Rough Air Over Tampa Executive
Carburetor ice, partial power loss, and a low-altitude decision — the C150's marginal climb performance makes every second count
The scenario
Departing Tampa Executive Airport (KVDF), Tampa, FL — Runway 05, climbing out on a 042° heading. Elevation 22 ft MSL. It is a humid Florida morning in late spring: OAT 26°C, dew point 21°C, altimeter 29.94. Scattered clouds at 2,800 ft, light rain shower one mile to the northeast. Visibility 9 SM. The conditions are textbook for carburetor icing in a carbureted airplane — warm, moist air, and the temperature/dew point spread is in the serious icing range at glide power.
You are 350 ft AGL, climbing through 68 KIAS (Vy, best rate of climb), heading 042°, when the engine begins to run rough. Power is noticeably down — the tachometer is dropping. The climb rate is flattening. Off Runway 05's departure end (heading 042°), the off-field environment is wooded wetland and pasture — not ideal, but landable. KVDF is non-towered (CTAF); you are in Class G airspace below 3,000 ft MSL. Above 3,000 ft MSL, you would enter the overlying Tampa Class B airspace.
Aircraft: Cessna 150M, solo, full fuel, within limits. Continental O-200-A, 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 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 tachometer beginning to drift down until the roughness became obvious.
- {'label': 'Field', 'value': 'KVDF · Tampa Executive'}
- {'label': 'Runways', 'value': '5/23 · 18/36'}
- {'label': 'Elevation', 'value': '22 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 and a temperature/dew point spread conducive to serious icing. The engine ran rough and lost power. The probable cause was carburetor ice formation with the pilot's delayed use of carburetor heat. 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 conditions with 70% relative humidity 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 pilot made a diversionary landing but failed to attain a proper touchdown point, resulting in a runway excursion. The lesson: carburetor heat first, then manage the 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. The pilot survived.
NTSB ERA21LA284 (2021): A Cessna 150 instructional aircraft lost engine power during takeoff due to carburetor icing and made a forced landing into trees. The accident resulted from carburetor ice formation under atmospheric conditions conducive to serious icing at glide power, with insufficient time to melt accumulated ice despite carburetor heat application. The lesson: early application of carb heat is critical.
NTSB CEN23FA401 (2023, FATAL): A Cessna 150K on an instructional flight practicing touch-and-go landings 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 lesson: after any power loss, establish best glide speed immediately — do not try to stretch the glide or turn aggressively.
NTSB CEN23FA077 (2023, FATAL): A Cessna 150H on an instructional flight conducted a night visual approach to a non-towered airport in dark conditions. The aircraft descended below safe altitude and impacted a farm field 1.2 miles short of the runway. The probable cause was loss of engine power due to carburetor icing and the flight instructor's failure to apply carburetor heat.
The real accidents cited above occurred at other airports and in other aircraft — NOT at Tampa Executive Airport. KVDF has its own accident history (see field dominant patterns: loss of control ground 18.4%, hard landing 18.4%, forced landing 15.8%), but these specific events happened elsewhere. The scenario is localized to KVDF 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 C150 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.
Key lesson — In warm, moist Florida 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 wooded wetland or pasture, the decision window is measured in seconds — not minutes. The C150M's marginal climb performance means that any power loss at 350 ft AGL is critical. Early recognition and immediate action are the difference between a clean departure and a forced landing.
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 KVDF. 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. Scan the tachometer as part of your regular instrument scan, especially in conducive conditions.
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. The C150M's marginal climb performance means that any power loss at 350 ft AGL is critical — you have very little altitude to work with.
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's marginal climb performance makes every second count.
The C150M has a best rate of climb (Vy) of only 68 KIAS and a climb rate of roughly 500 fpm at sea level — and that is in ideal conditions. At gross weight, in heat, or with high density altitude, the climb rate is even lower. A partial power loss at 350 ft AGL means you are losing altitude faster than you can regain it. Early application of carburetor heat is not optional; it is the difference between a clean departure and a forced landing. Best glide is 60 KIAS — memorize it and fly it if power is lost.
Off Runway 05 at KVDF, the off-field environment is wooded wetland and pasture — landable but not ideal.
The USGS NLCD ground cover off Runway 05's departure end (heading 042°) is mostly wooded wetland, pasture/hay, and medium development. This is not open water or a paved road, but it is not a smooth field either. A forced landing in wooded wetland requires a shallow descent angle and the slowest possible touchdown speed. Flaps are your friend — full flaps (40°) in the C150M reduce touchdown speed to the minimum, reducing impact energy. Know this before you line up on Runway 05.
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 Florida summer 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 wooded wetland is waiting too long.
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. Localized to Tampa Executive Airport (KVDF).
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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