analysis

After being released from the tow plane, the pilot flew the glider for about 10 miles along a ridge. According to the pilot, he failed to recognize that the wind speed necessary to generate sufficient orographic lift had diminished, and also failed to execute a turn toward the valley while he had sufficient altitude to clear the terrain. As he executed a turn "into very weak ridge lift," the glider stalled, and mushed into trees. The pilot reported that his evaluation of the weather conditions prior to his departure predicted "good orographic lift" in the area. He also reported no mechanical deficiencies with the glider.

Factual narrative

On June 16, 2002, about 1545 eastern daylight time, a Schleicher ASK21 glider, N341KS, was substantially damaged when it impacted trees, then terrain, while maneuvering near Woodstock, Virginia. The certificated commercial pilot and the passenger received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the flight that departed the Front Royal-Warren County Airport (FRR), Front Royal, Virginia. The local personal flight was conducted under 14 CFR Part 91.

After he departed behind a tow airplane about 1530, the pilot flew toward the Massanutten Ridge. The glider was released from the tow airplane in the vicinity of Signal Knob, and flew about 10 miles along the ridge.

In a written statement, the pilot reported that while he was ridge soaring along Massanutten mountain, he "failed to recognize that the wind speed necessary to generate sufficient orographic lift had diminished." He also stated that he "failed to execute an alternate plan of turning toward the Shenandoah Valley, while he had enough altitude above the trees to safely make the turn."

The pilot reported that when he attempted to make the turn toward the valley, "into very weak ridge lift," the glider stalled and "mushed" into the trees. The glider slid through the trees, then impacted the ground in a nose low attitude.

The pilot also stated that he evaluated the weather conditions prior to his departure by visual observation, and talking to other pilots. He noted there was an overcast cloud layer about 4,000 feet, and the shadows from the clouds demonstrated there was "good orographic lift" in the area. The winds at the surface were from 270 degrees at 10 knots, and at the ridge top they were from 270 degrees about 15-20 knots.

The pilot reported approximately 445 hours of total flight experience, 186 of which, were in make and model. He also reported no mechanical deficiencies with the glider.

According to the pilot, the glider sustained substantial damage to both wings, the fuselage, and the horizontal stabilizer.

Weather reported at Winchester Regional Airport (OKV), Winchester, Virginia, 24 miles to the northeast, at 1540, included wind from 280 degrees at 12 knots, gusting to 17 knots, 10 miles visibility, and clear skies.

Aircraft

Registration
N341KS
Reported as
Schleicher ASK21
Category
Glider
Serial number
21252
Airframe hours
2,860
Engine
Damage
Substantial damage
Flight
Personal · Part 91
Operator
Frederic Winter
Registered owner
The K-21 Group
Airworthiness certificate
Standard, Normal
Last inspection
Annual · April 1, 2002 · 60 hours before
Departed
FRR · Front Royal, VA
Destination
FRR

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
55
Injuries
Minor
Certificate
Commercial
Last flight review
April 7, 2001
Seat
Rear
Flight hours
420 total · 186 in this make and model · 365 as pilot in command · 2 in the last 90 days · 2 in the last 30 days · 0 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
280° at 12 knots, gusting 17
Visibility
10 statute miles
Lowest ceiling
None
Temperature
79 °F, dew point 57 °F
Altimeter
29.78 inHg
Observed at
OKV, 24 nm away

Docket · 3

The files NTSB released with the investigation on June 24, 2003, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.2 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.