Introduction
You’re flying a Cessna 150L Commuter on a VFR flight direct from Perry-Foley Airport (KFPY) on the west coast of Florida, to St. Augustine Airport (KSGJ) on the east coast. The flight should take a little over an hour. About 40 minutes into the flight, you’re over the town of Lake Butler at 5500 feet. You look around the cockpit and then play the “what if” game with your iPad.
Watch the video and try to see what’s wrong.
What’s wrong?
- You’re about to experience an emergency. Land now—even off airport.
- An emergency is imminent. Land at the nearest airport, a private strip called Flying Tiger Field.
- You might have a problem, but you have time. Land at the nearest airport with services, which is Lake City Gateway (KLCQ).
- There’s probably nothing wrong. Continue towards St. Augustine for now.
Watch the Scenario
Watch the Explanation
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Explanation:
The answer is 3: You might have a problem, but you have time. Land at the nearest airport with services, which is Lake City Gateway (KLCQ).
The Oil Pressure gauge is indicating “0.” However, the Oil Temperature is normal—and not rising.
According to the POH, “If low oil pressure is accompanied by normal oil temperature, there is a possibility the oil pressure gauge or relief valve is malfunctioning. A leak in the line to the gauge is not necessarily cause for an immediate precautionary landing because an orifice in this line will prevent a sudden loss of oil from the engine sump. However, a landing at the nearest airport would be advisable to inspect the source of trouble.”
In this case, the nearest airport with services is Lake City Gateway (KLCQ), 16 miles to the northwest.
If a total loss of oil pressure is accompanied by a rise in oil temperature, the POH advises that “there is good reason to suspect an engine failure is imminent.” In that case, you should reduce engine power and land immediately at a suitable forced landing field if there’s no airport nearby.
With no indicated oil pressure but normal oil temperature, you’re probably safe to follow the POH’s guidance and head for the nearest airport with services. That’s Lake City Gateway. Along the way, you should keep your eye out for rising Oil Temperature—and keep suitable landing sites within gliding range.
This airplane uses a mechanical oil pressure gauge, so it’s unlikely the zero reading is simply a failure of the sensing system or gauge. With an electric pressure gauge, this situation is even more likely to be a non-event that turns out to be simply a failed sensor. However, even that should be treated as an abnormal situation where you land as soon as practicable.
In addition, 14 CFR 91.7 (b) states, “The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.” Because the oil pressure gauge is required equipment, the aircraft is technically unairworthy. The regulation does leave some room by not defining “discontinue the flight,” but continuing for a long distance and bypassing multiple landing opportunities is probably not what they had in mind.
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With that short view of the oil temp, it is hard to tell if the oil temp is steady or rising?
Fair, but it could be rising too slowly to see without repeated checking over much longer than you’d want to watch in a video when you don’t even know what’s wrong yet. 😉 So you’d keep watching as you diverted—and change your plan if you saw it was going up too quickly to stay the course.
No CHT gauge on a 150L? Another gauge to watch if you had one.
Could you find a better place for the “Please Comment” sticky widget? It blocks text in the article and I have to either move around to see the missing text or kill all of the sticky stuff in the article.
There’s really no need to ask for comment; it’ll come…
Bottom left of 4 square gauges on right side of panel is bottomed out. If thats oil pressure, I would arranging a rental car.
With oil pressure that high, engine life is measured in seconds…
Personally I’m going to land at Tiger Field as it is much closer, take a look under the cowl, check the oil level, confirm more or less normal temperatures and then call Lake City to make sure there really is a mechanic there. I’d rather make the decision to fly the extra 10 miles when I’m on the ground and have some additional info.
Some of you must be seeing a different video or maybe on your phone, I’m on a PC. The answer is #2, land at Flying Tiger Field. Oil pressure is zero, the engine is about to go quiet. 6.1 nm is 37,064 ft. from the airport, 5,500 ft. altitude x 8 glide ratio for a C-150 = 44,000 ft glide range, more than enough to make the field with no power.
What we all see is an oil pressure gauge reading zero. The question remains: Is the actual oil pressure in the engine case zero, or is this a bad gauge or blocked passage near the gauge? The normal oil temp hints this is just an instrument error. But even if it is not, the engine will continue to run with zero oil pressure for quite some time. There’s nothing wrong with #2 from a strictly safety perspective, but even the POH agrees that a precautionary landing where it can be checked out is just fine.