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AGK question ! want some help!

  • davidyeung1991
  • Topic Author

davidyeung1991 created the topic: AGK question ! want some help!

Q1. if centre zero ammeter show the needle is point to exactly 0 what does it means??

Q2. when notice the carburettor ice during descend , and you will be landing, and your aircraft have carburettor term gauge,
1.apply fully carburettor for descend
2.apply partial carburettor for descend
3.apply fully carburettor for descend, reduce partial for landing

Q3.
during flight u noting left magneto failure, what happen ?
1. RPM reduce in fix pitch aircraft
2.RPM reduce, with CSU aircraft

Q4. during the flight you noting the fuel flow gauge is high
1.the fuel line is leak
2.something block the fuel line
3.....
4.....
#1

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bobtait replied the topic: AGK question ! want some help!

I can only give you answers based on the information you have given.

Q1 A zero reading on the centre-zero ammeter would indicate that the system voltage is equal to the battery voltage [equal 'pressure' at both ends so no current flow to or from the battery]. This could be caused by the alternator being unable to cope with the demands of the system because too many loads are turned on. That causes the alternator voltage to drop to equal the battery's voltage. The other possibility is that the alternator is faulty and is unable to attain its rated voltage which should be a little higher than the battery.

Q2 A magneto failure causes the engine to lose power. That will result in an RPM drop for a fixed pitch propeller aircraft.

Q3 If an aircraft is fitted with a carburettor air temperature gauge, is is usual to apply partial carburettor heat to get the temperature out of the likely icing range. Not many aircraft have CAT gauges nowadays.

Q4 Many GA aircraft have a fuel flow gauge that actually measures fuel pressure and displays the result as an equivalent fuel flow. That works fine as long as the fuel lines and injectors are clean and clear of any blockage. A blockage in a fuel line in such an aircraft will result in an increase in fuel pressure [that's like partly blocking the outlet to a hose with your thumb to increase the pressure]. The instrument will then give a false reading showing high fuel flow when the actual fuel flow as actually decreased.
#2

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bobtait replied the topic: AGK question ! want some help!

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  • aviatrix

aviatrix replied the topic: AGK question ! want some help!

Hey everybody,

Need clarification on this one;

When establishing a climb after takeoff , the proper sequence of engine control adjustment with a CSU is
A)mixture followed by RPM and MP
B)MP and mixture but not RPM
C)MP followed by RPM then mixture
D)RPM, mixture then MP

Kind regards
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bobtait replied the topic: AGK question ! want some help!

The correct answer is (c).
Assuming the climb has been done with take-off power (in GA aircraft that usually means full throttle and pitch fully fine), the idea is to avoid a configuration where the manifold pressure is very high but the RPM is low. That causes a problem called 'over boosting' which can lead to detonation and engine damage.

Since at take-off power, both manifold pressure and RPM will be as high as they are ever going to be, when reducing power from take-off power to climb power, it is good practice to reduce the manifold pressure first followed by the reduction in RPM. This ensures that the combination of high manifold pressure and low RPM will be avoided.

Then, if the engine manufacturer recommends leaning at climb power, the mixture is leaned last of all. This technique is much more appropriate when you are operating a high power turbo charged engine.
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  • Weetabix is life

Weetabix is life replied the topic: FUEL FLOW GUAGE

An unusually high fuel flow guage reading is the result of a

A. clogged fuel pump ( I chose)
B.broken fuel lines
C. failure of engine driven pump

What's your answer sir


Another question is

During prolong descent with a set RPM &MP , what would the pilot be cautious about?

A. Overcooling
B. overheating
C. Propeller tip speed
D. Maintaining set RPM & MP


Need your help sir!

Kind regards.
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bobtait replied the topic: FUEL FLOW GUAGE

An unusually high fuel flow guage reading is the result of a

A. clogged fuel pump ( I chose)
B.broken fuel lines
C. failure of engine driven pump

None of these answers make any sense to me. Many fuel flow gauges actually measure fuel pressure and then indicate an equivalent flow. In those cases, any restriction in the fuel injection lines or nozzles can give a false reading because fuel pressure will rise and so a high fuel flow will be indicated.

During prolong descent with a set RPM &MP , what would the pilot be cautious about?

A. Overcooling
B. overheating
C. Propeller tip speed
D. Maintaining set RPM & MP

A long descent with very low power applied can cause rapid cooling of an air cooled piston engine. This is called 'thermal shock' and it can damage cylinders and valves.
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