I develop this document while studying for my EASA ATPL exams. To accomplish this I studied the Oxford Manual and did the Aviation Exam database. The information is brief and easy to read. I believe it contains all the information you will need to pass your exam. I hope you like it and can use it t...
InstrumentATION
ATPL
STUDENT
pilot
resume
all info you need to pass atpl exams
, INSTRUMENTS
Pressure
• Aneroid capsule/pressure diaphragm used for
- Low pressure fuel pump
- Intake pressure of gas turbine engine powerplant
- Manifold pressure gauge
• Bellows sensor used for
- Cabin differential pressure
- Fuel pressure gauge
- Manifold pressure
• Bourdon tube/transducer measures hydraulic pressure
• Manifold pressure is absolute pressure in intake near inlet valve
• 1 BAR = 15 psi = 1000hpa or 100000 PASCAL
Temperature
• SAT = TAT – (Ram rise x Kr)
SAT = RAT ÷ [1+ (0.2 x Kr x M2)]
SAT = TAT ÷ [1+ (0.2 x M2)]
• Ratiometer: Operates without SUPPLY VOLTAGE*
• Bimetallic thermometers
- Based on iron & brass having different coefficients of linear expansion
- - 50°c to 400°C
• Thermocouple
- Temperature increase voltage increase
- Uses thermoelectric effect to measure differential temperature
Fuel measurement
• Electric float: Simple, independence of power supply voltage if made of ratiometer
• Integrating fuel flow with respect to time
• Mechanical fuel flow meter: Spring loaded vane
Tachometer
• Measures angular speed
• Transmitter fitted with magnetic sensor connected to an RPM indicator: Permanent magnet rotating in a non-
magnetic cup, AC converted to square pulses
• Magnetic tachometer: Permanent magnet rotating inside a non-magnetic cup
• Mechanical: Shaft rotates magnet in drag cup
• Electronic: Inductive probe/notched wheel rotating in a magnetic field. Uses magnetic sensor, Disadvantage:
Needs power supply
• Electrical: Uses generator, magnet rotor, principle of measuring rotation speed of a synchronous motor
energized by an alternator
1. DC generator:
- Advantage: Easy transmission, independent of power supply
- Disadvantage: Spurious signals
2. Single phase:
- Advantage: Suppression of spurious signals due to D.C, independent of power supply, simple design, no
influence of temperature
- Disadvantage: Suffers line resistance, transmission problems
3. 3 Phase: Consists of generator, synchronous motor turning drag cup & magnetic tachometer. Frequency
varies with RPM. (Most common)
4. Electrical induction:
- Advantage: Not sensitive to line resistance, independent of power supply, can use several indicators
connected in parallel to a single transmitter
- Disadvantage: Affected by temperature variations
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller ThePilotPT. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $14.09. You're not tied to anything after your purchase.
