Cheetah; Tiger; Traveler AA5 Series
Flight Crew Private
Flight Crew Last 90 Days 15; Flight Crew Total 110; Flight Crew Type 1
Situational Awareness; Fatigue; Human-Machine Interface; Training / Qualification
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Took Evasive Action; Flight Crew Regained Aircraft Control
Aircraft; Human Factors; Procedure
My CFI and I were performing an aircraft checkout in a Grumman AA5A. One portion of the aircraft checkout consisted of power-off stalls. As most (~95%) of my flight experience is in Piper Cherokee aircraft; my experience and training for power-off stalls were all performed in Piper Cherokee aircraft; which are considerably more forgiving than the Grumman AA5A Cheetah. Compared to the Piper Cherokee; the Grumman AA5A is noticeably more sensitive in terms of aileron and elevator input. Typically; when performing a power-off stall in the Piper Cherokee; small amounts of left or right aileron input will not cause the aircraft to enter significantly uncoordinated flight; in my experience. The last time I had performed power-off stalls in a Piper Cherokee aircraft was approximately three weeks prior; in a Piper Archer aircraft; I performed to power-off stalls to my CFI's satisfaction. Prior to this; the last time I had performed a power-off stall was about 6 months prior.Up until this point on this particular flight; my CFI had been relatively 'hands-off'; he was working the radios; while I was doing the flying. My CFI and I have about 20 hours of flying time together; and this CFI signed my endorsement for my Private Pilot checkride approximately 7 months prior.As we performed the first power-off stall; I asked my CFI a question about the carburetor heat setting I should be using in this aircraft; when performing a power-off stall. At this point; the stall warning was activated; however; I had noticed it is particularly sensitive; as the stall horn had also activated on rotation; even though we had rotated at 65 knots; while the POH recommends 52 knots. As I asked my CFI this question; my airspeed was 60 knots and gradually dropping. I had expected the aircraft to stall at approximately 50 knots; at the bottom of the green arc on the airspeed indicator. However; at this point (at approximately 58 knots); the aircraft had a 'clean break' and the right wing dropped in the ensuing stall. Unlike the Piper Cherokee; which stalls without a 'clean break' and is more sluggish at high angles of attack with little aileron authority; the Grumman still had normal aileron authority; due to 'stall bars' installed on the leading edge of the wing. At this point; I turned the yoke approximately 10 degrees to the right; inputting some right aileron; subconsciously. I suspect this is a bad habit I carried over from the Piper Cherokee; that was never corrected due to the lack of aileron authority during stalls in the Piper Cherokee. As a result of the asymmetric drag now being produced; with the right-wing producing less lift than the left wing; the aircraft entered a spin. As a result of the stall; the aircraft was at an approximately 60 degree nose down attitude; and papers began to fly to the back of the cabin. The aircraft was also turning to the right; as a result of the spin. At this point; I had recognized the spin; and began to use the P.A.R.E. acronym (power idle; ailerons neutral; rudder opposite direction of spin; elevator forward) to recover. My power was set to idle and as I began to hold the ailerons neutral; my CFI yelled 'I have control' and finished the spin recovery process. As my CFI took control; I looked outside the window; and could no longer see the horizon; only the Earth below; rotating. As we leveled off; our altitude was 2;100 feet; the aircraft entered a stall at approximately 2;700 feet. It took the aircraft approximately 15 seconds to descend approximately 900 feet. Had my CFI not recovered in time; the aircraft would have likely impacted the ground within 30 seconds from an altitude of approximately 2;100 feet. One leading contributor to the incident was my fixation on the turn coordinator. As I had fixated on the 'ball' in the turn coordinator; keeping the aircraft in near-perfect coordinated flight; when the aircraft stalled; I was not expecting the stall at that moment; and was not looking outsideto notice the wing dropping before I had inadvertently inputted right aileron. Another contributor to this incident was my sleep deprivation. I had not flown in the past three weeks; and was not expecting to fly on that day; however; that morning I had noticed the weather had improved to near-perfect VFR flight conditions; unexpectedly; and decided to fly that day. However; the night before I had slept for approximately 3 hours and 30 minutes; leading to fatigue. While I would not have gone flying as pilot-in-command with that level of sleep deprivation; I had figured I would be safe flying with a well-rested CFI. In summary; this stall-spin scenario could have been avoided by following the '90% out; 10% in' rule to avoid fixating on the turn coordinator; recognizing the specific handling characteristics of this aircraft prior to practicing the power-off stall; and paying closer attention to the position of the yoke with regard to aileron input. I performed four additional power-off stalls in addition to two power-on stalls to my CFI and I's satisfaction.
GA pilot reported entering a spin while practicing stalls in an unfamiliar aircraft; which had unexpected stall characteristics.