Rough Climb Over Pasco County
Partial power loss on departure from Zephyrhills — carburetor ice, fuel management, and a low-altitude decision in a Piper Warrior
The scenario
Departing Zephyrhills Municipal Airport (KZPH), Pasco County, FL — Runway 01, climbing out on a 010° heading into a warm, humid Florida morning. Elevation 90 ft MSL; the runway is essentially at sea level.
It is a hazy late-spring morning: OAT 26°C, dew point 21°C, altimeter 29.94. Scattered clouds at 2,800 ft, light rain shower visible to the northeast. Visibility 9 SM. The conditions are classic for carburetor icing in a carbureted Lycoming O-320: warm air, high moisture, and reduced power on climb. The FAA icing probability chart marks this as 'serious icing at glide power, moderate icing at cruise power.'
You are 350 ft AGL, climbing through 79 KIAS (Vy, best rate of climb), heading 010°, when the engine begins to run rough. Power is noticeably down — the tachometer is dropping. The off-field environment ahead is mostly pasture, hay, and open developed areas (parks/large lots) — good forced-landing terrain. KZPH is non-towered (CTAF); you are in Class G airspace.
Aircraft: Piper PA-28-161 Warrior, solo, full fuel, within limits. Carbureted Lycoming O-320, fixed-pitch prop, steam panel, fuel selector on LEFT tank. Nothing was written up; the airplane was airworthy at departure.
Pilot: you — a Private pilot, current, roughly 180 hours total. You did not apply carburetor heat during the run-up because the engine ran smoothly. You did not apply it after takeoff because you were focused on the climb and did not notice the early roughness until the power loss was obvious.
- {'label': 'Field', 'value': 'KZPH · Zephyrhills'}
- {'label': 'Runways', 'value': '19/1 · 5/23'}
- {'label': 'Elevation', 'value': '90 ft'}
- {'label': 'Aircraft', 'value': 'PA-28-161'}
- {'label': 'Dominant phase', 'value': 'Landing / Cruise'}
The decision
Before we get into the decision tree — what do you already know about carburetor ice in the PA-28-161 Warrior and fuel management in this airplane? (Pick all that apply; this records your baseline.)
What the record shows
What the NTSB files show
NTSB CEN12LA175 (2012): A Piper PA-28-161 on an instrument instructional flight experienced progressive engine power loss due to carburetor icing during climb through 6,500 feet. The probable cause was carburetor icing in conditions conducive to serious icing, with a contributing factor of limited carburetor heat valve travel from recent maintenance. The lesson: even a properly functioning carb heat system can be compromised by maintenance errors, and the pilot must recognize icing symptoms early.
NTSB LAX03LA238 (2003): A Piper PA-28-161 experienced partial engine power loss during initial climb from Torrance due to carburetor icing. During a go-around attempt, the pilot failed to maintain adequate airspeed, resulting in a stall and collision with power lines and terrain. The probable cause was carburetor icing and the pilot's failure to use carburetor heat. The lesson: partial power loss is not an excuse to abandon airspeed discipline — stalling at low altitude is fatal.
NTSB CHI05LA226 (2005, fatal): A Piper PA-28-161 on an instructional flight lost engine power due to left magneto failure during initial climb after takeoff and subsequently stalled. The probable cause was partial magneto failure caused by improper maintenance, with contributing factors including the instructor's failure to maintain airspeed and follow emergency procedures. The lesson: magneto failure is rare but possible; airspeed discipline is non-negotiable.
NTSB ERA14LA141 (2014): A Piper PA-28-161 experienced partial engine power loss during takeoff from Atlantic City International Airport and the pilot executed a forced landing to the airport perimeter road. The accident resulted from a partial loss of engine power for reasons that could not be determined during postaccident examination. The lesson: sometimes the cause is unknowable, but the response — immediate descent to the best available landing surface — is always the same.
The local environment at KZPH makes this scenario survivable: Runway 01's climb-out environment is mostly pasture, hay, and open developed areas (parks/large lots) — good forced-landing terrain. An engine failure on the Runway 01 departure at low altitude is a forced landing in soft ground, not a ditching or a collision with structures. This is not hypothetical; it is the USGS NLCD ground cover off that runway end. The real accidents cited above occurred at other airports and in other aircraft — NOT at Zephyrhills Municipal Airport.
The consistent thread across all these events: partial power loss in a PA-28-161 is insidious. Carburetor icing builds gradually, the first symptom is roughness and a dropping tachometer (not a dramatic power cut), and by the time it is obvious, it may be too late for a comfortable recovery. The fix — full carburetor heat, immediately, at the first sign of roughness in conducive conditions — is simple. The failure is always a delay. And in a PA-28-161, fuel management (LEFT/RIGHT selector, no BOTH position) adds a second layer of complexity: a pilot who is distracted by a rough engine may forget to monitor fuel flow and inadvertently starve the engine by not switching tanks.
