Thursday, August 3, 2017

Sportine Aviacija LAK-17A, N128LA: Accident occurred August 02, 2017 at Garner Field Airport (KUVA), Uvalde County, Texas

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Location: Uvalde, TX
Accident Number: GAA17CA466
Date & Time: 08/02/2017, 1325 CDT
Registration: N128LA
Aircraft: AB SPORTINE AVIACIJA LAK 17
Aircraft Damage: Destroyed
Defining Event: Glider tow event
Injuries: 1 None
Flight Conducted Under: Part 91: General Aviation - Glider Tow

Analysis

The glider pilot reported that he was competing in a national soaring championship competition and that his flight was the last of several glider tows for the day. He added that the launch procedure required that every glider have a tow rope laid out next to the glider, and then a ground crewmember would hook the Schweizer tow ring first to the Schweizer tow latch on the tow airplane and then attach the Tost tow ring to his Tost-equipped glider. He further added that his glider was loaded with water ballast so that the glider could operate at maximum gross weight for competition purposes.

The glider pilot reported that the takeoff roll and liftoff were normal, but about 100 to 150 ft above ground level (agl), "the tow rope spontaneously released from the tow plane." He added that he immediately pulled his rope release handle and pitched forward to land in a grass overrun area past the departure runway, but the glider "had too much airspeed and too little area to land." Subsequently, he pulled up to avoid a "solid line of trees," entered a "gentle" right turn, and impacted a "favorable brushy area."

The glider was destroyed during the impact sequence.

The glider pilot reported that there were no preaccident mechanical malfunctions or failures with the glider that would have precluded normal operation.

The tow airplane pilot reported that this was his seventh and last tow of the day. He added that the tow rope was attached to his airplane by a ground crewmember, and then he was given instructions to "take up slack and launch as usual." He further added that the takeoff and climb out of ground effect were normal, but about 300 ft agl, the tow airplane was climbing too fast, and he radioed, "was that a rope break?" The tow airplane pilot did not receive a response, so he continued his climb. Shortly thereafter, he observed that the glider was no longer on tow and then witnessed the impact. The tow airplane pilot reported that he subsequently completed a normal landing, which included a low pass and rope release. When he moved the rope release handle to drop the rope, he felt a "lighter than normal release pressure on the tow handle."

The ground crewmember who attached the tow rope to the tow airplane and glider reported in a written statement that he "made sure the tow rope ring was placed in the proper location at the back of the mechanism." He added that he "placed the latch over the top beam in the vertical position locking the ring in place." He further added that he "made sure there was no tension on the release cable" and used his weight "in both a straight back and back and up direction assuring the tow ring was securely locked in place."

The glider contest manager reported that the tow airplane involved in the accident was the only airplane with a Schweizer tow hitch. The other tow airplanes being used were equipped with Tost tow hitches. The manager reported that for future contests, only tow airplanes equipped with Tost tow hitches will be used.

A Federal Aviation Administration (FAA) aviation safety inspector reported that the glider tow rope and tow rope rings were found intact just beyond the end of the departure runway, and no anomalies were observed. He added that he performed a functional check of the tow hitches on the tow airplane and glider, and no anomalies were observed.

FAA Advisory Circular, "Acceptable Methods, Techniques, and Practices – Aircraft Alterations," AC No. 43.13-2B, stated, in part: "The Schweizer is a simple over center L-hook type with a rubber tension block to preload the release lever."

The FAA Glider Flying Handbook stated, in part:

Schweizer Tow Hook

Prior to use, the tow hook and release arm should be inspected for damage, cracks, deformation, and freedom of movement on the pivot bolt. Visually check the tow hook and ensure that the hook properly engages the release arm. Inspect the rubber spacer for general condition and check the condition of the release cable. Inside the cockpit, check to see that the manual release lever is not rubbing against the aircraft seat or any other obstructions, and check the security of the release handle assembly and the cable attachment.

It is likely that the ground crewmember did not fully engage the tow hook release arm during preflight, and that, during the initial climb, the tow ring prematurely released from the tow airplane. 

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The ground crewmember's failure to fully engage the tow hook release arm during preflight, which resulted in the premature release of the glider at insufficient altitude to complete a safe landing.

Findings

Aircraft
Aerial tow equipment section - Incorrect use/operation (Cause)

Personnel issues
Use of equip/system - Ground crew (Cause)

Factual Information

History of Flight

Initial climb
Glider tow event (Defining event)
Collision with terr/obj (non-CFIT) 

Pilot Information

Certificate: Flight Instructor; Commercial
Age: 67, Male
Airplane Rating(s): None
Seat Occupied: Single
Other Aircraft Rating(s): Glider
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): Glider
Toxicology Performed: No
Medical Certification: None None
Last FAA Medical Exam:
Occupational Pilot: No
Last Flight Review or Equivalent: 07/16/2017
Flight Time: (Estimated) 1241 hours (Total, all aircraft), 159 hours (Total, this make and model), 1224 hours (Pilot In Command, all aircraft), 48 hours (Last 90 days, all aircraft), 23 hours (Last 30 days, all aircraft) 

