Engine Failure Over Sarasota Bay
Carburetor ice, partial power loss, and a critical off-field decision — the runway choice matters
The scenario
Departing Sarasota Bradenton International Airport (KSRQ), Sarasota, FL — Runway 04, climbing out on a 038° heading over the Sarasota area on a warm, humid Gulf Coast afternoon. Field elevation 30 ft MSL. The runway is essentially at sea level.
It is late spring, 1400 local: OAT 29°C, dew point 23°C, altimeter 29.91. 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.' The Sarasota Class C airspace is active; tower is open (0600–0000 local).
You are 500 ft AGL, climbing through 73 KIAS (Vy), heading 038°, when the engine begins to run rough. Power is noticeably down — the tachometer is dropping. The off-field environment off Runway 04 is marginal: medium development, wooded wetland, low-density development. Not ideal, but workable. However, Runway 22 is the reciprocal (218° heading) — and off Runway 22's departure end is open water and low-density development: a ditching scenario.
Aircraft: Cessna 172N, solo, full fuel, within limits. Carbureted Lycoming O-320, fixed-pitch prop, steam panel, fuel selector on BOTH. Nothing was written up; the airplane was airworthy at departure. 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.
Pilot: you — a Private pilot, current, roughly 200 hours total. You are familiar with KSRQ; you have trained here. You understand the field layout and the Class C airspace. You are on a local flight, no flight plan, VFR. The tower is aware of your departure.
- {'label': 'Field', 'value': 'KSRQ · Sarasota Bradenton'}
- {'label': 'Runways', 'value': '4/22 · 14/32'}
- {'label': 'Elevation', 'value': '30 ft'}
- {'label': 'Aircraft', 'value': 'C172N'}
- {'label': 'Dominant phase', 'value': 'Takeoff / Landing'}
The decision
Before we get into the decision tree — what do you already know about carburetor ice in the C172N and forced-landing site selection? (Pick all that apply; this records your baseline.)
What the record shows
What the NTSB files show
NTSB CEN24LA362 (2024): A Cessna 172N encountered light rain and carburetor ice at 1,800 ft AGL. 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 CEN14LA276 (2014): A Cessna 172N on a cross-country flight experienced engine roughness and power loss at cruise altitude in conditions conducive to carb icing. The pilot made a forced landing on an island; the aircraft nosed over in soft sand. The pilot survived. The probable cause could not be determined due to premature aircraft release — but the conditions and symptoms are consistent with carburetor ice.
NTSB ANC26LA001 (2025): A Cessna 172 on an instructional flight experienced progressive engine power loss during training maneuvers despite carburetor heat application. The pilot made a forced landing on a road; the aircraft struck a rock during landing roll and nosed over. Atmospheric conditions indicated serious icing conditions in pressure-type carburetors — the O-320 is a pressure-type carburetor.
NTSB WPR15LA086 (2015): A Cessna 172N on an instructional flight over Molokai, Hawaii experienced partial loss of engine power during a climb over mountainous terrain and made a forced landing into densely forested terrain. The reason for the partial loss of engine power could not be determined because the aircraft was not recovered from the remote accident site.
NTSB CEN14LA374 (2014): A Cessna 172N on a personal local flight experienced partial engine power loss during cruise due to failure of the dual magneto system caused by loose mounting screws. Improper maintenance during the annual inspection was a contributing factor.
The local environment at KSRQ makes runway choice critical: Runway 04's departure end (heading 038°) is marginal terrain — medium development, wooded wetland, low-density development. Runway 22's departure end (heading 218°) is open water and low-density development — a ditching scenario. An engine failure on the Runway 04 departure is survivable in the marginal terrain; an engine failure on the Runway 22 departure is a ditching. This is not hypothetical; it is the USGS NLCD ground cover off those runway ends.
The real accidents cited above occurred at other airports and in other aircraft — NOT at Sarasota Bradenton International Airport. KSRQ has its own accident history (dominant patterns: loss of control on the ground 19.2%, forced landing 15.4%, runway excursion 11.5%, hard landing 11.5%, loss of control in flight 11.5%), but these specific NTSB events happened elsewhere. The scenario is localized to KSRQ 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 C172N 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 Gulf Coast air, the C172N'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 near KSRQ, the runway choice matters: Runway 04 departure is over marginal terrain (survivable forced landing); Runway 22 departure is over open water (ditching). The decision window is measured in seconds — not minutes. Know the off-field environment before you line up.
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 KSRQ. You do not need visible ice, freezing temperatures, or IMC. Warm, moist air at reduced power is the classic carb-ice environment. The C172N's Lycoming O-320 is a pressure-type carburetor; it is particularly susceptible. Carburetor heat is the only tool.
The first symptom is subtle — a dropping tachometer and engine roughness.
In a fixed-pitch airplane like the C172N, 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 KSRQ, runway choice in an engine failure matters.
Runway 04's departure end (heading 038°) is marginal terrain: medium development, wooded wetland, low-density development — a forced landing there is survivable. Runway 22's departure end (heading 218°) is open water and low-density development — a forced landing there is a ditching. If you lose the engine on the Runway 04 departure, you have a marginal but workable landing site. If you lose it on the Runway 22 departure, you are in the water. This is not hypothetical; it is the ground cover. Know the off-field environment before you depart.
Best glide is 65 KIAS — establish it immediately and maintain it.
The C172N's best glide speed is 65 KIAS at gross weight. This speed maximizes glide distance and gives the most time and distance to manage the emergency. At 500 ft AGL with a failing engine, establishing 65 KIAS immediately maximizes your options — whether that means reaching the airport or setting up the best possible forced landing. Do not try to stretch the glide by slowing below best glide; you will lose distance and control authority.
Proactive carb heat use in conducive conditions is not optional.
The C172N 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 28–30°C and dew point near 22–23°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 CEN24LA362 (2024 C172N carburetor ice / power loss), CEN14LA276 (2014 C172N engine roughness / forced landing), ERA09LA517 (2009 C172N total power loss), ANC26LA001 (2025 C172N progressive power loss / carburetor ice), WPR15LA086 (2015 C172N partial power loss / mountainous terrain), CEN14LA374 (2014 C172N magneto failure), WPR14LA099B (2014 fuel contamination / forced landing), and WPR12LA306 (2012 C172N exhaust valve failure). Anonymized and localized to KSRQ.
NTSB reports: CEN24LA362 · CEN14LA276 · ERA09LA517 · ANC26LA001 · WPR15LA086 · CEN14LA374 · WPR14LA099B · WPR12LA306
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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