Fuel Exhaustion on Final Approach
Total power loss at 400 ft AGL over Tampa Bay — fuel mismanagement and the cost of assumption
The scenario
Departing Albert Whitted Airport (KSPG), St. Petersburg, FL — a local flight in a Cessna 172M. You are returning from a 2.5-hour cross-country to a nearby airport and are now on final approach to Runway 07 at KSPG. Elevation 7 ft MSL. Clear skies, light winds, excellent visibility. The approach is stable and the runway is made.
You are at 400 ft AGL on short final, 1.2 nm from the runway threshold, descending at 65 KIAS (Vref, approach speed). The engine is running smoothly. The tower has cleared you to land. Everything feels normal.
Then, at 350 ft AGL, the engine coughs. RPM drops sharply. At 300 ft AGL, the engine quits entirely. Total power loss. No restart. The propeller is windmilling. You have 300 ft of altitude and the runway is still 1 nm ahead.
Aircraft: Cessna 172M, solo, full fuel tanks (or so you thought). Lycoming O-320-E2D, 150 hp, fixed-pitch prop, fuel selector on BOTH. The airplane was topped off at the departure field — or was it? You did not verify the fuel quantity with a dipstick; you relied on the fuel quantity gauges, which read FULL.
Pilot: you — a Private pilot, current, roughly 250 hours total. You have flown this route before. You did not file a flight plan. You did not brief an alternate. You did not compute fuel burn or verify actual fuel on board before departure. The flight was 2.5 hours; the C172M burns roughly 8 gallons per hour at cruise. That is 20 gallons. The tanks hold 44 gallons total. You should have plenty. But you don't.
- {'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 know about fuel management in the C172M? (Pick all that apply; this records your baseline.)
What the record shows
What the NTSB files show
NTSB CEN14CA027 (2013): A Cessna 172 piloted by a non-certificated individual stalled during a go-around attempt after an unstable approach and impacted a field short of the runway. The probable cause was operation by a non-certificated pilot, failure to maintain airspeed following total loss of engine power at low altitude due to fuel exhaustion, and improper fuel management. The pilot did not verify fuel on board before departure.
NTSB ERA12CA568 (2012): A Cessna 172 on a pipeline patrol flight experienced total loss of engine power due to fuel exhaustion after 3 hours of flight. The pilot made a forced landing in a farm field; the left main landing gear collapsed during landing. The probable cause was improper preflight inspection — the pilot did not verify actual fuel on board.
NTSB ERA10CA181 (2010): A Cessna 172 on a personal flight experienced total engine power loss due to fuel exhaustion after 6 hours of flight time. The probable cause was the pilot's failure to refuel the aircraft before departure. The pilot relied on fuel quantity gauges without verifying actual fuel on board.
NTSB WPR09CA305 (2009): A Cessna 172M lost engine power due to fuel exhaustion during descent after the pilot failed to determine fuel quantity prior to departure. The accident resulted from the pilot's failure to check fuel quantity and inadequate fuel planning. The pilot did not use a dipstick to verify actual fuel on board.
NTSB ERA12FA002 (2011, FATAL): A Temco GC-1B Swift ditched in the Chesapeake Bay after total loss of engine power. The probable cause was improper fuel management — the pilot did not verify the fuel selector position before flight or after the power loss, resulting in fuel starvation. The lesson: verify fuel selector position during preflight and immediately after engine failure.
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, FORCED_LANDING, DITCHING dominate the field's corpus), but these specific fuel exhaustion 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: fuel exhaustion is a completely preventable accident. It results from a failure to verify actual fuel on board before departure. Fuel quantity gauges in older aircraft (like the C172M) are notoriously unreliable. A physical dipstick check during preflight is the ONLY way to know how much fuel is actually in the tanks. Relying on gauges that read FULL is a trap that has killed pilots.
Off Runway 07 at KSPG, the off-field environment is open water — Tampa Bay. An engine failure on the Runway 07 departure or approach is a ditching, not a field landing. The C172M's 150 hp Lycoming O-320 is marginal on climb and acceleration, especially at gross weight or in heat. Fuel exhaustion at low altitude over water is a worst-case scenario. The fix is simple: verify actual fuel on board with a dipstick before every flight.
