June 10, 1991 – Discovering that Oil Pressure is just as important as you would think!
Every year the Florida HRS* would do a low level survey of nuclear power plants in the state. My flying club regularly got the contract, because our mechanic and club co-owner Lenny Francis always sold our services dirt cheap. I was looking to build hours and had a lot of free time so Lenny drafted me.
Two guys from the HRS showed up to fly down to Ft. Pierce (FPR) with me. I don’t remember their exact names but I think Bob was going to ride in the plane with me and Don was going to drive a Suburban that was already parked at the Airport Tiki (the FBO).
I completed my preflight, verifying the engine had 6 quarts of very clean oil. It had just come out of 100 hour inspection, which included a complete oil change with new filter. (OK sorry about the foreshadowing)
Don got in the Suburban and Bob got in the back of the 172 right behind me, so we could both look out the left side.
The Mission
Every year the HRS was surveying 16 “quadrants” extending from a 10 mile radius from each of our three nuclear power plants. Our assignment was the two in central FL, St Lucie and Crystal River. We were supposed to find the closest to the plant of these three categories:
- Habitable Dwelling (obvious)
- Greens producing garden (radiation?)
- Milk producing animal (same)
In my mind, we were finding out where to check in case there was a leak like Three Mile Island, or even worse, like Chernobyl.
The flights we did were pretty exciting. Low altitude, low speed, flaps up so Bob could see, and it was a warm summer day. Many times I was struggling to stay awake flying at 400 feet AGL, 60 knots and no flaps. I wouldn’t want to do it again. Still I’m getting ahead of myself. This is about the flight TO the survey site.
By the way they don’t do this anymore. Any aerial survey is now done using drones.
Maybe It’s The Gauge
After a quick stop in the FBO to “take care of things”, Don jumped in the Suburban with his two way aviation radio. I kept radio 2 tuned to that frequency so I could hear what they were saying, but Bob was behind me with two headsets crisscrossing his head so he could hear me and hear (and speak to) Don. Note: My walkaround was abbreviated because we had just flown for 90 minutes and the engine was obviously still very warm. I did not check the oil, thinking it was not necessary. I do now!
Bob and I took off on Runway 14 and started heading to the southeast.
I intended to climb up to 2500 feet for the approximately 15 mile leg to the survey site. Passing thru 2200 feet I noticed in my scan that the oil pressure gauge was at zero. All the way down.
“Bob, maybe it’s the gauge but right now I’m showing zero oil pressure. As a precaution I’d like to return to the airport OK?”
“John you’re the pilot. You make the call.” I said “We’re returning, tell Don to return to base.”
“Fort Pierce tower, Cessna 75885 is 8 miles southeast, returning to the airport, showing zero oil pressure. It may be the gauge but I’d like a straight in approach to 32 if you don’t mind.”
“Cessna 75885 roger that, winds are very light shouldn’t affect anything. Say souls and fuels on board” and so on. We were cleared to land on runway 32.
I intentionally stayed up above the glide path “just in case”. We landed with the engine at idle and turned off at taxiway Delta, just as the engine stopped with the prop straight up and down. Note: It stopped normally and did not “seize”.
Simultaneously, Bob and I looked at each other and said “It’s not the gauge!”
Don was on his way back to the airport and I got on the phone to Lenny. Answering machine (no voice mail in 1991). I called Jim Grady. He said sit tight and flew down in his vintage C-210C (N3672Y) to pick us up. It was an uneventful ride home. Jim even asked me to take left seat. He told me several times I made the right choice returning to base. Well obviously.
Epilogue
We had used up all the daylight for that day, but the next day Lenny assigned me to N739SK, which I felt was a much more reliable airframe. Over the next two weeks we completed this survey and the survey of the plant near Crystal River using trusty 9SK.
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So What Happened?
Lenny was training a new “mechanics helper” and the young gentleman had done most of the oil change exactly right except for one thing: He put the oil filter gasket in upside down, which is not hard to do. It’s not easy to tell which side is up.
All the way down to Ft. Pierce, the oil filter had been slowly unscrewing itself, and gradually leaking oil. Lenny told me it probably wouldn’t have mattered if I check the oil again anyway as it no doubt started off slowly then sped up at the end. “You probably would have seen 5 quarts. You didn’t see any oil dripping from the plane did you?” Of course I hadn’t! That would have been an immediate red flag. He said that most all of the oil probably leaked out on my second take off, at max throttle, because the filter was by then very loosely attached. (It never did come completely off.) We also got very lucky that the engine had minimal damage and was returned to service only a week later.
I still check the oil before EVERY flight now.
* Florida HRS refers to the former Department of Health and Rehabilitative Services, which was split into two separate departments in 1996: the Florida Department of Children and Families (DCF) and the Florida Department of Health.