Key lesson — In warm, moist Florida air, the PA-28-161's carbureted O-320 can accumulate serious carburetor ice even at cruise power and above-freezing temperatures. Apply full carburetor heat at the first sign of engine roughness or unexplained RPM loss. At low altitude over good off-field terrain, the decision window is measured in seconds — not minutes. Off Runway 01 at KZPH, the off-field environment is pasture/hay/open developed areas: a forced landing there is survivable. The real risk is delay, stalling, or trying to stretch a glide to the runway.
Debrief — teaching points
Carburetor ice forms in conditions you would not expect.
The FAA icing probability chart shows 'serious icing at glide power' at temperatures between roughly 20°C and 30°C when relative humidity is high — exactly the Florida morning conditions at KZPH. You do not need visible ice, freezing temperatures, or IMC. Warm, moist air at reduced power is the classic carb-ice environment. The PA-28-161's Lycoming O-320 is carbureted; it has no fuel injection or alternate air system. Carburetor heat is the only tool.
The first symptom is subtle — a dropping tachometer and engine roughness.
In a fixed-pitch airplane like the PA-28-161, carburetor ice first shows as engine roughness and an unexplained RPM decrease. There is no dramatic power cut. Pilots who are not actively monitoring the tachometer miss the early warning. By the time the roughness is obvious, significant ice has accumulated. Scan the tachometer as part of your regular instrument scan, especially in conducive conditions.
Apply full carburetor heat — not partial — and expect an initial RPM drop.
When you apply carb heat to an iced carburetor, the RPM will drop further before it rises. This is expected and normal: the heat is melting ice and the resulting water is briefly disrupting combustion. Do not remove carb heat when the RPM drops — that is the heat working. Hold it full on. The RPM will recover as the ice clears, typically within 15–30 seconds depending on ice accumulation. Partial carb heat can worsen the situation by partially melting ice into water ingestion without fully clearing the restriction.
The PA-28-161 has a LEFT/RIGHT fuel selector with NO BOTH position — manage it actively.
Unlike some Cessnas, the Piper Warrior has no BOTH position on the fuel selector. You must actively switch tanks to avoid fuel starvation from running one tank dry. In an emergency (rough engine, low altitude), fuel management can be forgotten. Establish a habit: switch tanks every 30 minutes of flight, and always know which tank is feeding. If the engine roughens and carb heat does not fix it, fuel starvation is the second diagnostic — switch tanks immediately.
At KZPH Runway 01, an engine failure on departure is a forced landing in good terrain.
The off-field environment off Runway 01's departure end (heading 010°) is mostly pasture, hay, and open developed areas (parks/large lots) — good forced-landing terrain. There is no water, no dense development, no obstacles. If the engine quits on the Runway 01 departure and altitude is insufficient to return to the airport, the outcome is a controlled forced landing in soft ground. This is survivable. Best glide is 73 KIAS. Fuel selector on the feeding tank. Master off just before touchdown. Flaps for slowest possible touchdown speed — impact energy rises with the square of touchdown speed, so the slowest possible speed matters most. Know this before you line up on Runway 01.
Proactive carb heat use in conducive conditions is not optional.
The PA-28-161 POH and the FAA Pilot's Handbook of Aeronautical Knowledge both recommend applying carburetor heat when conditions are conducive to icing — before the symptom appears. In a Florida morning departure, with OAT near 26°C and dew point near 21°C, that means applying carb heat during the run-up check (and confirming the expected RPM drop, then recovery) and considering its use during climb in visible moisture or high humidity. Waiting for the roughness to appear at 350 ft AGL over Pasco County is waiting too long.
Built from the real accident record
Scenario built from NTSB CEN12LA175 (2012 PA-28-161 carburetor ice / power loss on climb), LAX03LA238 (2003 PA-28-161 carb ice / stall on go-around), CHI05LA226 (2005 PA-28-161 magneto failure / stall on climb), ERA14LA141 (2014 PA-28-161 partial power loss on takeoff), and related PA-28-161 accident precedents. Localized to Zephyrhills Municipal Airport (KZPH), Florida.
NTSB reports: CEN12LA175 · LAX03LA238 · CHI05LA226 · ERA14LA141 · WPR10FA264 · CHI08LA197 · IAD05LA133 · DEN03LA139
ACS tasks: PA.I.F — Weather Information · PA.I.G — Cross-Country Flight Planning · PA.IX.C — Emergency Approach and Landing · PA.I.H — Human Factors · PA.II.B — Engine Starting / Systems Preflight
Relevant FARs: §91.3 · §91.13 · §91.185
Step through the full decision tree, make the calls, and see where each choice leads — then debrief it with your CFI.
Open the interactive scenario →All sample scenarios · More Piper Warrior scenarios · More scenarios at KZPH