Chances are that most of them spent their careers flying point to point with very little working of the airplane. If they'd spent much time flying large radials, they'd have engine failure experiences to discuss. More than a few. If they put airplanes in demanding environments, they'd have some interesting airplane stories to tell...hours of their own accord mean very little. I've met pilots who have gone much of their career without seeing a hiccup, and I've met others who have been there and own a vault full of tee shirts. Some of the equipment I've flown has had some of the best maintenance that could be had...airplanes are still mechanical objects and still subject to breakage. Put the airplane in an environment which is prone to breaking it, and it only equates to a LOT more maintenance required.
As far as a new place to work...lots of different places, lots of different types of aircraft, and certainly lots of different types of operations. Some are not your father's operation.
Just prior to that forced landing last year, another pilot flying for that operation also made a forced landing. In his case, he ran a tank dry and was unable to retart the engine. In a nutshell, he was an idiot. I saw him do other bone headed things, and in such cases, despite him having considerably more time in type than me, he invited problems upon himself by actually causing the problems. In the case I described above, the problem occured due to a very rare failure of the rear turbine bearing seal, allowing all my oil to exit the airplane; the engine ran like a top, but with no control over the propeller, and while it was producing power, I couldn't use it. Discussions with federal investigators and mx reps after the fact suggested that the engine may be capable of running for another half hour minus the oil, or nearly all the oil, before it gets to that condition, but should show low on the oil pressure. In my case, that didn't happen, and during the actual run to the target, I was in a canyon into the sun on a 3,000' descent in smoke, and primarily focused not on things in the cockpit, but on the rock walls around me.
I believe, based on the information I have now, from discussions with experts in that engine and with those who participated in the incident investigation, that it's very possible the problem might have been discovered sooner...such as when I started the run, which would have given me 3,000 of altitude or more to make a decision, rather than 150-300'. However, I had no indications, nor reason to suspect the problem...and when I spoke to an individual who's an expert in the engine type directly after getting on the ground, he had no clue what could have happened...let alone me trying to analyze it while operating under the conditions I did. Quite frankly, I was confused by what I was seeing in the cockpit; it made no sense, and I had a big neon billboard flashing in the front of my mind asking "what are you doing wrong, and how can you fix it?" It was answered by an equally large billboard that was one big question mark.
The only choice available, and the only prudent one to make, was to set it up as a forced landing and carry it through to completion. Because the way in which it unfolded made no sense to me, I had to believe that I was doing something wrong. There was no time for a checklist, no time for anything but jettisoning the load, making the turn, and reducing to the best glide speed prior to impact and to enable me to clear powerlines. The inner voice was yelling that this was all wrong, that because the scenario didn't match anything that made sense, I must have a good airplane and was about to put a good airplane in the dirt over nothing. I forced myself to push that voice aside; it wanted a theoretical discussion that I didn't have time for, and I made a wheel landing on the terrain straight ahead.
Again, for that reason, I submit that trying to analyze the problem when more immediate demands of flying the airplane exist, can lead to serious complications. In the origional post, I believe the engine roughness occured during a hold; this is a good time to make the decision and if appropriate, get rid of that engine and simplify...but only if the particular needs and the condition of the engine at the time dictate. If it's producing some power and you do need it, and you can tolerate the potential for it to go belly-up and complicate your life during a critical phase of flight (approach and landing), then you might consider keeping it. If the oil pressure is extremely low, the damage is probably already done, or about to be done. Take what you can get.
Conversely, engines do sieze, and some engines do need that oil pressure to feather, and you don't want a runaway propeller, either. A rapid siezure at high torque can cause an engine mount to fail, and some engines with excess heat and wear can cause other problems. Many engine cases are magnesium or mag alloys, as can be generator drives and accessory cases and drives...run these dry and create heat and you can also create a class D metal fire out there, and you definitely don't want that. Further, if you're pumping oil onto a hot engine (low oil pressure...is it going somewhere?) you're setting yourself up for a fire you won't be able to control by merely shutting down the engine.
Coming out of Lake City, FL one morning, I noted the #1 engine could only achieve barometric manifold pressure. I noted the #4 engine was covered in oil as was the wing...which meant the accessory section was full of oil, as well as the exhaust short stacks, which put out flame. I discovered this as we climbed on top of a layer. I didn't want to shut down both engines. The #1 was most likely a failed supercharger clutch, which could cause problems, but appeared functional for now. The #4 engine presented a definite fire hazard, and was losing oil at an undetermined rate, almost certainly through a cracked propeller governor stephead base...not unheard of in that installation. I elected to shut down #4, and monitor #1.
During the enroute portion to St. Joseph, MO, I went below and built up a new stephead motor and governor assembly, and prepared the necessary tools and gaskets. When we arrived, I repaired the #4 assembly, and cleaned the engine. I inspected #1. We performed ground runs, noted the lack of boost and only barometric on #1, and made a reduced power takeoff on all four, with a precautionary shutdown on #1 after takeoff for the remainder of the trip. As it turned out, after some very frustrating troubleshooting the next day, we had a cracked manifold pressure line; the engine was fine, but indicating low.
Evaluate what you have on it's own merits and make a decision; it may be different each time, as the circumstances will almost invariably be different.
After departure in a turbopropeller airplane, I experienced a power loss, albeit slight, on the left engine. I was flying with the company assistant chief pilot. We heard a slight muffled hooting sound, noted that the temps were higher on that engine with less torque. We were empty and repositioning and elected to continue the climb while we considered what we had. So far, nothing overly upsetting; a slight split in the engine gauges. The assist CP went aft and looked outside, came back and said he could hear the noise a little better...a hooting sound. Ahhh, compressor stall, but why? Lots of altitude, in the clear, now we had time to consider our problem. No applicable checklists yet. We levelled into cruise, and I went aft to see. I noted a splined object protruding through the bottom of the cowl. I opened an illustrated parts catalog and found the part; the only splined part in that nacelle assembly was part of an anti-ice door. With that information, and the part number I contacted the Director of Maintenance, and we discussed the situation. We elected to continue to a maintenance base downrange, where it could be inspected and repaired. On arrival, we found exactly what it appeared to be. A new design part from the manufacturer, an all-steel part that had replaced a carbon fibre part with steel inserts, had failed in two places, and had shifted to partially block the induction passage. The splined end I saw was part of the failed door assembly. When I knew what I had, I elected to fly with reduced power on that engine, and the moaning compressor sound went away. No more engine asthma...a common fix during a compressor stall involving mechanical damage. In this case, no engine damage, just a partial nacelle occlusion.
I knew based on the research I'd done, the engine wasn't going to ingest that door. Absolute worse case, we could evntually intentionally perform a precautionary shutdown, but we elected to operate it at reduced power, which solved the problem and actually extended our range. Had I been flying an approach, I wouldn't have thought twice about it, but would have reduced power based on the audible responses in the cockpit, and failing that as a fix, shut it down. If I'd seen something else entirely, such as low oil pressure or excessive heat, I'd have shut it down right away.
) I'd evaluate it just like any other engine problem...how badly do I need the engine, and what would be the safety consequences if I tried to keep it running when it REALLY didn't want to. A properly conducted engine shutdown with subsequent approach and landing really a non-event in my experience.
