Narrative:

While acting as a CFI training another pilot to be checked out at ZZZ; we experienced a partial loss of engine power immediately after executing a climb from a low approach into runway 31 at ZZZ. The other pilot; who was flying; immediately lowered the nose to maintain best glide; while using our excess airspeed and momentum to gain some altitude. We simultaneously completed all emergency checklists; and made an immediate right turn that would result in a short final approach to ZZZ1. While the turn was initiated; I contacted ZZZ1 tower; and declared an emergency; advising that we had lost some of our engine power and were going to land on runway 9. The tower controller took immediate action to instruct an aircraft on short final for runway 27 to go around on the north side of the runway; so as not to be a factor. The winds from the last reported metar were 300 degrees at 13 KTS gusting 19 KTS. At that time; I took control of the aircraft; spotted the other airplane going around; and made an uneventful landing on the runway. Tower asked if we needed a tow and any further assistance; to which I responded 'no' since we still had some engine power to make it to our hangar. This emergency had a successful outcome due to the CRM between myself and the other pilot (also a licensed CFI); efficient communication and action taken by the tower controller; immediate decision to turn toward runway 9; which was within a reachable distance; and the tailwind that increased our ground speed towards the runway to help us make it in. As a result; both myself and the other pilot experienced no injuries and the aircraft was not damaged.

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Original NASA ASRS Text

Title: C-172 EXHIBITED PARTIAL LOSS OF POWER. PLTS DECLARED EMER AND PERFORMED SUCCESSFUL EMER LNDG AT NEAREST ARPT.

Narrative: WHILE ACTING AS A CFI TRAINING ANOTHER PLT TO BE CHKED OUT AT ZZZ; WE EXPERIENCED A PARTIAL LOSS OF ENG PWR IMMEDIATELY AFTER EXECUTING A CLB FROM A LOW APCH INTO RWY 31 AT ZZZ. THE OTHER PLT; WHO WAS FLYING; IMMEDIATELY LOWERED THE NOSE TO MAINTAIN BEST GLIDE; WHILE USING OUR EXCESS AIRSPD AND MOMENTUM TO GAIN SOME ALT. WE SIMULTANEOUSLY COMPLETED ALL EMER CHKLISTS; AND MADE AN IMMEDIATE R TURN THAT WOULD RESULT IN A SHORT FINAL APCH TO ZZZ1. WHILE THE TURN WAS INITIATED; I CONTACTED ZZZ1 TWR; AND DECLARED AN EMER; ADVISING THAT WE HAD LOST SOME OF OUR ENG PWR AND WERE GOING TO LAND ON RWY 9. THE TWR CTLR TOOK IMMEDIATE ACTION TO INSTRUCT AN ACFT ON SHORT FINAL FOR RWY 27 TO GO AROUND ON THE N SIDE OF THE RWY; SO AS NOT TO BE A FACTOR. THE WINDS FROM THE LAST RPTED METAR WERE 300 DEGS AT 13 KTS GUSTING 19 KTS. AT THAT TIME; I TOOK CTL OF THE ACFT; SPOTTED THE OTHER AIRPLANE GOING AROUND; AND MADE AN UNEVENTFUL LNDG ON THE RWY. TWR ASKED IF WE NEEDED A TOW AND ANY FURTHER ASSISTANCE; TO WHICH I RESPONDED 'NO' SINCE WE STILL HAD SOME ENG PWR TO MAKE IT TO OUR HANGAR. THIS EMER HAD A SUCCESSFUL OUTCOME DUE TO THE CRM BTWN MYSELF AND THE OTHER PLT (ALSO A LICENSED CFI); EFFICIENT COM AND ACTION TAKEN BY THE TWR CTLR; IMMEDIATE DECISION TO TURN TOWARD RWY 9; WHICH WAS WITHIN A REACHABLE DISTANCE; AND THE TAILWIND THAT INCREASED OUR GND SPD TOWARDS THE RWY TO HELP US MAKE IT IN. AS A RESULT; BOTH MYSELF AND THE OTHER PLT EXPERIENCED NO INJURIES AND THE ACFT WAS NOT DAMAGED.

Data retrieved from NASA's ASRS site as of January 2009 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.