“I think the left engine is leaking oil”

“I think the left engine is leaking oil,” said my Private AMEL add on client yesterday on the way to his checkride (and my ATP checkride). I glanced at the left nacelle and saw dark runny liquid flowing from the top vent, with little ripples here and there. Not good. A glance at the oil pressure gauge showed all was good there. There was an airport just 14 miles in front of us. I told Center “Not an emergency, but it looks like a small oil leak. We’re landing at KXYZ.” Center asked about fuel and souls on board. I answered but reiterated “not an emergency.” “Let me know when you’re ready to copy a number…” I copied the number and reported I was changing to CTAF/1200. I handled the radio while my client flew, though I maintained supervision. I pointed out it will still be a normal landing as long as he quit flying the Seminole well over 100 knots! Descent and landing were uneventful. We taxied onto the ramp and shut down to investigate. My client is a big guy; he played football for Clemson. He commented several times in training about how tight the dipsticks could be on preflight. He wanted to be sure \*he\* didn’t put his weight into it and crank down too hard. You can see where this is going. The dipstick on the left engine was completely unscrewed. The right engine was not far behind. We determined we had lost about a half quart, so added a quart. Washed our hands and flew on to the checkride. Oh. Did I tell you we found the airplane on the ramp first thing w/ a flat tire? Yup. The day didn’t get off to a great start. Army friends talk about “threes.” 1. Flat tire. 2. Oil issue. 3. Brutally hot. Hmm. The superstitious would probably cancel. My client did great on his checkride, but after just one hour he and the DPE were soaked in sweat. I wasn’t in the mood to hand fly an ATP checkride in the Seminole (no autopilot) in that heat. The DPE was really not interested in a two-hour flight in the same heat. And, weather was deteriorating. We pulled the plug. Leaving to fly home we dodged the weather that was right where my checkride couldn’t have taken place. We bounced along at 6,500 because going higher didn’t make sense. So, I was glad not to have spent two plus hours under the hood at 2000 feet! My client learned a lot yesterday – in-flight-not-quite-emergency, ADM considerations (weather and significant cost associated with rescheduling my checkride), prioritizing “aviate/navigate” over “communicate,” and to tighten the dipsticks a little better. Oh, I called Center once I knew what the issue was. The guy said they didn’t treat it as an emergency, but he wanted to know everyone was OK. I can live with that. I had an engine failure in an Arrow years ago and told my wife that in a twin I could just shut an engine down if no oil pressure and land on one instead of totaling the airplane in a pine forest clearing. I considered whether or not to secure the engine. I was confident we were going to be OK for a few more minutes and we continued under reduced power. One interesting take away – I was really intrigued at how runny the oil was as it flowed out. I’m used to the viscosity of room temperature oil. This was flowing right out of the crankcase and reduced viscosity was obvious! (At a FAASTeam event a couple months ago the presenter suggested putting some oil in a paper cup and placing it in the refrigerator to see how thick it is in the winter. I can only imagine \*that\* extreme!) (I’m doing ATP because I want to. No pressing job need for it. So I don’t mind waiting.) One of the questions on the ATP Written last week was a compare/contrast between a precautionary landing and an emergency landing. How prescient.