A C172 instructor reported his student lost control of the aircraft while practicing short field tak...

Narrative:

My student was practicing a soft field take off. He had the yoke all the way back; and I could only see out the right window. I noticed we were getting farther and farther from the center line. I mentioned it to him a few times; but he did not correct; and while I knew we were not on the center line; I did not realize how close we were to the left edge of the runway; as I could only see out the right side of the airplane. I waited too long to take the controls. I applied right rudder at the same time as we ran off the left side of the runway; and our main wheels lifted off the ground almost immediately after. My student banked the airplane hard to the right to try to get us back to the center line. We were in a steep bank; and when I got the airplane level; we had flown over to the right side of the runway (though we did not have nearly enough airspeed to climb out of ground effect). We landed the airplane on the grass on the right side of the runway. The tower asked if we were alright; and they asked if we could taxi the airplane back onto the movement area. We were able to do so; and we taxied back to the ramp. Tower asked us to call and let them know if there was any damage to the airplane. After parking; we walked around the airplane and found no damage. I called the tower; and told them there was none. Somebody from the airport authority stopped by to let us know that there had been absolutely no damage to any of the airport property; even the grass where we had landed looked untouched. After a long talk with the flight school's chief pilot; we went to inspect the airplane again. This time; we noticed the right wing tip was scraped and cracked. It apparently struck the runway during the steep bank immediately after liftoff. The obvious cause of the problem was that I was too slow to correct my student's error; and that my student was not paying attention to the runway center line. To prevent a recurrence; I will be much more assertive and quick to correct my student's errors. Also; on soft field takeoffs; I will make sure my students only pull the yoke back enough to get the weight off the nose wheel. This way; I will always be able to see what is ahead and on both sides of us.

Original NASA ASRS Text

Title: A C172 Instructor reported his student lost control of the aircraft while practicing short field takeoff; and he was slow to take over. They scraped a wingtip and landed off the side of the runway.

Narrative: My student was practicing a soft field take off. He had the yoke all the way back; and I could only see out the right window. I noticed we were getting farther and farther from the center line. I mentioned it to him a few times; but he did not correct; and while I knew we were not on the center line; I did not realize how close we were to the left edge of the runway; as I could only see out the right side of the airplane. I waited too long to take the controls. I applied right rudder at the same time as we ran off the left side of the runway; and our main wheels lifted off the ground almost immediately after. My student banked the airplane hard to the right to try to get us back to the center line. We were in a steep bank; and when I got the airplane level; we had flown over to the right side of the runway (though we did not have nearly enough airspeed to climb out of ground effect). We landed the airplane on the grass on the right side of the runway. The Tower asked if we were alright; and they asked if we could taxi the airplane back onto the movement area. We were able to do so; and we taxied back to the ramp. Tower asked us to call and let them know if there was any damage to the airplane. After parking; we walked around the airplane and found no damage. I called the Tower; and told them there was none. Somebody from the Airport Authority stopped by to let us know that there had been absolutely no damage to any of the airport property; even the grass where we had landed looked untouched. After a long talk with the Flight School's Chief Pilot; we went to inspect the airplane again. This time; we noticed the right wing tip was scraped and cracked. It apparently struck the runway during the steep bank immediately after liftoff. The obvious cause of the problem was that I was too slow to correct my student's error; and that my student was not paying attention to the runway center line. To prevent a recurrence; I will be much more assertive and quick to correct my student's errors. Also; on soft field takeoffs; I will make sure my students only pull the yoke back enough to get the weight off the nose wheel. This way; I will always be able to see what is ahead and on both sides of us.

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.

Attributes
ACN	894396
Time
Date	201006
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Route In Use	None
Flight Plan	None
Person 1
Function	Instructor
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 190 Flight Crew Total 875 Flight Crew Type 550
Events
Anomaly	Ground Event / Encounter Ground Strike - Aircraft Ground Excursion Runway Inflight Event / Encounter Loss Of Aircraft Control

A C172 instructor reported his student lost control of the aircraft while practicing short field takeoff; and he was slow to take over. They scraped a wingtip and landed off the side of the runway.