Narrative:

This flight was instructional. We were flying a rans S-6S. The pilot; a multi engine commercial pilot who's family also owns and built the aircraft; was working with me on his single commercial add-on. This airplane was owned by his uncle and built by his grandfather. Initially we were unsure whether we could use the airplane for a single engine commercial add on; however after talking to the FSDO we were told that as long as the designated pilot examiner (dpe) found the aircraft acceptable we could use it. My student called the dpe said he would be willing to use the rans S-6S for a single engine commercial add-on. After about 30 minutes of air work (eights-on-pylons primarily) we returned to the airport to practice take-takeoffs and landings; short and soft fields; but primarily the 'power off-180.' we were in a right traffic pattern for the runway with a cessna 152 and a challenger 300. We did three landings and decided after the third that it was too difficult to work in with the challenger and a cessna 152; so we decided to make the fourth our final landing. We were on the right downwind for the runway at pattern altitude when I noticed it felt like a vent had come open; it got windy and cold. I began to look around to see where it was coming from while my student; the pilot; informed the tower we were 'right midfield downwind;' as we were instructed to do. The tower cleared us for 'the option [for the] runway.' just after the midfield the pilot/my student noticed that the forward pin at the top of the pilot side door was missing. The door is held on by two pins at the top of the door; one aft; one forward; and two latches at the bottom. Because the top forward pin had come out the door was able to drop slightly; this caused a slight opening which caused the wind inside the cabin. This had to have happened after our last landing; which was smooth. There was no wind during the flight and the pin was most certainly there before takeoff. While doing the pre-flight both doors were fully open and being held straight and in place by both pins on both sides. After the pin came out sometime after the third landing; the only thing holding it on was the top aft pin; and the two latches at the bottom. By now we were turning base and the door was holding with no apparent problem. The pilot; my student; was flying and continued the visual approach. We turned final and leveled the wings. At about a one mile final; just outside the airport perimeter fence; the door was suddenly ripped from the airplane. The pilot; my student; pulled the power to idle and let the nose drop. I felt that with the increased drag due to the lack of a door we may not have sufficient altitude to make the runway without power and a loss in airspeed or altitude at this point would not be advantageous; therefore I immediately told him to add power and continue flying. The aircraft seemed to continue flying without any obvious problems. I asked for control and the pilot gave me the controls. I then asked if he could safely see if there was any damage to the tail. He stated that he did not have a good view of any part of the tail. It seemed as though the airplane was flying without any problems. I did not have a push to talk switch on my side so I advised the pilot to quickly request a full stop landing; tower then cleared us to land on the runway. I returned control of the aircraft to the pilot and he made a safe landing on the runway. We came to a stop and were given a clearance by tower to remain on the tower frequency and to taxi back to the ramp. We knew that the door was in a field outside the airport perimeter but did not know the aircraft sustained any other damage at this point. We taxied in via the instruction given by tower. Once reaching the hangar and exiting the aircraft we realized the damage it had done. The underside of the wing had roughly a two foot cut in the fabric. The fuselage just aft of the wing had two large tears/holes; one roughly one foot high by two feet long; and the other roughly one square foot. The left horizontal stabilizer was able to be moved up and down roughly a half inch in both directions. The rudder had a round hole a few inches in diameter on the left side which exited through to the right. The elevator also had a hole/tear which entered through the bottom and exited through the top. After realizing the damage to the airplane other than the door we decided we most likely needed to file a report. The pin that came off does not have a cotter pin through it; instead it uses a lock nut. The pilot said it was built according to specifications provided by manufacturer. A lock nut is not sufficient means to hold the pin in place. Luckily the door did not do more damage than it did. We would not have had time to recover at the altitude and airspeed where the incident had occurred if our control surfaces had been adversely affected.

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Original NASA ASRS Text

Title: The left door of a Ran S-6S came off on short final after the lock nut holding the door's top hinge pin fell out. The pilot and instructor landed safely. Inspection revealed extensive wing; horizontal stabilizer; elevator and rudder damage.

