GAA17CA466

NTSB accident investigation · AB Sportine Aviacija LAK 17 · Uvalde, TX · August 2, 2017

Accident · No injuriesData collectionFinal report
Date
August 2, 2017, 13:25 local (18:25 UTC)
Place
Uvalde, TX
Injuries
1 uninjured
Damage
Destroyed
Phase of flight
Initial climb
Aircraft
N128LAAB Sportine Aviacija LAK 17
Defining event
Initial climb: Glider tow event
Weather
Visual (VMC) · Day
Status
Completed · report December 15, 2017
Report
Approved by Office Director
NTSB office
General Aviation Accidents
Parties
FAA/ FSDO
FAA report
20170802010279A
Case key
95742

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

On this page

Probable cause

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 · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Fuselage: aerial tow equipment sectionAircraft › Aircraft structures · Incorrect use/operationAB Sportine Aviacija LAK-17A: 1 caseAll aircraft: 7 casesProbable cause
Use of equip/info: use of equip/systemPersonnel issues › Task performance · Ground crewAB Sportine Aviacija LAK-17A: 1 caseAll aircraft: 1,391 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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 beused. 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.

Factual narrative

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 wassecurely 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.

Aircraft

Registration
N128LA
Reported as
AB Sportine Aviacija LAK 17 (A)
Category
Glider
Serial number
151
Built
2004
Airframe hours
429.76
Engine
Solo 2350, 26 horsepower, reciprocating
Damage
Destroyed
Flight
Glider tow · Part 91
Airworthiness certificate
Special, Experimental (Special); Special, Restricted (Special)
Last inspection
Annual · March 17, 2017
Departed
UVA · Uvalde, TX
Destination
UVA · Uvalde, TX
Airport
UVA · Garner Field
Equipment
Satellite tracking device

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
67
Injuries
None
Certificates
Commercial, Flight instructor
Last flight review
July 16, 2017
Seat
Single
Restraint
4-point
Flight hours
1,241 total · 159 in this make and model · 1,224 as pilot in command · 48 in the last 90 days · 23 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
None
Temperature
93 °F, dew point 64 °F
Altimeter
30.00 inHg
Observed at
KUVA, 2 nm away

Docket · 8

The files NTSB released with the investigation on November 22, 2017, on NTSB’s docket system: statements, records, photos and specialists’ reports. 7.9 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.