Narrative:

On initial climb after takeoff in an experimental self-launching motor glider; the canopy came open and part of it broke off; hitting the tip of the (aft pusher) propeller and part of the fuselage. Control was maintained and an immediate landing was made without incident or further damage to the aircraft. There were no injuries and no property damage other than the aircraft. All of the canopy pieces that departed the aircraft were recovered. Three possible causes exist: (1) failure of the canopy latch mechanism to function properly; (2) inadvertent release of the latch by the pilot; (3) failure by the pilot to properly secure the latch. I will address considerations for each possibility in turn. 1) failure of the latch mechanism: inspection of the aircraft and recovered parts of the canopy did not show any breakage of the canopy hardware. However; the aircraft is experimental and the latch release only requires minimal force to move a protruding lever from forward to aft to release the canopy. There have been anecdotal reports of failures (in same make/model) of the mechanism to function properly leading to opening of the canopy in flight. One such incident (reported in an email to purchasers of the aircraft by the importer) occurred shortly after takeoff and was associated with a nose up; then nose down; attitude leading to a crash; substantial aircraft damage and serious injury to the pilot. I do not know for sure if the manufacturer or importer implemented a corrective action but supposedly the latching mechanism was redesigned/changed prior to the manufacture/importation of the specific glider involved in my event. Also; following that accident; there was a question of wake turbulence as a contributing factor. At the time of my event there was a 10-12 KT wind essentially aligned with the runway and variable 0-5 KT additional gust component -- so there was some potential for wind shear/turbulence. Wake turbulence was not a possibility as there were no other aircraft in the vicinity for about 10 minutes prior to the event.2) inadvertent release of the latch due to minimal force required to move the protruding lever by the pilot is a distinct possibility and this action seemed to be the cause of at least one other in-flight canopy opening event described in an on-line user group discussion regarding this aircraft type. A potential corrective action to prevent this from happening in the future would be the addition of a velcro strap around the release lever. This strap would be designed to avoid movement of the canopy release lever with minimal force but still allow it to be moved with substantial force during emergency egress or with minimal force if using a two-step process of unhooking the velcro strap and then moving the release lever aft. 3) there is also the possibility that the latch was not securely closed prior to takeoff. A potential contributing factor if this did occur is a cord that attaches to the canopy and to the bulkhead behind the pilot. This cord is meant to support the weight of the canopy in the open position - preventing it from contacting the side of the fuselage. On occasion; this cord has lodged between the canopy and the fuselage -- interfering with full closure of the canopy. When this has occurred in the past; it was quite apparent that the canopy had not closed completely. I have no indication that this was the issue during my event as the canopy appeared fully closed prior to takeoff. Corrective action for this possibility includes use of a shorter; elastic; and/or weighted cord to reduce the chance of it being lodged between the canopy and the fuselage and interfering with full closure. Another possible contributing factor (if this did occur but was missed) is that my pre-flight check was potentially rushed. While I was in position on the runway preparing for departure; another aircraft reported a 2.5 mile final approach to the same runway (without any other radio calls indicating normalpattern entry at this uncontrolled airport). While the approaching aircraft may have led me to expedite my departure to clear the runway; I do not recall any indication that the canopy was not securely closed. Corrective action would include proper use of pre-flight check-list ('canopy secure' is on my list) and extra care if feeling 'rushed' for any reason.

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Original NASA ASRS Text

Title: The pilot of an AC-5M motor glider reported his canopy came open on initial climb; part of which broke off and struck the prop and fuselage.

Narrative: On initial climb after takeoff in an experimental self-launching motor glider; the canopy came open and part of it broke off; hitting the tip of the (aft pusher) propeller and part of the fuselage. Control was maintained and an immediate landing was made without incident or further damage to the aircraft. There were no injuries and no property damage other than the aircraft. All of the canopy pieces that departed the aircraft were recovered. Three possible causes exist: (1) failure of the canopy latch mechanism to function properly; (2) inadvertent release of the latch by the pilot; (3) failure by the pilot to properly secure the latch. I will address considerations for each possibility in turn. 1) Failure of the latch mechanism: inspection of the aircraft and recovered parts of the canopy did not show any breakage of the canopy hardware. However; the aircraft is experimental and the latch release only requires minimal force to move a protruding lever from forward to aft to release the canopy. There have been anecdotal reports of failures (in same make/model) of the mechanism to function properly leading to opening of the canopy in flight. One such incident (reported in an email to purchasers of the aircraft by the importer) occurred shortly after takeoff and was associated with a nose up; then nose down; attitude leading to a crash; substantial aircraft damage and serious injury to the pilot. I do not know for sure if the manufacturer or importer implemented a corrective action but supposedly the latching mechanism was redesigned/changed prior to the manufacture/importation of the specific glider involved in my event. Also; following that accident; there was a question of wake turbulence as a contributing factor. At the time of my event there was a 10-12 KT wind essentially aligned with the runway and variable 0-5 KT additional gust component -- so there was some potential for wind shear/turbulence. Wake turbulence was not a possibility as there were no other aircraft in the vicinity for about 10 minutes prior to the event.2) Inadvertent release of the latch due to minimal force required to move the protruding lever by the pilot is a distinct possibility and this action seemed to be the cause of at least one other in-flight canopy opening event described in an on-line user group discussion regarding this aircraft type. A potential corrective action to prevent this from happening in the future would be the addition of a Velcro strap around the release lever. This strap would be designed to avoid movement of the canopy release lever with minimal force but still allow it to be moved with substantial force during emergency egress or with minimal force if using a two-step process of unhooking the Velcro strap and then moving the release lever aft. 3) There is also the possibility that the latch was not securely closed prior to takeoff. A potential contributing factor if this did occur is a cord that attaches to the canopy and to the bulkhead behind the pilot. This cord is meant to support the weight of the canopy in the open position - preventing it from contacting the side of the fuselage. On occasion; this cord has lodged between the canopy and the fuselage -- interfering with full closure of the canopy. When this has occurred in the past; it was quite apparent that the canopy had not closed completely. I have no indication that this was the issue during my event as the canopy appeared fully closed prior to takeoff. Corrective action for this possibility includes use of a shorter; elastic; and/or weighted cord to reduce the chance of it being lodged between the canopy and the fuselage and interfering with full closure. Another possible contributing factor (if this did occur but was missed) is that my pre-flight check was potentially rushed. While I was in position on the runway preparing for departure; another aircraft reported a 2.5 mile final approach to the same runway (without any other radio calls indicating normalpattern entry at this uncontrolled airport). While the approaching aircraft may have led me to expedite my departure to clear the runway; I do not recall any indication that the canopy was not securely closed. Corrective action would include proper use of pre-flight check-list ('canopy secure' is on my list) and extra care if feeling 'rushed' for any reason.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.