CEN12LA605

NTSB accident investigation · Burkhart Grob G 103 Twin II · El Paso, TX · September 1, 2012

Accident · FatalLimited investigationFinal report
Date
September 1, 2012, 11:00 local (17:00 UTC)
Place
El Paso, TX
Injuries
1 fatal
Damage
Substantial damage
Phase of flight
Takeoff
Aircraft
N5489XBurkhart Grob G 103 Twin II
Defining event
Takeoff: Loss of control in flight
Weather
Visual (VMC) · Day
Status
Completed · report June 19, 2013
Report
Approved by Office Director
NTSB office
Central Region
Parties
FAA/FSDO
FAA report
20120901020049A
Case key
84928

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 maintain glider control while attempting to take off using a ground winch, which resulted in an inadvertent stall low to the ground. Contributing to the accident was the ground winch, which was unable to produce enough speed for a successful glider launch.

Findings · 4

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.

Use of equip/info: aircraft controlPersonnel issues › Task performance · PilotAll aircraft: 9,295 casesProbable cause
Towing and taxiing: towingAircraft › Aircraft handling/service · Related operating infoAll aircraft: 10 casesProbable cause
Performance/control parameters: airspeedAircraft › Aircraft oper/perf/capability · Not attained/maintainedAll aircraft: 1,681 casesProbable cause
Misc hardwareAircraft › Fluids/misc hardware · Not specifiedAll aircraft: 41 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 club was launching gliders via a mechanical ground winch. On the first launch attempt, the glider overflew the tow cable and it automatically disconnected when the glider was low to the ground. The glider was able to make a safe landing on the runway. The pilot was overheard saying that the first launch failed because he should have initiated the climb sooner. On the second attempt, the glider once again overran the tow cable. Before the tow cable released, the pilot lowered the nose to pick up the slack in the cable and he instructed the winch operator to go faster. These two steps appeared to have corrected the problem, and the pilot initiated a climb. Shortly after, the glider began to overfly the cable again and it disconnected. The glider entered free flight just above stall speed about 75 feet above the runway. A witness saw the glider nose over and thought the pilot was going to land. Instead, the glider descended rapidly and drifted to the left toward a taxiway. The witness saw the wings of the glider rock back and forth before it impacted the ground hard. Examination of the glider and release hook revealed no mechanical anomalies. The ground winch's engine was reportedly running rough and most likely was unable to produce enough speed to launch the glider.

Factual narrative

On September 1, 2012, about 1100 mountain daylight time, N5489X, a Burkhart Grob G103 Twin II glider, sustained substantial damage when it landed hard during an attempted takeoff using a ground winch at the Horizon Airport (T27) near El Paso, Texas. The commercial pilot was fatally injured. The glider was registered to and operated by the El Paso Soaring Society Incorporated, El Paso, Texas. Visual meteorological conditions prevailed and no flight plan was filed for the local flight conducted under 14 Code of Federal Regulations Part 91. The El Paso Soaring Society was using the ground winch to launch gliders because their tow airplane was down for maintenance. The winch was set up on the overrun area on the east side of Runway 08. According to a witness, a week before the accident, he attended a class on how to launch a glider using the ground winch. The class was given by the pilot and the person who operated the winch on the day of the accident. The witness said the class was taught from both a pilot and winch-operating perspective. The following weekend, the witness returned to the airport to assist with the glider launches. He said that on the first launch attempt, he ran alongside the glider's wing until it got airborne. When the glider was approximately 15 feet above the ground, it overran the winch cable and the center of gravity (CG) hook automatically disconnected. The glider landed straight ahead without incident. While ground-towing the glider back to the takeoff area, the witness heard the pilot telling the winch operator to do the same exact thing with the winch as he did on the first attempt. The pilot felt the first launch had failed because he didn't initiate a climb soon enough. During the second attempt, the witness said the glider once again overflew the winch cable. He said, "According to the class [the pilot] gave the previous week, he performed the correct procedure - he lowered the nose to let the slack out of the cable. As this happened, he also came on the radio and directed the winch to go "faster". Then, once it started pulling him again, he raised the nose up as he was supposed to do in order to initiate a climb. After he did this, the cable once again seemed to develop some slack and the glider out ran it." The witness said the cable disconnected and the glider was in free-flight approximately 75 feet above the ground and appeared to be traveling just above stall speed. He then saw the glider nose over as if the pilot was preparing to land. But the glider began to sink rapidly as it drifted to the left toward the taxiway. The witness then saw the wings of the glider rock back and forth before it hit the ground "very hard." According to an inspector with the Federal Aviation Administration (FAA), the glider came to rest just north of the taxiway. The area was damaged and the tail had separated from the airframe. Examination of the CG hook revealed no mechanical deficiencies and functioned normally when tested. Theinspector also said the ground winch utilized a 350-cubic-inch Chevrolet engine with a two-speed automatic transmission. Club members reported the winch had only been used about 9 times in the last 4 years. The pilot's son, who was standing behind the winch on both launch attempts, said the winch engine sounded as if it was producing a high RPM, but was running rough. The pilot held a commercial pilot certificate for airplane single-engine land and glider. He also had a certified flight instructor certificate for gliders. The pilot's last FAA Third Class medical was issued on December 28, 2011. At that time, he reported a total of 1,500 flight hours. Weather at El Paso International Airport (ELP), El Paso, Texas, approximately 9 miles northwest of T27, at 1051, was reported as wind from 150 degrees at 4 knots, visibility 10 miles, clear skies, temperature 30 degrees Celsius, dewpoint 6 degrees Celsius, and a barometric pressure setting of 30.16 inches Hg.

Aircraft

Registration
N5489X
Reported as
Burkhart Grob G 103 Twin II
Category
Glider
Serial number
3877-K-115
Damage
Substantial damage
Flight
Glider tow · Part 91
Operator
El Paso Soaring Society Inc
Registered owner
El Paso Soaring Society Inc
Airworthiness certificate
Standard, Normal
Departed
T27 · El Paso, TX
Destination
T27 · El Paso, TX
Airport
T27 · Horizon Airport, runway 08, 6,885 × 50 ft, asphalt

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
76
Injuries
Fatal
Certificates
Flight instructor, Commercial
Airplane ratings
Single-engine land
Medical
Class 3, With waivers/limitations
Seat
Rear
Flight hours
1,500 total

Weather

Conditions
Visual (VMC) · Day
Wind
150° at 4 knots
Visibility
10 statute miles
Temperature
86 °F, dew point 43 °F
Altimeter
30.15 inHg
Observed at
ELP, 9 nm away

Docket · 2

The files NTSB released with the investigation on April 24, 2013, on NTSB’s docket system: statements, records, photos and specialists’ reports. 654 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.