SEA02LA140

NTSB accident investigation · Blanik L-13 · Belgrade, MT · July 31, 2002

Accident · Minor injuriesLimited investigationFinal report
Date
July 31, 2002, 14:45 local (20:45 UTC)
Place
Belgrade, MT
Injuries
2 minor
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N70741Blanik L-13
Weather
Visual (VMC) · Day
Status
Completed · report April 8, 2003
Report
Approved by Office Director
Parties
FAA FSDO
FAA report
20020731018669A
Case key
55350

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 glider pilot's improper in-flight planning decision and his failure to attain the proper touchdown point. Contributing to the accident were the inadvertent activation of the speed brakes, the pilot's failure to maintain altitude, the high vegetation and the ditch.

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.

On ground/water encounter with terrain/waterLanding - roll
In-flight planning/decision - improperPilot in commandCause
Proper touchdown point - not obtainedPilot in commandCause
Speed brakes - inadvertent activationPilot in commandFactor
Altitude - not maintainedPilot in commandFactor
Terrain condition - high vegetationFactor
Terrain condition - ditchFactor
On ground/water encounter with terrain/waterLanding - roll
Terrain condition - high vegetationFactor
Terrain condition - ditchFactor

Analysis

Just about the time the glider pilot was ready to initiate his base turn for the parallel sod runway, the tower controller asked him if he saw the traffic on a one mile final to the paved runway. According to the pilot, he then let go of the spoiler handle (the spoilers were partially deployed), in order to reach the microphone that was stored in a pocket on the right side of the glider. He advised the tower that he did not have the traffic in sight, put the microphone back in the pocket, and then reached back for the spoiler handle. At that time he discovered that the spoilers had deployed to the full open position. The pilot then immediately retracted the spoilers and made a turn to final. After turning final, the pilot realized that he probably would not be able to make it to the threshold of the sod runway, but because of the aircraft on final for the paved runway, he made the decision not to request a change to that runway (the threshold of which was approximately 2,500 feet closer to his position at the time). As the pilot continued on toward the threshold of the sod runway, he attempted to maneuver toward its right side in order to avoid some stakes that were between him and the runway threshold, and in order to land well clear of the paved runway. Ultimately the aircraft touched down approximately 200 feet short of the sod runway threshold and 50 feet to the right of its right edge. Although the initial touchdown in the tall weeds was uneventful, almost immediately after starting the landing roll, the aircraft impacted a ditch that the pilot had not been aware of.

Factual narrative

On July 31, 2002, approximately 1445 mountain daylight time, a Blanik L-13, N70741, impacted a ditch after landing short of the runway at Gallatin Field Airport, Belgrade, Montana. The aircraft was owned by Big Sky Soaring Inc., and operated by Sunbird Aviation. The private pilot and his passenger received minor injuries, and the glider sustained substantial damage. The 14 CFR Part 91 personal pleasure flight departed Gallatin Field Airport, Belgrade, Montana, approximately one hour prior to the accident, and was being operated in visual meteorological conditions. No flight plan had been filed.

According to the pilot, he released from the tow plane just south of Saddle Peak, and soared Bridger Ridge until about 1430. At that time he called Bozeman Tower to report leaving the ridge and to request landing on the grass/sod runway located just to the right of the paved runway (see attached satellite image). The tower reported the current winds as 300 degrees at 20 knots, and instructed the pilot to report 30 seconds prior to entering the downwind for sod runway 30. When he was 30 seconds from a downwind entry, the pilot advised the tower of this position, and after being cleared to land on the sod runway, entered a left downwind. Just about the time the pilot was ready to initiate his base turn, the tower controller asked him if he saw the traffic on a one mile final to the paved runway. According to the pilot, he then let go of the spoiler handle (the spoilers were partially deployed), in order to reach the microphone that was stored in a pocket on the right side of the glider. He advised the tower that he did not have the traffic in sight, put the microphone back in the pocket, and then reached back for the spoiler handle. At that time he discovered that the spoilers had deployed to the full open position. The pilot then immediately retracted the spoilers and made a turn to final. After turning final, the pilot realized that he probably would not be able to make it to the threshold of the sod runway, but because of the aircraft on final for the paved runway, he made the decision not to request a change to that runway (the threshold of which was approximately 2,500 feet closer to his position at the time). As the pilot continued on toward the threshold of the sod runway, he attempted to maneuver toward its right side in order to avoid some stakes that were between him and the runway threshold, and in order to land well clear of the paved runway. Ultimately the aircraft touched down approximately 200 feet short of the sod runway threshold and 50 feet to the right of its right edge. Although the initial touchdown in the tall weeds was uneventful, almost immediately after starting the landing roll, the aircraft encountered a ditch that the pilot had not been aware of. Upon impacting the far wall of the ditch, the aircraft sustained substantial damage generated by the force of the collision.

Aircraft

Registration
N70741
Reported as
Blanik L-13
Category
Glider
Serial number
027341
Airframe hours
2,100
Engine
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
Big Sky Soaring, Inc.
Airworthiness certificate
Standard, Normal
Last inspection
Annual · June 7, 2002 · 20 hours before
Departed
BZN · Belgrade, MT
Destination
BZN · MT
Airport
BZN · Gallatin Field, runway 30R, 2,000 × 150 ft, grass/turf

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
72
Injuries
Minor
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, Valid Medical--w/ waivers/lim
Last flight review
June 1, 2001
Seat
Front
Flight hours
789 total · 80 in this make and model · 754 as pilot in command · 37 in the last 90 days · 15 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
290° at 20 knots, gusting 31
Visibility
10 statute miles
Lowest ceiling
None
Temperature
84 °F, dew point 23 °F
Altimeter
29.95 inHg
Observed at
KBZN

Docket · 2

The files NTSB released with the investigation on December 31, 2002, on NTSB’s docket system: statements, records, photos and specialists’ reports. 456 KB 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.

Other investigations on N70741 · 1

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