Rough Climb Over Central Florida
Carburetor ice in a marginal-climb airplane — partial power loss at 500 ft AGL and a decision that has no good options
The scenario
Departing Lakeland Linder International Airport (KLAL), Lakeland, FL — Runway 10, climbing out on a 090° heading. Elevation 142 ft MSL; the runway is essentially at sea level. KLAL is a towered field (Class D, ceiling 2,600 MSL), open 24 hours.
It is a warm, humid Florida morning in late spring: OAT 26°C, dew point 20°C, altimeter 29.94. Scattered clouds at 3,000 ft, light rain shower one mile to the northeast. Visibility 7 SM. The conditions are classic Gulf Coast — warm, moist, and exactly the environment the FAA icing probability chart marks as 'serious icing at glide power, moderate icing at cruise power.' The relative humidity is 75%.
You are 500 ft AGL, climbing through 68 KIAS (Vy, best rate of climb), heading 090°, when the engine begins to run rough. Power is noticeably down — the tachometer is dropping. The Cessna 150M is a marginal-climb airplane at gross weight; you are solo but full fuel. Off the Runway 10 departure end (heading 090°), the off-field environment is mixed: low-density development, open developed areas (parks/large lots), and dense development farther out. Not ideal, but not water. Behind you, Runway 10's other end (Runway 28) is 8,500 ft away.
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. The 150M has a service ceiling of 12,650 ft, but climb performance at gross weight in warm, humid conditions is marginal — expect 300–400 fpm at sea level, less as altitude increases.
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 the engine sounded fine at first.
- {'label': 'Field', 'value': 'KLAL · Lakeland Linder'}
- {'label': 'Runways', 'value': '5/23 · 10/28'}
- {'label': 'Elevation', 'value': '142 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 and partial power loss on climb? (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 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 initial climb experienced partial engine power loss due to carburetor ice in conditions with 70% relative humidity conducive to serious icing at glide power. The pilot applied carburetor heat but improperly — the improper use of carb heat, combined with operation on Mogas in icing conditions, resulted in the power loss.
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: carb heat is the first response; the forced landing is the second.
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 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 stall at low altitude was fatal.
NTSB CEN23FA077 (2023, FATAL): A Cessna 150H on an instructional flight conducted a night visual approach to a non-towered airport in dark conditions with no cultural lighting. 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 Lakeland Linder International Airport. KLAL has its own accident history (dominant patterns: loss of control in-flight 23.7%, loss of control on ground 19.4%, forced landing 17.2%, hard landing 11.8%, runway excursion 8.6%), but these specific events happened elsewhere. The scenario is localized to KLAL 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.
Key lesson — In warm, humid 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 on the departure, the decision window is measured in seconds — not minutes. Off Runway 10 at KLAL, the off-field environment is mixed terrain: open parks/large lots are your best option, but dense development is nearby. A delayed response means a forced landing in marginal terrain, not a return to the airport.
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 KLAL. 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 26°C OAT with 75% relative humidity, you are in the serious icing zone 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. At 500 ft AGL on climb-out, a 200 RPM drop is a red flag.
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.
At KLAL Runway 10, an engine failure on departure is a forced landing in mixed terrain.
The off-field environment off Runway 10's departure end (heading 090°) is mixed: low-density development, open developed areas (parks/large lots), and dense development farther out. There is no single ideal landing surface. If the engine quits on the Runway 10 departure and altitude is insufficient to return to the airport, your best option is an open park or large lot — aim for the smoothest, most open area you can see. Best glide is 60 KIAS. Flaps for slowest possible touchdown speed — impact energy rises with the square of speed, so the slowest possible speed matters most. Know this before you line up on Runway 10.
The C150M is a marginal-climb airplane — especially at gross weight in warm, humid conditions.
The C150M has a service ceiling of 12,650 ft, but climb performance at gross weight in warm, humid conditions is marginal — expect 300–400 fpm at sea level, less as altitude increases. Density altitude at KLAL on a warm, humid morning can be 500–800 ft higher than field elevation. At 500 ft AGL with a rough engine, you are not climbing — you are barely maintaining altitude. Do not count on climb performance to get you out of trouble. Recognize the marginal-climb limitation and plan accordingly.
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 warm, humid Florida departure with OAT near 26°C and dew point near 20°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 is waiting too long.
Built from the real accident record
Scenario built from NTSB ERA25LA028, ANC25LA005, ERA24LA087 (C150 carburetor ice / partial power loss on climb), WPR21LA329, CEN21LA381, ERA21LA284 (C150 carb ice forced landings), and CEN23FA401, CEN23FA077 (C150 power loss / stall accidents). Real events occurred at other airports — NOT at Lakeland Linder. Localized to KLAL.
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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