Thanks for all the contributions!
'Balls to the wall, crossfeed on, boost pumps on'
That's an easy one to remember! I like it.
Switching tanks can be tricky, because there will be a delay before the engine restarts, which has caused some people to switch back to the original (empty) tank, after which the bit of fuel from the non-empty tank comes through, "confirming" your belief that you are on the right tank now
Good point. Waiting 2 mins on a tank would probably feel like forever so I can quite believe some pilots might not stick to that. It also makes me wonder about flight attitude. If you have unusable fuel presumably there are attitudes where you can still pick up the last bit of usable fuel?
So 500 man, I Hope that answers your question.
Thanks for that BPF.
Looking at potential engine related problems, I've scraped together the following list which are all problems listed in various POHs and the Lycoming engine operations manual. These are all things which a pilot can get some indication of in flight and possibly do something about. It's not a complete list by any means so feel free to add to it, but if we are thinking about a check list for engine related issues we should consider what problems can occur and what indications there may be. The fixes are only suggestions so don't take them as absolute gospel!
Idle roughness - Sometimes accompanied by a loss of power which can lead to stoppage in slow flight. Caused by an excessively rich idle fuel flow.
Fix - Leaning the mixture may improve roughness or be required to restart.
Engine driven fuel pump failure - Sudden reduction in fuel flow immediately followed by a total loss of power.
Fix - Switch on the boost pump.
Insufficient fuel - Oops!
Fix - Change tanks if you can!
Excessive fuel vapour - On injected engines may cause fuel flow variations and power surges which may lead to power loss. More likely to occur while taxiing.
Fix - Boost pump on, adjust mixture for smooth operation and if the problem continues try changing tanks.
Contamination - Most likely water which may cause fluctuating RPM, power loss or even stoppage. Other than noticing it I don't think there is much that can be done about it in flight.
Fix - Better preflight?
Lycoming:
Experience indicates that draining should be accomplished before refuelling, because fuel servicing mixes the water and fuel, and the water may not have settled to the bottom of the tank until the airplane is airborne.
Spark plug fouling - Caused by carbon or lead deposits forming mainly due to excessively rich mixtures. Identified by an obvious power loss running on an individual magneto.
Fix - Appropriate leaning should resolve this in flight.
Magneto malfunction - Sudden engine roughness or misfiring.
Fix - Select each magneto individually to identify the culprit and select the good magneto only. Different power or mixture settings may enable continued operation on both magnetos.
Intake ice/ carburettor ice - impact or refrigeration ice leading to rough running, power loss or stoppage.
Fix - With an injected engine use alternate air to bypass the blockage and carburettor heat on a carburetted engine (30s - 2min).
Q. If you had intake icing and had switched to alternate air, at what point would you consider switching back? Or would you at all?
Broken or deformed baffles/ seals/ cowl flaps - Reduction in cooling air around the engine. Higher than normal CHT or oil temperature. Possibly leading to pre-ignition (over heating spark plug barrels).
Fix - Reduce temperature by either en-richening the mixture, reducing power, or opening cowl flaps, or a combination of all three.
Oil loss - High oil temperature accompanied by low pressure likely means a failure is imminent. Likewise high oil pressure caused by a blocked breather tube may lead to a crankshaft nose seal rupturing and a spectacular loss of oil.
Fix - None
Interesting side note about preventing freezing in breather tubes which extend into the airflow (from Lycoming):
It is normal practice for the airframe manufacturer to provide some means of preventing freeze-up of the crankcase breather tube. The breather tube may be insulated, it may be designed so the end is located in a hot area, it may be equipped with an electric heater, or it may incorporate a hole, notch or slot which is often called a “whistle slot.”
Detonation - May be caused by leaning at high power settings and is unlikely to be noticeable unless severe.
Pre-ignition - Usually indicated by roughness, backfiring and a sudden increase in CHT.
Fix - (from Lycoming Engine Operations Manual)
The best temporary in-flight methods for correcting preignition and detonation are to reduce the cylinder temperature by retarding the throttle, enriching the mixture, opening cowl flaps if avail*able, or a combination of all of these.
That's all I've got time for, but one last note of interest from Lycoming:
Interpreting Your Engine Instruments
The present-day piston engine instruments used in the typical general aviation airplane are not precision laboratory instru*ments. We exclude the turbine and jet-powered aircraft from this discussion and will consider only piston engines, recognizing that the more expensive pressurized twin-engine models may also be exceptions. If one was to observe an irregular reading of one engine instrument, it calls for a cross-check on all other instruments, and not relying on one instrument as a basis for a decision affecting flight.