PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Flight Instructor; Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 130; Flight Crew Total 380; Flight Crew Type 80
Aircraft Equipment Problem Critical; Ground Event / Encounter Object; Inflight Event / Encounter Object
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition
Aircraft
Just took off...reached 2500 feet and leveled off. Around half way or 3/4 way over [the adjacent] Bay my engine rpm decreased from 2200rpm to 1300rpm. I took controls from students and pitch for Vg. I searched for a field across the bay. I could easily make it to land but there were only trees on the shore. So I turned heading south to line up with the coast and got as close to shore as possible. I [advised] Approach...and I squawked 7700. After my second restart the engine gave me 1800-2000rpm. If I pulled the throttle out an inch or less and push it back in for full throttle the engine would give me 2000-2100rpm. So I consistently was pulling the throttle out an inch and pushing it back in. I made a quick decision to aim for a field that I believed I could make. I headed to the field. I came to the realization I was going to fall short. I deployed my first notch of flaps; 10 degrees to create more lift. As I approached the field I deployed my second notch; 25 degrees. Around 800 ft msl the engine rpm fell to 1300rpm. I knew I had the field made and deployed 3rd notch; 40degrees. I landed on the field and ran through a barbed wire fence. We came to a complete stop just after the fence.
When the power dropped precipitously as they were crossing a bay near their departure airport the instructor and student pilots aboard a PA-28 established best glide speed and nursed the aircraft to a safe landing in a field where their rollout was arrested by a barbed wire fence.