LAX03CA201

NTSB accident investigation · Schleicher ASW-20 · Idyllwild, CA · June 15, 2003

Accident · Minor injuriesData collectionFinal report
Date
June 15, 2003, 15:00 local (22:00 UTC)
Place
Idyllwild, CA
Injuries
1 minor
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N34LBSchleicher ASW-20
Weather
Visual (VMC) · Day
Status
Completed · report September 30, 2003
Report
Approved by Office Director
Parties
FAA FSDO
FAA report
20030615011669A
Case key
57244

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 combined effects of a loss of thermal lift and a gust induced loss of airspeed at a low above ground altitude, which resulted in a descent to impact with trees. The pilot's failure to maintain an adequate terrain clearance margin while cruising in mountainous terrain was a factor.

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.

In flight collision with objectCruise
Weather condition - no thermal liftCause
Airspeed - not maintainedPilot in commandCause
Weather condition - gustsCause
Descent - initiatedPilot in command
Clearance - inadequatePilot in commandFactor
Terrain condition - mountainous/hilly
Object - tree(s)

Analysis

The glider impacted trees after a loss of thermal lift during gusty wind conditions. After the glider was released from the tow plane, the pilot made repeated attempts to ascend a mountain; however, insufficient thermals were found to accomplish the climb. On the third attempt, the airspeed suddenly went from 55 to 40 knots and the glider lost 100 to 200 feet. The pilot lowered the nose to prevent a stall. There was a dead tree to the left of the glider and the pilot executed a nose down, right turn downslope in order to maintain speed and regain terrain clearance. Shortly thereafter, the wings collided with trees and were sheared from the fuselage. The fuselage went through the two trees and came to rest inverted. The pilot stated that there were no control problems noted with the glider.

Factual narrative

On June 15, 2003, about 1500 Pacific daylight time, an unpowered Schleicher ASW-20 glider, N34LB, impacted trees after a loss of thermal lift near Idyllwild, California. The pilot/owner was operating the glider under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, sustained minor injuries; the glider sustained substantial damage. The personal local flight departed Hemet-Ryan Field (HMT), Hemet, California, about 1230. Day visual meteorological conditions prevailed, and no flight plan had been filed. The primary wreckage was at 33 degrees 44 minutes north latitude and 116 degrees 44 minutes west longitude.

The pilot reported he was released from the tow airplane near mountains, in gusty wind conditions, about 3,000 feet above ground level (agl), 4,500 feet mean sea level (msl). He climbed, using thermals, to 6,000 feet msl. The first goal was to ascend Mount San Jacinto (10,804 feet msl). The usual procedure to complete the ascension over the mountain range consisted of a "stepping stone" approach along or between the mountains. The pilot had done this maneuver on many past flights.

After a third attempt to ascend Mount San Jacinto, the pilot did not find lift, and cruised in a southeast direction at 6,400 feet msl and 55 knots. Suddenly, he felt the glider slow, and noticed his airspeed had dropped from 55 to 40 knots and the glider had lost 100 to 200 feet. The pilot lowered the nose to prevent a stall. There was a dead tree to the left of the glider so the pilot executed a right, nose down turn downslope in order to maintain speed and regain terrain clearance. He heard a "bang," then a series of "booms and shocks" as the glider hit trees. Thereafter, he lost control of the glider.

The glider went between two trees, spaced about 6 feet apart. The wings were sheared off and remained in the trees' branches, about 20 feet agl. The fuselage went between the two trees, and came to rest nose down, inverted, on the ground. The pilot worked his way out of the glider, and spent the night in the mountains. After an extensive hike, he followed a creek bed to a highway where he was later rescued. The pilot did not report any control malfunctions prior to the mishap.

Aircraft

Registration
N34LB
Reported as
Schleicher ASW-20
Category
Glider
Serial number
20342
Engine
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
William Blair
Airworthiness certificate
Special, Experimental (Special)
Departed
HMT · Hemet Ryan, CA

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
77
Injuries
Minor
Certificate
Private
Flight hours
1,025 total · 750 in this make and model · 31 in the last 90 days · 31 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
280° at 12 knots, gusting 16
Visibility
5 statute miles
Lowest ceiling
None
Temperature
88 °F, dew point 59 °F
Altimeter
29.85 inHg
Observed at
KRAL

FAA reports on this event · 1

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