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Pressure pickup locations for EPR

Aviation Mechanic Powerplant (AMP) practice question 12 of 13 on Turbine Engines. ACS element AM.III.B.K3 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONEngine pressure ratio on a turbofan engine is instrumented by total pressure pickups at which two locations?

  1. AThe compressor inlet and the combustion section
  2. BThe fan discharge and the exhaust nozzle throat
  3. CThe engine inlet and the turbine exhaust
Show the answer and explanation

Correct answer: C. The engine inlet and the turbine exhaust

  • A — incorrect No total pressure pickup for EPR is placed in the combustion section; the downstream pickup is in the turbine exhaust.
  • B — incorrect The upstream pickup is at the engine inlet ahead of the fan, not at the fan discharge, and the downstream pickup is in the turbine exhaust.
  • C — correct EPR uses total pressure pickups in the engine inlet, designated Pt2, and in the turbine exhaust, designated Pt7.

BACKGROUND

Engine pressure ratio, or EPR, is an indication of the thrust being developed by a turbofan engine and is used to set power for takeoff on many types of aircraft. It is instrumented by total pressure pickups in the engine inlet, designated Pt2, and in the turbine exhaust, designated Pt7, and the reading is displayed on the flight deck EPR gauge. Takeoff thrust is checked by adjusting the throttle to obtain a single predicted reading on that gauge. Because EPR is a ratio of two pressures, a leak or a cracked probe in either line produces a reading error. Turboprop engines do not use EPR as a power indication; they use a torquemeter instead.

STUDY TIP

Remember the pair as inlet over exhaust, Pt2 over Pt7, and that the number sequence runs front to back through the engine. If you see a question about a turboprop, expect torque rather than EPR.

KEY POINTS

  • EPR indicates turbofan thrust and is used to set takeoff power.
  • The total pressure pickups are in the engine inlet (Pt2) and the turbine exhaust (Pt7).
  • Leaks or damaged probes in either pressure line cause EPR reading errors.

SOURCES

  • FAA-H-8083-32B ch10 "Engine Pressure Ratio Indicator"
Practice the Aviation Mechanic Powerplant (AMP) test →Timed 100-question exam, by ACS area, or review your misses. Free.
MORE ON TURBINE ENGINES

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-32B Aviation Maintenance Technician Handbook – Powerplant, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.