Aircraft and Owner/Operator Information

Aircraft Manufacturer: AB SPORTINE AVIACIJA
Registration: N128LA
Model/Series: LAK 17 A
Aircraft Category: Glider
Year of Manufacture: 2004
Amateur Built: No
Airworthiness Certificate: Experimental; Restricted
Serial Number: 151
Landing Gear Type: Skid
Seats: 1
Date/Type of Last Inspection: 03/17/2017, Annual
Certified Max Gross Wt.: 1100 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 429.76 Hours at time of accident
Engine Manufacturer: Solo
ELT: Not installed
Engine Model/Series: 2350
Registered Owner: On file
Rated Power: 26 hp
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KUVA, 940 ft msl
Observation Time: 1835 UTC
Distance from Accident Site: 2 Nautical Miles
Direction from Accident Site: 176°
Lowest Cloud Condition: Clear
Temperature/Dew Point: 34°C / 18°C
Lowest Ceiling: None
Visibility:  10 Miles
Wind Speed/Gusts, Direction: Calm
Visibility (RVR):
Altimeter Setting: 30 inches Hg
Visibility (RVV):
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: UVALDE, TX (UVA)
Type of Flight Plan Filed: None
Destination: UVALDE, TX (UVA)
Type of Clearance: None
Departure Time: 1325 CDT
Type of Airspace: Class G

Airport Information

Airport: GARNER FIELD (UVA)
Runway Surface Type: N/A
Airport Elevation: 941 ft
Runway Surface Condition: Vegetation
Runway Used: N/A
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing:  Forced Landing

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Destroyed
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 29.211389, -99.743611 (est)

Federal Aviation Administration / Flight Standards District Office; San Antonio, Texas

Investigation Docket - National Transportation Safety Board:  https://dms.ntsb.gov/pubdms


Aviation Accident Factual Report - National Transportation Safety Board: https://app.ntsb.gov/pdf 

Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf

http://registry.faa.gov/N128LA

Location: Uvalde, TX
Accident Number: GAA17CA466
Date & Time: 08/02/2017, 1325 CDT
Registration: N128LA
Aircraft: AB SPORTINE AVIACIJA LAK 17
Aircraft Damage: Destroyed
Defining Event: Glider tow event
Injuries: 1 None
Flight Conducted Under:  Part 91: General Aviation - Glider Tow

The glider pilot reported that he was competing in a national soaring championship competition and his flight was the last of several glider tows for the day. He added that, the launch procedure required that every glider have a tow rope laid out next to the glider, and then a ground crewmember would hook the Schweizer tow ring first to the Schweizer tow latch on the tow airplane, and then attach the Tost tow ring to his Tost equipped glider. He further added that, his glider was loaded with water ballast so that the glider could operate at maximum gross weight for competition purposes.

The glider pilot reported that the takeoff roll and liftoff were normal, but about 100 to 150 ft above ground, "the tow rope spontaneously released from the tow plane." He added that he immediately pulled his rope release handle and pitched forward to land in a grass overrun area past the departure runway, but the glider "had too much airspeed and too little area to land." Subsequently, he pulled up to avoid a "solid line of trees," entered a "gentle" right turn, and impacted a "favorable brushy area."

The glider was destroyed during the impact sequence.

The glider pilot reported that there were no preaccident mechanical malfunctions or failures with the glider that would have precluded normal operation.

A Federal Aviation Administration (FAA) aviation safety inspector reported that the glider tow rope and tow rope rings were found intact just beyond the end of the departure runway and no anomalies were observed. He added that he performed a functional check of the tow hitches on the tow airplane and glider and no anomalies were observed.

The tow airplane pilot reported that this was his seventh tow, and last tow of the day. He added that the tow rope was attached to his airplane by a ground crewmember, and then he was given instructions to "take up slack and launch as usual." He further added that the takeoff and climb out of ground effect were normal, but about 300 ft above ground, the tow airplane was climbing too fast and he radioed, "was that a rope break?" The tow airplane pilot did not receive a response, so he continued his climb; shortly thereafter, he observed the glider was no longer on tow and witnessed the impact. Subsequently, the tow airplane pilot reported that he completed a normal landing, which included a low pass and rope release. When he moved the rope release handle to drop the rope, he felt a "lighter than normal release pressure on the tow handle."

The ground crewmember, who attached the tow rope to the tow airplane and glider, reported in a written statement that he, "made sure the tow rope ring was placed in the proper location at the back of the mechanism." He added that he, "placed the latch over the top beam in the vertical position locking the ring in place." He further added that he "made sure there was no tension on the release cable" and used his weight "in both a straight back and back and up direction assuring the tow ring was securely locked in place."

The glider contest manager reported that the tow airplane involved in the accident was the only airplane with a Schweizer tow hitch. The other tow airplanes being used were equipped with Tost tow hitches. The manager reported that for future contests, only tow airplanes equipped with Tost tow hitches will be used.

The FAA Advisory Circular, Acceptable Methods, Techniques, and Practices – Aircraft Alterations, AC No. 43.13-2B, stated in part: "The Schweizer is a simple over center L-hook type with a rubber tension block to preload the release lever."

The FAA Glider Flying Handbook stated in part:

Schweizer Tow Hook

Prior to use, the tow hook and release arm should be inspected for damage, cracks, deformation, and freedom of movement on the pivot bolt. Visually check the tow hook and ensure that the hook properly engages the release arm. Inspect the rubber spacer for general condition and check the condition of the release cable. Inside the cockpit, check to see that the manual release lever is not rubbing against the aircraft seat or any other obstructions, and check the security of the release handle assembly and the cable attachment.

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