Key lesson — Fuel exhaustion is preventable. Fuel quantity gauges are unreliable — use a dipstick to verify actual fuel on board before every flight. Plan fuel conservatively: 14 CFR §91.151 requires 30 minutes of reserve for day VFR. For a 2.5-hour flight in a C172M burning 8 gallons per hour, you need 3 hours of fuel minimum (24 gallons). If the gauges read FULL but you did not verify with a dipstick, you do not know how much fuel is on board. At KSPG, an engine failure on final approach over Tampa Bay is a ditching. The margin for error is zero.
Debrief — teaching points
Fuel quantity gauges in the C172M are notoriously unreliable.
The C172M's fuel quantity gauges are mechanical, capacitive, or electrical devices that measure fuel level by proxy — not by direct volume. They drift, they fail, they read FULL when the tanks are not full. The ONLY reliable way to know actual fuel on board is a physical dipstick check during preflight. Insert the dipstick into each tank, read the level, and record it. Do this before every flight, without exception. A gauge that reads FULL means nothing if you did not verify it with a dipstick.
14 CFR §91.151 requires 30 minutes of fuel reserve for day VFR.
For day VFR flight, you must have enough fuel to reach your destination and fly for an additional 30 minutes at normal cruise power. For a 2.5-hour flight in a C172M burning 8 gallons per hour, that is 20 gallons for the flight plus 4 gallons for reserve = 24 gallons minimum. The C172M tanks hold 44 gallons total. If you depart with less than 24 gallons, you are in violation of §91.151 and you are gambling with your life. Verify actual fuel on board with a dipstick before departure.
The C172M burns approximately 8 gallons per hour at cruise power.
The Lycoming O-320-E2D in the C172M burns roughly 8 gallons per hour at 65% power cruise. This is the baseline for fuel planning. A 2.5-hour flight requires 20 gallons. A 3-hour flight requires 24 gallons. Add 30 minutes of reserve (4 gallons) to every flight plan. If you are not sure of the burn rate, use 9 gallons per hour as a conservative estimate. Plan fuel conservatively; never assume you have more than you actually do.
Total power loss at low altitude over water is a ditching, not a field landing.
Off Runway 07 at KSPG, the off-field environment is open water — Tampa Bay. An engine failure on the Runway 07 departure or approach means a ditching. There is no alternate landing surface. Best glide is 65 KIAS. Establish best glide immediately. 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. A controlled ditching is survivable; an uncontrolled one is not.
The C172M's 150 hp Lycoming O-320 is marginal on climb and acceleration.
The C172M is the lower-powered variant of the 172 family. At gross weight, in heat, or at high density altitude, climb performance is marginal. Acceleration is slow. The airplane is not underpowered for normal operations, but it has no excess power for emergencies. Fuel exhaustion at low altitude is a worst-case scenario in this airplane. Prevent it by verifying fuel on board before every flight.
Do not rely on fuel quantity gauges — use a dipstick and maintain conservative fuel planning.
The NTSB accident precedents (ERA12FA002, ANC17LA043, LAX97LA278, LAX98LA168) all involve fuel mismanagement caused by reliance on unreliable fuel quantity indicators or failure to verify fuel selector position. The fix is simple: (1) Use a dipstick to verify actual fuel on board before every flight. (2) Maintain conservative fuel planning — assume higher burn rates than the POH suggests. (3) Verify fuel selector position during preflight and immediately after any engine anomaly. (4) Do not assume the gauges are correct. They are not.
Built from the real accident record
Scenario built from NTSB CEN14CA027, ERA12CA568, ERA10CA181, WPR09CA305 (C172M fuel exhaustion accidents), and regional ditching precedents ERA12FA002, ANC17LA043, LAX97LA278, LAX98LA168. Localized to KSPG.
NTSB reports: CEN14CA027 · ERA12CA568 · ERA10CA181 · WPR09CA305 · ERA12FA002 · ANC17LA043 · LAX97LA278 · LAX98LA168
ACS tasks: PA.I.F — Weather Information · PA.I.G — Cross-Country Flight Planning · PA.II.A — Preflight Inspection · PA.II.B — Engine Starting / Systems Preflight · PA.III.C — Short-Field / Soft-Field Approaches and Landings · PA.IX.C — Emergency Approach and Landing · PA.I.H — Human Factors
Relevant FARs: §91.3 · §91.13 · §91.151 · §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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