Narrative:

I was acting PIC of a multi-engine instructional flight when; the nose gear of the aircraft failed to extend; caused by a mechanical fracture of the nose gear actuator piston rod. Weather conditions reported by metar at the time were variable winds at 4 KTS; 10 statute miles of visibility; scattered clouds at 4;900 feet AGL; temperature 24 C; dew point 11; and altimeter setting of 30.19' hg. Runway conditions were dry.on every approach; upon passage of the final approach fix; the landing gear was successfully extended. Part of standardization that day was to reinforce the importance of keeping one hand on the gear selector knob until verification of gear down by three green lights. On the first four approaches; it was verified that all three landing gear were down and locked. Upon passage of the final approach fix; I noted that the nose gear indicator light did not illuminate. At that time we had begun our descent to minimums. I did not want to continue the descent; so we leveled off at approximately 1;500 feet. I took the controls of the aircraft and advised tower that we did not have a safe gear down situation. I cycled the gear; and the nose wheel indicator still did not illuminate. This was followed by three more cycles; none of which produced any change. My next step was to see if the nose gear light was burnt out by exchanging it with an operable light of a different gear. However; the lights on this aircraft were not the type to be easily replaced in flight. I then requested a low approach for the tower to take a look at our nose gear. Permission was granted. After passage directly in front of the tower at 500 feet MSL (350 feet AGL) they informed me that the nose gear 'appeared to be down.' my thought then was that it probably was down; but that we should use the manual gear extension knob to supply pressure to the gear in the case it was not completely locked. I instructed my student to pump the gear 35-40 times with the gear selector knob down; as called for in the aircraft's information manual. I also extended my upwind an additional mile or two. During that time; my student finished the manual gear pumping; and reported that there was hardly any resistance to his force on the selector; nor had the pressure changed as a result of his pumping. I cycled the gear one more time and checked the resistance to pressure myself. Indeed; there was hardly any resistance at all.by this point; I made the turn back for the left downwind; and concluded that: 1) the gear was down and locked; and the problem was electrical; or 2) the gear was down; but not locked; due to mechanical failure; and any cycling or manual extending would not solve anything. Thus; I made the decision that I would attempt to land the airplane. By this point; we were midfield on the downwind; and I knew a co-worker of mine with experience in this aircraft was in the traffic pattern. I advised him directly over tower frequency of the steps I had performed; to which he responded that I had done all correctly. Tower had already cleared me for the option; but I advised them it would be a full stop; and that we may be having a gear up landing. I planned for a soft field landing. As I brought the airplane in over the runway at 100 feet AGL; I slowed the descent rate; and prolonged the airplane flare as long as I could some five feet above the ground with the nose up; thereby reducing speed and minimizing the force that would ensue upon nose wheel contact with the ground. Per my request; my students hand was on the mixture levers; and the instant I noticed that the nose wheel would collapse; I told him; 'cutoff;' which he did. We then skidded down the runway some 500 feet before coming to a stop. We secured all switches inside the aircraft and then exited immediately. I called the tower on my cell phone to advise them we were okay.

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Original NASA ASRS Text

Title: Light twin instructor pilot experiences an unsafe nose gear indication during approach and goes around to investigate. All attempts at achieving a safe indication are unsuccessful and upon landing the nose gear collapses.

Narrative: I was acting PIC of a multi-engine instructional flight when; the nose gear of the aircraft failed to extend; caused by a mechanical fracture of the nose gear actuator piston rod. Weather conditions reported by METAR at the time were variable winds at 4 KTS; 10 statute miles of visibility; scattered clouds at 4;900 feet AGL; temperature 24 C; dew point 11; and altimeter setting of 30.19' Hg. Runway conditions were dry.On every approach; upon passage of the final approach fix; the landing gear was successfully extended. Part of standardization that day was to reinforce the importance of keeping one hand on the gear selector knob until verification of gear down by three green lights. On the first four approaches; it was verified that all three landing gear were down and locked. Upon passage of the final approach fix; I noted that the nose gear indicator light did not illuminate. At that time we had begun our descent to minimums. I did not want to continue the descent; so we leveled off at approximately 1;500 feet. I took the controls of the aircraft and advised Tower that we did not have a safe gear down situation. I cycled the gear; and the nose wheel indicator still did not illuminate. This was followed by three more cycles; none of which produced any change. My next step was to see if the nose gear light was burnt out by exchanging it with an operable light of a different gear. However; the lights on this aircraft were not the type to be easily replaced in flight. I then requested a low approach for the tower to take a look at our nose gear. Permission was granted. After passage directly in front of the Tower at 500 feet MSL (350 feet AGL) they informed me that the nose gear 'appeared to be down.' My thought then was that it probably was down; but that we should use the manual gear extension knob to supply pressure to the gear in the case it was not completely locked. I instructed my student to pump the gear 35-40 times with the gear selector knob down; as called for in the aircraft's information manual. I also extended my upwind an additional mile or two. During that time; my student finished the manual gear pumping; and reported that there was hardly any resistance to his force on the selector; nor had the pressure changed as a result of his pumping. I cycled the gear one more time and checked the resistance to pressure myself. Indeed; there was hardly any resistance at all.By this point; I made the turn back for the left downwind; and concluded that: 1) The gear was down and locked; and the problem was electrical; or 2) the gear was down; but not locked; due to mechanical failure; and any cycling or manual extending would not solve anything. Thus; I made the decision that I would attempt to land the airplane. By this point; we were midfield on the downwind; and I knew a co-worker of mine with experience in this aircraft was in the traffic pattern. I advised him directly over Tower frequency of the steps I had performed; to which he responded that I had done all correctly. Tower had already cleared me for the option; but I advised them it would be a full stop; and that we may be having a gear up landing. I planned for a soft field landing. As I brought the airplane in over the runway at 100 feet AGL; I slowed the descent rate; and prolonged the airplane flare as long as I could some five feet above the ground with the nose up; thereby reducing speed and minimizing the force that would ensue upon nose wheel contact with the ground. Per my request; my students hand was on the mixture levers; and the instant I noticed that the nose wheel would collapse; I told him; 'CUTOFF;' which he did. We then skidded down the runway some 500 feet before coming to a stop. We secured all switches inside the aircraft and then exited immediately. I called the Tower on my cell phone to advise them we were okay.

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.