Narrative:

Student and I were performing touch and goes. On the upwind of a touch and go we noticed that the manifold pressure gauge was reading atmospheric pressure no matter the throttle position. The engine was still performing normally but we decided to make the next landing a full stop. I took the controls momentarily on the start of the downwind so that the student could tap the gauge. We exchanged controls again and requested a full stop. We were performing short approaches and got clearance for another short approach. The student reduced throttle (the manifold gauge still read atmospheric pressure) and selected flaps to 20 degrees. We touched down gear up on 28L; which is the runway we were cleared for; the student added power and I took controls and put the gear down. As I climbed out; tower was notified immediately by an aircraft in the runup area for 28L of what had just occurred. Tower asked if we needed any assistance. The plane was flying normally so we declined; obtained a clearance to land and flew the pattern. I flew the aircraft; performed a soft field landing and taxied back. Upon shut down it was revealed that the prop did strike the ground. There were several human factors involved. I; the instructor; have been teaching now for just over three years with over 1;000 hours of dual given time. I can say that I have become complacent in my teaching at times which has degraded my once prided professional manner with which I taught. Also; I have had a lot going on at home with a new baby as well as being the sole provider for my family has put some additional stress on me. I have also been very busy with other personal and professional obligations which have stretched my attention and energy. I failed to verify that the gear was down with my own bgumps checklist. I also relied on the aircraft too much to warn us that the gear was down but due to the fact that the manifold pressure was at atmospheric level and the flaps were only at 20 the horn did not go off. The cause of the prop strike was lack of checklist usage; lack of communication during the exchange of controls of the state of the aircraft; fixation on the inoperative instrument; complacency by me; and failure to verify that the gear was down. Re-currency training of both flight and ground as well as being aware of a complacent mindset can be used to prevent this from happening in the future. Also; we should have notified tower of the manifold pressure situation. It might have slowed us down in the cockpit as well as drawn attention to us by the tower who may have notified us that our gear was still up.

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Original NASA ASRS Text

Title: An instructor pilot and his student reacted quickly and initiated a rejected landing and go around when their C-172RG touched down lightly on its belly with the nose high. A safe landing followed after which they learned that they had suffered a prop strike during the event. A contributing factor was an apparently failed manifold pressure gauge which distracted both pilots from checklist SOPs.

Narrative: Student and I were performing touch and goes. On the upwind of a touch and go we noticed that the manifold pressure gauge was reading atmospheric pressure no matter the throttle position. The engine was still performing normally but we decided to make the next landing a full stop. I took the controls momentarily on the start of the downwind so that the student could tap the gauge. We exchanged controls again and requested a full stop. We were performing short approaches and got clearance for another short approach. The student reduced throttle (the manifold gauge still read atmospheric pressure) and selected flaps to 20 degrees. We touched down gear up on 28L; which is the runway we were cleared for; the student added power and I took controls and put the gear down. As I climbed out; Tower was notified immediately by an aircraft in the runup area for 28L of what had just occurred. Tower asked if we needed any assistance. The plane was flying normally so we declined; obtained a clearance to land and flew the pattern. I flew the aircraft; performed a soft field landing and taxied back. Upon shut down it was revealed that the prop did strike the ground. There were several human factors involved. I; the instructor; have been teaching now for just over three years with over 1;000 hours of dual given time. I can say that I have become complacent in my teaching at times which has degraded my once prided professional manner with which I taught. Also; I have had a lot going on at home with a new baby as well as being the sole provider for my family has put some additional stress on me. I have also been very busy with other personal and professional obligations which have stretched my attention and energy. I failed to verify that the gear was down with my own BGUMPS checklist. I also relied on the aircraft too much to warn us that the gear was down but due to the fact that the manifold pressure was at atmospheric level and the flaps were only at 20 the horn did not go off. The cause of the prop strike was lack of checklist usage; lack of communication during the exchange of controls of the state of the aircraft; fixation on the inoperative instrument; complacency by me; and failure to verify that the gear was down. Re-currency training of both flight and ground as well as being aware of a complacent mindset can be used to prevent this from happening in the future. Also; we should have notified Tower of the manifold pressure situation. It might have slowed us down in the cockpit as well as drawn attention to us by the Tower who may have notified us that our gear was still up.

Data retrieved from NASA's ASRS site as of July 2013 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.