Engine Failure on Climb — KSPG Runway 07
Carburetor ice, power loss at 400 ft AGL, and open water ahead — the decision window is seconds
The scenario
Departing Albert Whitted Airport (KSPG), St. Petersburg, FL — Runway 07, climbing out on a 062° heading. Elevation 7 ft MSL; the runway is essentially at sea level. Off Runway 07's departure end: open water — Tampa Bay. There is no alternate landing surface ahead on the initial climb.
It is a warm, 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 air at reduced power is exactly the environment the FAA icing probability chart marks as 'serious icing at glide power, moderate icing at cruise power.'
You are 400 ft AGL, climbing through 78 KIAS (Vy, best rate of climb), heading 062°, when the engine begins to run rough. Power is noticeably down — the tachometer is unwinding. The water of Tampa Bay fills the windscreen ahead. KSPG's tower is part-time (0700–2100) and is open; you are in Class D airspace.
Aircraft: Cessna 172M, solo, full fuel, within limits. Carbureted Lycoming O-320-E2D (150 hp), fixed-pitch prop, steam panel (vacuum-driven attitude and heading), fuel selector on BOTH. Nothing was written up; the airplane was airworthy at departure. The 172M is the lower-powered variant — climb performance is marginal, especially in heat and at gross weight.
Pilot: you — a Private pilot, current, roughly 200 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, focused on airspeed and heading.
- {'label': 'Field', 'value': 'KSPG · Albert Whitted'}
- {'label': 'Runways', 'value': '7/25 · 18/36'}
- {'label': 'Elevation', 'value': '7 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 the C172M and engine failure on climb? (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. Ambient conditions (75°F OAT, 55°F dew point) were conducive to serious carburetor icing per the FAA icing probability chart. The pilot made a forced landing in a field. The probable cause was listed as 'partial loss of engine power for undetermined reasons' — but the conditions and symptom pattern are consistent with carburetor icing.
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 — a fatal mistake at low altitude. The probable cause was the pilot's failure to maintain airspeed, with contributing factors being the loss of engine power due to carburetor icing and high density altitude. The lesson: when power is lost at low altitude, establish best glide (65 KIAS) immediately and do not maneuver to avoid obstacles — the stall is worse than the obstacle.
NTSB CEN22LA309 (2022): A Cessna 172M experienced engine power loss during cruise flight near Friend, Nebraska due to a stuck exhaust valve. The pilot performed a forced landing in a field between corn crops, resulting in substantial fuselage damage. The probable cause was loss of engine power due to a stuck valve — a mechanical failure, not icing.
NTSB WPR13LA035 (2012): A Cessna 172M on an aerial photography mission experienced loss of engine power when the pilot applied full throttle during climb. The accident resulted from failure of the throttle control cable outer jacket, which fragmented and prevented proper throttle control. The pilot made a forced landing. The probable cause was failure of the throttle control cable during maneuvering flight.
NTSB CHI07LA177 (2007): A Cessna 172M departed approximately 243 pounds over gross weight and out of balance. During initial climb at 100–150 ft AGL, the engine lost power; the aircraft stalled and impacted terrain (fatal). The probable cause was the pilot's improper weight and balance and failure to maintain sufficient airspeed to avoid a stall during takeoff-initial climb. Propeller damage indicated significant engine power at impact — the engine was running, but the airplane was stalled.
The real accidents cited above occurred at other airports and in other aircraft — NOT at Albert Whitted Airport. KSPG has its own accident history (LOSS_OF_CONTROL_INFLIGHT 20%, FORCED_LANDING 16.4%, DITCHING 12.7%), but these specific NTSB events happened elsewhere. The scenario is localized to KSPG to make the off-field environment real and consequential for you as a student here.
The consistent thread across all these events: the C172M is a marginal-performance airplane, especially at gross weight and in high density altitude. Engine failures — whether from carburetor icing, mechanical defects, or weight-and-balance problems — happen at low altitude when there is no room for error. The decision window is measured in seconds. The correct response is immediate: apply carb heat if roughness appears, establish best glide (65 KIAS) if power is lost, and do not stall trying to stretch the glide or avoid obstacles. A controlled ditching in open water is survivable; a stall at 400 ft AGL is not.
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 water, the decision window is measured in seconds — not minutes. Off Runway 07 at KSPG, the off-field environment is Tampa Bay: a delayed response means a ditching, not a field landing. Best glide is 65 KIAS; do not stall trying to stretch the glide.
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 KSPG. 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 KSPG Runway 07, an engine failure on departure is a ditching.
The off-field environment off Runway 07's departure end (heading 062°) is open water — Tampa Bay. There is no alternate landing surface. If the engine quits on the Runway 07 departure and altitude is insufficient to return to the airport, the outcome is a ditching. This is not a worst-case scenario; it is the geographic reality. Best glide is 65 KIAS. Doors unlatched before water contact. 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 07.
The C172M is a marginal-performance airplane — especially at gross weight and high density altitude.
The C172M (150 hp) is the lower-powered variant of the 172 family. Climb performance is noticeably reduced compared to the 172N. At gross weight, in heat, or at high density altitude, the climb rate can be marginal. This means there is less altitude cushion for an engine failure on climb. Preflight weight and balance carefully. Do not depart overweight or out of balance. Know your climb performance for the day's conditions.
Proactive carb heat use in conducive conditions is not optional.
The C172M 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°C and dew point near 22°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 400 ft AGL over Tampa Bay is waiting too long.
Built from the real accident record
Scenario built from NTSB ERA09LA379 (2009 C172M carburetor ice / forced landing), DFW05CA237 (2005 C172M carb ice / stall on approach), CEN22LA309 (2022 C172M engine failure / forced landing), WPR13LA035 (2012 C172M throttle cable failure / forced landing), and CHI07LA177 (2007 C172M weight-and-balance / stall on climb). Localized to KSPG with real off-field environment (open water off Runway 07).
NTSB reports: ERA09LA379 · DFW05CA237 · CEN22LA309 · WPR13LA035 · CHI07LA177
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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