Aviation Accident Summaries

Aviation Accident Summary DEN99LA028

CANON CITY, CO, USA

Aircraft #1

N173SS

Burkhart Grob G103 TWIN ASTIR

Analysis

During initial climb from takeoff, the rear canopy of the glider opened. When the pilot reached to close the canopy, the glider ballooned above the tow plane. The pilot turned the glider to the left and lowered the nose to maintain airspeed. The glider then impacted the ground before he leveled out. According to the passenger and several witnesses, prior to takeoff, the glider pilot signaled the tow pilot that he was ready for takeoff. However, the departure was halted so that the glider pilot could be given a handheld radio in order for communications to be established between the glider and the tow plane. The glider pilot opened the canopy in order to receive the radio, then re-closed it. The first ground scars were observed approximately 1,100 feet prior to the end of the paved section of runway 29, and an additional 800 feet of dirt extends beyond the runway prior to the existence of any obstructions. At the request of an FAA inspector, a postaccident examination of the rear canopy latch was performed. According to the mechanic who performed the inspection, 'the rear canopy latch was found to be operational.'

Factual Information

On December 27, 1998, at 1115 mountain standard time, a Burkhart Grob Flugzeugbau G103 Twin Astir glider, N173SS, was substantially damaged when it impacted the ground following a forced landing after the canopy opened during initial climb from takeoff at Freemont County Airport, Canon City, Colorado. The commercial pilot received minor injuries and one passenger received serious injuries. Visual meteorological conditions prevailed for the local area personal flight being conducted under Title 14 CFR Part 91, and no flight plan was filed. The flight originated approximately five minutes before the accident. According to the glider pilot, the passenger "was strapped in and [the] canopy [was] latched in the front seat." He then "latched the canopy in the rear seat and performed a normal pre-takeoff checklist." The tow plane was attached and takeoff was normal. After a positive rate of climb was established, the rear canopy "popped open." When the pilot attempted to close the canopy, the glider ballooned above the tow plane. He then instructed the passenger to pull the tow rope release. He turned to the left in an attempt to land on flatter terrain, and lowered the nose to maintain airspeed. According to the pilot, the glider impacted the ground before he could level out. According to the passenger and several witnesses, the glider pilot signaled the tow pilot that he was ready for takeoff. However, the departure was halted so that the glider pilot could be given a handheld radio in order for communications to be established between the glider and the tow plane. The glider pilot opened the canopy in order to receive the radio, then re-closed it. The glider pilot then signaled a second time that he was ready for takeoff. After departure, the passenger stated that the aircraft was 5 to 10 feet above the runway when the canopy latch opened. According to a witness, at approximately 100 feet above the ground (agl), "the glider pitched up steeply, lifting the tail of the tow plane. The glider and tow plane both released the rope which landed near taxiway A3 [located mid-runway]... The glider then traveled approximately 1,500 to 2,000 feet down the runway before turning left and impacting the ground left wing first." According to a witness, the first ground scars where the glider impacted the ground were observed approximately 1,100 feet prior to the end of the paved section of runway 29. In addition, there is another 800 feet of dirt beyond the paved runway prior to the existence of any obstructions. At the request of the Investigator-In-Charge, an FAA inspector supervised an examination of the rear canopy latch. According to the mechanic who performed the inspection, "the rear canopy latch was found to be operational."

Probable Cause and Findings

The glider pilot's failure to follow proper preflight procedures, and his failure to control the aircraft when the latch opened during flight. A factor was his failure to properly latch the canopy, and to utilize all available runway during the forced landing.

 

Source: NTSB Aviation Accident Database

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