Narrative: This flight was instructional. We were flying a Rans S-6S. The pilot; a multi engine commercial pilot who's family also owns and built the aircraft; was working with me on his single commercial add-on. This airplane was owned by his uncle and built by his grandfather. Initially we were unsure whether we could use the airplane for a Single Engine Commercial add on; however after talking to the FSDO we were told that as long as the Designated Pilot Examiner (DPE) found the aircraft acceptable we could use it. My student called the DPE said he would be willing to use the Rans S-6S for a single engine commercial add-on. After about 30 minutes of air work (eights-on-pylons primarily) we returned to the airport to practice take-takeoffs and Landings; Short and soft fields; but primarily the 'power off-180.' We were in a right traffic pattern for the runway with a Cessna 152 and a Challenger 300. We did three landings and decided after the third that it was too difficult to work in with the Challenger and a Cessna 152; so we decided to make the fourth our final landing. We were on the right downwind for the runway at pattern altitude when I noticed it felt like a vent had come open; it got windy and cold. I began to look around to see where it was coming from while my student; the pilot; informed the Tower we were 'right midfield downwind;' as we were instructed to do. The Tower cleared us for 'the option [for the] runway.' Just after the midfield the pilot/my student noticed that the forward pin at the top of the pilot side door was missing. The door is held on by two pins at the top of the door; one aft; one forward; and two latches at the bottom. Because the top forward pin had come out the door was able to drop slightly; this caused a slight opening which caused the wind inside the cabin. This had to have happened after our last landing; which was smooth. There was no wind during the flight and the pin was most certainly there before takeoff. While doing the pre-flight both doors were fully open and being held straight and in place by both pins on both sides. After the pin came out sometime after the third landing; the only thing holding it on was the top aft pin; and the two latches at the bottom. By now we were turning base and the door was holding with no apparent problem. The pilot; my student; was flying and continued the visual approach. We turned final and leveled the wings. At about a one mile final; just outside the airport perimeter fence; the door was suddenly ripped from the airplane. The pilot; my student; pulled the power to idle and let the nose drop. I felt that with the increased drag due to the lack of a door we may not have sufficient altitude to make the runway without power and a loss in airspeed or altitude at this point would not be advantageous; therefore I immediately told him to add power and continue flying. The aircraft seemed to continue flying without any obvious problems. I asked for control and the pilot gave me the controls. I then asked if he could safely see if there was any damage to the tail. He stated that he did not have a good view of any part of the tail. It seemed as though the airplane was flying without any problems. I did not have a push to talk switch on my side so I advised the pilot to quickly request a full stop landing; Tower then cleared us to land on the runway. I returned control of the aircraft to the pilot and he made a safe landing on the runway. We came to a stop and were given a clearance by Tower to remain on the Tower frequency and to taxi back to the ramp. We knew that the door was in a field outside the airport perimeter but did not know the aircraft sustained any other damage at this point. We taxied in via the instruction given by Tower. Once reaching the hangar and exiting the aircraft we realized the damage it had done. The underside of the wing had roughly a two foot cut in the fabric. The fuselage just aft of the wing had two large tears/holes; one roughly one foot high by two feet long; and the other roughly one square foot. The left horizontal stabilizer was able to be moved up and down roughly a half inch in both directions. The rudder had a round hole a few inches in diameter on the left side which exited through to the right. The elevator also had a hole/tear which entered through the bottom and exited through the top. After realizing the damage to the airplane other than the door we decided we most likely needed to file a report. The pin that came off does not have a cotter pin through it; instead it uses a lock nut. The pilot said it was built according to specifications provided by manufacturer. A lock nut is not sufficient means to hold the pin in place. Luckily the door did not do more damage than it did. We would not have had time to recover at the altitude and airspeed where the incident had occurred if our control surfaces had been adversely affected.

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.