Rough Climb Out of Tampa Bay
Partial power loss in a marginal-climb airplane over dense development — carburetor ice, decision-making, and the limits of the Cessna 150M
The scenario
Departing Tampa International Airport (KTPA), Tampa, FL — Runway 10, climbing out on a 092° heading. Elevation 26 ft MSL. The runway is essentially at sea level; the off-field environment on the climb-out is dense development, open developed areas (parks, large lots), and wooded wetland — marginal forced-landing terrain.
It is a warm, humid Florida morning in late spring: OAT 27°C, dew point 21°C, altimeter 29.91. Scattered clouds at 2,800 ft, light rain shower two miles to the east. Visibility 9 SM. The relative humidity is 75% — classic Gulf Coast conditions that the FAA icing probability chart marks as 'serious icing at glide power, moderate icing at cruise power.' You are in Class B airspace; KTPA tower is active 24/7.
You are 500 ft AGL, climbing through 68 KIAS (Vy, best rate of climb), heading 092°, when the engine begins to run rough. Power is noticeably down — the tachometer is unwinding. The Cessna 150M is a marginal-climb airplane at gross weight; you are carrying full fuel and two adults near maximum gross. The climb rate is already modest. Now it is worse.
Aircraft: Cessna 150M, two adults, full fuel, within limits. Continental O-200-A, 100 hp, carbureted, fixed-pitch prop, steam panel, fuel selector on BOTH. Nothing was written up; the airplane was airworthy at departure.
Pilot: you — a Private pilot, current, roughly 250 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 the tower frequency.
- {'label': 'Field', 'value': 'KTPA · Tampa'}
- {'label': 'Runways', 'value': '10/28 · 19L/01R · 19R/01L'}
- {'label': 'Elevation', 'value': '26 ft'}
- {'label': 'Aircraft', 'value': 'C150'}
- {'label': 'Dominant phase', 'value': 'Landing / Takeoff'}
The decision
Before we get into the decision tree — what do you already know about carburetor ice in the C150M? (Pick all that apply; this records your baseline.)
What the record shows
What the NTSB files show
NTSB ERA25LA028 (2024): A Cessna 150H encountered carburetor ice at cruise altitude in conditions with 100% relative humidity. The engine ran rough and lost power. The probable cause was carburetor ice formation in conditions conducive to serious icing, with insufficient time and altitude for carburetor heat to clear the accumulated ice. The pilot had not applied carburetor heat proactively in conditions that clearly warranted it.
NTSB ANC25LA005 (2024): A Cessna 150 on a personal flight experienced partial engine power loss due to carburetor ice during initial climb in 70% relative humidity — well below saturation, but still conducive to serious icing at glide power. The probable cause was the pilot's improper use of carburetor heat while operating on Mogas in icing conditions.
NTSB ERA24LA087 (2024): A Cessna 150M on a solo cross-country instructional flight experienced partial engine power loss due to carburetor icing when the student pilot failed to apply carburetor heat. The accident resulted in a forced landing and a runway excursion — the pilot failed to attain a proper touchdown point during the diversionary landing.
NTSB CEN21LA381 (2021): A Cessna 150 experienced partial engine power loss due to carburetor icing during takeoff near Wadsworth, Ohio, when the pilot failed to apply carburetor heat despite conditions in the moderate-to-serious icing range. The pilot made a forced landing to a corn field where the aircraft nosed over.
NTSB CEN23FA401 (2023, FATAL): A Cessna 150K on an instructional flight experienced partial engine power loss due to fuel system blockage and subsequently stalled during a descending left turn at low altitude. The flight instructor failed to maintain adequate airspeed after the power loss. The accident was fatal.
The real accidents cited above occurred at other airports and in other C150 variants — NOT at Tampa International Airport. KTPA has its own accident history (see field dominant patterns), but these specific events happened elsewhere. The scenario is localized to KTPA to make the off-field environment real and consequential for you as a student here.
The consistent thread across all these events: carburetor ice in the C150M is insidious. It 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.
At KTPA, the off-field environment on the Runway 10 departure is dense development with open developed areas (parks, large lots) — marginal forced-landing terrain. A C150M at gross weight with partial power loss at 500 ft AGL has no good options ahead. The decision to apply carb heat immediately, or to turn back to the airport, must be made within seconds. There is no time for diagnosis or delay.
Key lesson — In warm, moist Gulf Coast air, the C150M's carbureted Continental O-200-A 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 dense development, the decision window is measured in seconds — not minutes. The C150M is a marginal-climb airplane at gross weight; a partial power loss at 500 ft AGL is a serious emergency. Early recognition and immediate action are the only margin you have.
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 Gulf Coast afternoon conditions at KTPA. You do not need visible ice, freezing temperatures, or IMC. Warm, moist air at reduced power is the classic carb-ice environment. The C150M's Continental O-200-A is carbureted; it has no alternate air system. Carburetor heat is the only tool. At 27°C and 75% relative humidity, you are in the serious icing range at glide power.
The first symptom is subtle — a dropping tachometer and engine roughness.
In a fixed-pitch airplane like the C150M, 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. The C150M is a marginal climber; a 200 RPM loss is a big deal.
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 C150M is a marginal-climb airplane at gross weight, especially in heat and high density altitude.
At KTPA (elevation 26 ft MSL) on a warm morning with two adults and full fuel, the C150M's climb performance is modest — roughly 400–500 fpm at best. A partial power loss at 500 ft AGL is a serious emergency. You do not have the altitude margin to troubleshoot or delay. The decision to apply carb heat immediately, or to turn back to the airport, must be made within seconds. Understand your airplane's climb performance before you depart; it determines your decision window in an emergency.
Proactive carb heat use in conducive conditions is not optional.
The C150M 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 Gulf Coast summer departure with OAT near 27°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 500 ft AGL over dense development is waiting too long.
Off-field environment drives your decision-making.
The off-field environment off Runway 10 at KTPA is dense development with open developed areas (parks, large lots) — marginal forced-landing terrain. There is no open field, no water, no clear area. If the engine fails on the Runway 10 departure at low altitude, your options are limited to turning back to the airport or landing in dense development. This geographic reality shapes your decision window and your tolerance for risk. Know the off-field environment before you depart; it determines your go-or-divert and your emergency response.
Built from the real accident record
Scenario built from NTSB ERA25LA028, ANC25LA005, ERA24LA087, WPR21LA329, CEN21LA381, ERA21LA284, CEN23FA401, and CEN23FA077 — all Cessna 150-series carburetor ice and partial power loss events. Real accidents occurred at other airports and in other C150 variants. Localized to KTPA.
NTSB reports: ERA25LA028 · ANC25LA005 · ERA24LA087 · WPR21LA329 · CEN21LA381 · ERA21LA284 · CEN23FA401 · CEN23FA077
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.
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