Aviation Accident Summaries

Aviation Accident Summary WPR10LA276

San Diego, CA, USA

Aircraft #1

N334BB

Czech Aircraft Works Sportcruiser

Analysis

The pilot reported that the airplane was about 50 feet above ground level during the takeoff climb when the right side of the canopy opened about 4 to 6 inches. As he reached to lower it, the left side of the canopy opened. The canopy was moving up and down erratically as the pilot attempted to stabilize it, and the airplane began pitch oscillations. The pilot notified the air traffic control tower controller that the canopy was open and that he needed to return for landing immediately. As the pilot turned onto the downwind leg of the traffic pattern, the pitch oscillations became increasingly erratic. The airplane lost altitude and subsequently collided with power lines, which pitched the airplane upside down into the street below. Postaccident examination of the canopy noted that it was hinged in front of the cockpit and rotated forward when open. Examination of the latch mechanism revealed no mechanical anomalies. The pilot reported that he followed the takeoff checklist and ensured that the canopy was closed and locked by pushing up on it, although this instruction was not in the pilot operating handbook (POH). Further examination of the POH noted a lack of guidance for verifying that the canopy was locked or for operating the airplane when the canopy inadvertently opened. It is likely that during the preflight, the canopy latches could have been partially engaged such that the pilot felt enough resistance to believe that the canopy was locked. The vibration encountered during the takeoff roll and the aerodynamic flow over the canopy at liftoff may have caused the canopy to become loose and open. After the accident, the manufacturer issued guidance indicating that if the canopy opened in flight, it would raise about 2 to 3.2 inches, but the airplane should remain fully controllable.

Factual Information

On June 2, 2010, about 1035 Pacific daylight time, a Czech Aircraft Works SPOL SRO Sportcruiser, N334BB, collided with wires near Gillespie Field, El Cajon, California. Sport Flyers was operating the rental airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot sustained serious injuries. The airplane sustained substantial damage to the fuselage and empennage from impact forces. The local personal flight departed Gillespie Field about 1030, en route to Ramona, California. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot stated that he followed the takeoff checklist. He insured that the canopy was closed and locked by pushing up on it. The pilot reported that the airplane was about 50 feet above ground level during the takeoff climb when the right side of the canopy popped open about 4-6 inches. As he reached to lower it, the left side of the canopy popped open. He attempted to stabilize the climb, but the airplane became more difficult to control. The canopy was moving up and down erratically; he reached full extension of his left arm as he tried to stabilize it. He used his right hand to operate the throttle and control stick. The pilot notified the air traffic control tower (ATCT) that the canopy was open, and he needed to return for landing immediately. The controller cleared him to land on runway 27R, but did not receive a response. The controller observed the airplane lined up for runway 09L. On short final, the canopy appeared to separate. The pilot stated that he turned right crosswind and then downwind while contacting the ATCT. His headset blew off, and the "roller coaster" oscillations became increasingly erratic. The airplane lost altitude as he approached runway 09L. He saw trolley power lines in front of him, and raised the nose enough to clear them. The landing gear hooked a line, and pitched the airplane upside down into the street below. The pilot's left arm was trapped between the canopy and fuselage. He remained conscious until rescued about 40 minutes later. Examination of the canopy latches The National Transportation Safety Board investigator-in-charge and another Safety Board investigator examined the airplane. The canopy is hinged in front of the cockpit and rotates upward when open. It is locked down using two latches, one on each side of the cockpit, which engages the canopy frame. Both latches are engaged using a single lever that is positioned between the cockpit seats on the aft cockpit bulkhead. The lever operates a torque tube that is behind the cockpit seats and extends across the cabin; at each end of the toque tube are push-pull rods that operate the latch hooks. The latch lever is positioned behind the pilot's right elbow, and is not in direct view when looking forward or at the instrument panel. There was no canopy unlocked warning device. The latch mechanism exhibited no mechanical damage or misalignment. The canopy hooks aligned with the canopy frame latch slots. The canopy frame was lowered into the closed position and repeatedly latched and unlatched; no mechanical malfunction was encountered over the course of the attempts. It was noted that, on the static airplane, the canopy will stay in the lowered (closed) position even if the canopy latch is not engaged. Pilot Operating Handbook (POH) The following was noted regarding information included, and not included, in the airplane's "Pilot Operating Handbook" (POH), issued in December 2007, as revision 2.0. 1. In step #4 of the 'before takeoff' checklist, the POH stated 'Cockpit canopy - closed'. The POH did not include a step to check that the canopy was latched [or locked]. 2. The emergency procedures section of the POH did not include a procedure for the pilot to follow if the canopy became unlatched during flight. 3. There was no discussion in the POH about the airplane's flight characteristics with an unlatched canopy. Special Light Sport Airplanes are designed and constructed in accordance with ASTM International standard F2245-07. Standard F2245-07 does not specify requirements for canopy security, or the use of any type of latched/unlatched indicator in the cockpit. The ASTM standard also lists the required information that should be contained in the POH. There is no guidance in the standard indicating that the manufacturer should include information in the POH about canopy security before flight and in flight. A certified flight instructor (CFI), who has flown this make/model of airplane, reported a similar incident in March 2010. The canopy lifted several inches just after rotation. He maintained 70 knots, and the canopy stabilized in the 3-inch open position. On final, he decelerated to 60 knots, and the canopy lifted to 4 inches. As he flared, the canopy continued to increase the amount it was open. He stated that he had no pitch control problems at any of the airspeeds flown; he was able to close the canopy on the ground, but not in the air. About 1 month after the accident, the manufacturer published a change to the POH. In the other emergencies section, it discussed inadvertent opening of the canopy during takeoff. It recommended that the pilot manually check that the canopy was locked by pushing up on it prior to takeoff. It noted that if the canopy opened, it would open 2 to 3.2 inches, and could not be closed during flight. It indicated that there should be no flight control problems, no vibrations, and no change of flight characteristics. It recommended that the pilot climb to a safe altitude, maintain 65 knots (with a maximum airspeed of 75 knots), and land.

Probable Cause and Findings

The inadvertent opening of the aircraft canopy during the takeoff climb, which distracted the pilot and resulted in his failure to maintain aircraft control. Contributing to the accident was a lack of guidance in the manufacturer's pilot operating handbook addressing an open canopy during flight.

 

Source: NTSB Aviation Accident Database

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