What if...?

jpower

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James
I've been compiling a mental list of what ifs for a while now. These are scenarios that you probably didn't discuss in detail during your training. We talk a lot about what happens when you get an engine fire. Duh, shut the fuel off, get down on the ground ASAP. But what about if things start to go just a little south? That's what these are. So I figured I'd let you have at them. Others, feel free to add to the list. What if...

...your fuel pressure reads 1 needle width high on runup? Three needle widths?

...your fuel pressure starts increasing in flight? At what point, if any, do you divert?

...your fuel pressure starts dropping in flight? At what point do you divert?

...your voltmeter is indicating .1 volts low at runup. Take off or turn back? How about .3 volts low? At what point do you turn back or take off? Also, how about if its indicating high voltage?

...your voltmeter indicates .1 volts low in flight. How about .3 volts? When do you land?

...your voltmeter starts reading high in flight. When do you divert, if at all?

...the oil temperature is reading a needle width into the yellow caution zone at runup. Stay on the ground or go flying? Where's your limit?

...the oil temperature creeps up into the yellow caution in flight but then holds steady. Check it out on the ground at your destination? Assume the pressure is steady.

...the oil pressure and temperature both creep into their respective caution zones but hold steady there. Continue to your destination or divert?

Again, feel free to add others...I'm sure I will.
 
Owning my own plane, I know exactly how everything should be.
...your fuel pressure reads 1 needle width high on runup? Three needle widths?

Either one goes to the A&P.

...your fuel pressure starts increasing in flight? At what point, if any, do you divert?

Check boost pump off. If so, immediate divert to find the cause before a filter or fitting blows and a fire starts.


...your fuel pressure starts dropping in flight? At what point do you divert?

Boost pump on, check to make sure the current tank is not on empty. Divert to determine the problem.


...your voltmeter is indicating .1 volts low at runup. Take off or turn back?

Watch it.


How about .3 volts low? Also, how about if its indicating high voltage?

No flying until cause determined.


...your voltmeter indicates .1 volts low in flight. Watch it

How about .3 volts? When do you land? Shed load and land to investigate


...the oil temperature is reading a needle width into the yellow caution zone at runup. Stay on the ground or go flying? Where's your limit?
Back to the hangar. Oil temp is usually not anywhere near normal temps until pattern alt. Anything over normal prior to takeoff results in A&P trip.


...the oil temperature creeps up into the yellow caution in flight but then holds steady. Check it out on the ground at your destination? Assume the pressure is steady.

Assume not in a max climb in hot weather. A&P trip.

...the oil pressure and temperature both creep into their respective caution zones but hold steady there. Continue to your destination or divert?

Divert. Likely a blocked oil passage.
Oil is the only thing your engine has. Anything out of line with oil temp or pressure is a divert.
It costs $15k to overhaul my engine. I can pay for a lot of overnights and rental cars with $15k.


Again, feel free to add others...I'm sure I will.
 
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How about...
You work a W&B calculation and you are 50 pounds over your maximum takeoff weight and it would be a pain in the arse to defuel the airplane.

As for the rest of the questions, most stuff like that has a "Normal" range which is typically marked as a green arc. If it's anywhere in the green arc you're usually good to go. What you'd be looking for then are changes to what is normal for your airplane. What is the trend? What is causing the changes? Judgement and experience into into the equation. Do your homework, a lot of times you can learn a lot with a thorough reading of the POH or the engine operating manuals put out by the manufacturer, you know the stuff that nobody hardly ever reads.
 
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Tell the Missus that she can take any three of the six bags that she has sitting by the door.

How about...
You work a W&B calculation and you are 50 pounds over your maximum takeoff weight and it would be a pain in the arse to defuel the airplane.
 
Tell the Missus that she can take any three of the six bags that she has sitting by the door.
Ah, I see you've flown with my wife...

I learned a lesson. Now I have a set of suitcases that we use. She can only take what fits into hers. Problem solved - more or less.
 
On a hundred degree day with a temperature inversion, it's not uncommon to fly a Rotax with the oil temp a third of the way into the yellow. Shallow out the climb and it will go away after 20 minutes or so. I had no fuel pressure gauge until I installed a Dynon EMS. Not sure having more to worry about makes me a safer pilot.
 
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