Flight Crew Commercial; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 38; Flight Crew Total 480; Flight Crew Type 200
Situational Awareness; Training / Qualification
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft; Human Factors
The purpose of this flight was to provide a joint introductory lesson for two people (an adult and a male child of 12). The Piper Warrior III had full fuel and three people on-board; but was within the weight-and-balance. The taxi to the runway and run-up was normal and consistent with prior flights in this particular aircraft. The shorter runway was in use; so a flaps-10 takeoff was performed. The takeoff roll was slow; but consistent with past performance of the aircraft at this weight. The student performed the takeoff and initial climb; assisted by me (verifying full power and proper control inputs). However; at approximately 150-250 FT AGL; it became apparent to me that our airspeed and climb rate was not normal. I took control of the aircraft from the student and attempted to level off to gain some forward speed to prevent a stall. I was only able to get about 300 FPM maximum climb rate and about 100-150 RPM short of a normal full-power climb. I informed the Tower that we would be circling back for landing; and that the engine was not producing full power. Tower asked if I wanted to declare an emergency; and I responded in the affirmative. I attempted a landing back on the departure runway; but experienced a lot of thermal lift over short final; and had to perform a go-around due to the short runway length. I then attempted a landing on the longer cross runway and was eventually able to landing without incident. Equipment was standing by upon landing; but a normal taxi back to the FBO was uneventful and emergency services were not required.A full-power run-up after deplaning was performed and the aircraft didn't exhibit any usual behavior. A possible theory for the poor performance was the near-gross-weight of the aircraft; the density altitude; and the low-performance engine. Additionally; the temperature and dew point was conducive to carb icing; so the relatively long taxi to the runway and time spent at low power could have caused some carb icing to occur. At the time I didn't attempt full troubleshooting of the engine issue given the poor performance during the climb and need to climb above rising terrain. However; the aircraft wasn't exhibiting any of the other usual signs of carb icing (the RPM was lower than expected; but it wasn't decreasing); and all other engine parameters were in their normal ranges. In the future; I will give more consideration to possible carb icing on the ground prior to takeoff; and alter my run-up procedures to include an extended test of the carb heat control to see if the RPM fluctuates at all suggesting possible icing. Use of the longer runway when wind conditions allow when at similarly high gross weights and density altitudes will also be another consideration.
A PA-28 Instructor pilot experienced poor climb performance shortly after takeoff; leading to a declaration of emergency and return to field for a safe landing. Reporter thinks that carb ice was a possibility.