Rough Climb Out of Tampa International
Carburetor ice in a marginal off-field environment — the 172M's low power and dense development make this a close call
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.
It is a humid Florida afternoon in late spring: OAT 28°C, dew point 22°C, altimeter 29.92. Scattered clouds at 2,500 ft, light rain shower two miles to the northeast. Visibility 8 SM. Classic Gulf Coast conditions — warm, moist, and exactly the environment the FAA icing probability chart marks as 'serious icing at glide power, moderate icing at cruise power.' Density altitude is approximately 2,800 ft.
You are 500 ft AGL, climbing through 78 KIAS (Vy), heading 092°, when the engine begins to run rough. Power is noticeably down — the tachometer is dropping. The off-field environment ahead is dense development interspersed with open developed areas (parks, large lots) and wooded wetland — marginal forced-landing terrain. KTPA tower is active 24/7 and is aware of your departure. You are in Class B airspace.
Aircraft: Cessna 172M, solo, full fuel, within limits. Carbureted Lycoming O-320-E2D, 150 hp, fixed-pitch prop, steam panel, fuel selector on BOTH. Nothing was written up; the airplane was airworthy at departure. The 172M's 150 hp is marginal in warm, high-density-altitude conditions — climb performance is already reduced.
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 heads-down on the climb and focused on 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': 'C172M'}
- {'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 C172M? (Pick all that apply; this records your baseline.)
What the record shows
What the NTSB files show
NTSB ERA09LA379 (2009): A Cessna 172M student pilot on a solo instructional flight experienced engine power loss during the base-to-final turn in the traffic pattern and made a forced landing in a field. The accident resulted from carburetor icing at glide power, with ambient conditions (75°F OAT, 55°F dew point) conducive to serious icing per the FAA icing probability chart. The pilot did not apply carburetor heat until after the power loss was evident.
NTSB DFW05CA237 (2005): A Cessna 172M lost engine power during initial climb due to carburetor icing and made a forced landing in a field. The pilot stalled while maneuvering to avoid a fence. Contributing factors included high density altitude (the C172M's 150 hp is marginal in heat) and the pilot's failure to maintain airspeed during the forced landing. The engine power loss was attributed to carburetor icing in serious icing conditions.
NTSB CEN24LA168 (2024): A Cessna 172M on an IFR flight to Bemidji Regional Airport experienced engine power loss due to carburetor icing during descent in night IMC. The pilot touched down on a building roof and impacted a retaining wall and ground. The accident was attributed to delayed use of carburetor heat, which resulted in ice accumulation beyond the point where heat could restore full engine power.
NTSB CEN22LA181 (2022): A Cessna 172M on a personal flight experienced partial engine power loss during a go-around attempt from a low approach to an upsloping turf runway. The accident resulted from the pilot's failure to use carburetor heat during the approach and an unsuitable flight profile for the runway configuration. The partial loss of engine power was attributed to carburetor icing.
The real accidents cited above occurred at other airports and in other aircraft types — NOT at Tampa International Airport. KTPA has its own accident history (see field dominant patterns: forced landing 22.2%, loss of control inflight 11.1%), but these specific carburetor-ice 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 C172M 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. The C172M's 150 hp makes climb performance marginal in high-density-altitude conditions; a partial power loss is more consequential in this airplane than in a 172N.
Key lesson — In warm, moist Gulf Coast air, the C172M's carbureted O-320-E2D 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. Off Runway 10 at KTPA, the off-field environment is marginal (dense development, parks, wooded wetland): a delayed response means a forced landing in difficult terrain, not a comfortable field 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 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 C172M's Lycoming O-320-E2D is carbureted; it has no 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 C172M, 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.
At KTPA Runway 10, an engine failure on departure is a forced landing in marginal terrain.
The off-field environment off Runway 10's departure end (heading 092°) is dense development interspersed with parks, open lots, and wooded wetland — marginal forced-landing terrain. There is no open field, no clear area. If the engine quits on the Runway 10 departure and altitude is insufficient to return to the airport, the outcome is a forced landing in difficult terrain. This is not a worst-case scenario; it is the geographic reality. Best glide is 65 KIAS. Doors unlatched before landing. Master off just before impact. 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 10.
The C172M's 150 hp makes climb performance marginal in high-density-altitude conditions.
The C172M is the lower-powered variant of the 172 family (150 hp vs. the 172N's 180 hp). In warm, high-density-altitude conditions like those at KTPA on a summer afternoon, climb performance is already reduced. A partial power loss from carburetor ice is more consequential in this airplane than in a higher-powered variant. Density altitude at KTPA on this scenario day is approximately 2,800 ft — the airplane climbs as if it were at 2,800 ft elevation, not 26 ft. Proactive carburetor heat use is not optional.
Built from the real accident record
Scenario built from NTSB ERA09LA379 (2009 C172M carburetor ice / forced landing), DFW05CA237 (2005 C172M carb ice / stall on descent), CEN24LA168 (2024 C172M delayed carb heat / power loss), and CEN22LA181 (2022 C172M carb ice / go-around failure). Anonymized and localized to KTPA.
NTSB reports: ERA09LA379 · DFW05CA237 · CEN24LA168 · CEN22LA181
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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