Cessna 172S Steam Performance & Weight and Balance — PPL Oral Exam Questions

DPE oral questions · performance & weight and balance

13 questions a DPE may ask in this section

1. Question 1 · PA.I.F.K1

   How does density altitude affect aircraft performance?

   What a DPE expects to hear

   • High density altitude = reduced performance
   • Longer takeoff roll
   • Reduced rate of climb
   • Higher true airspeed for same IAS
   • Reduced engine power output (naturally aspirated)
   • Density altitude increases with: high pressure altitude, high temperature, high humidity

   SourcePHAK FAA-H-8083-25C Chapter 11; AFH FAA-H-8083-3C

2. Question 2 · PA.I.F.K1

   What is the purpose of weight and balance calculations?

   What a DPE expects to hear

   • Ensure aircraft is within maximum gross weight limits
   • Ensure center of gravity (CG) is within approved limits (forward and aft limits)
   • Aircraft outside CG limits may be uncontrollable
   • Aft CG: reduced longitudinal stability, can be unrecoverable in stall
   • Forward CG: increased stability but may not have sufficient elevator authority for flare

   SourcePHAK FAA-H-8083-25C Chapter 10

3. Question 3 · PA.I.F.K2

   What effect does a headwind have on takeoff performance? A tailwind?

   What a DPE expects to hear

   • Headwind decreases takeoff roll (aircraft reaches Vr at a shorter ground distance)
   • A 10-knot headwind component reduces takeoff roll significantly
   • Tailwind increases takeoff roll — the rule of thumb is a 10-knot tailwind increases takeoff distance by approximately 21%
   • Crosswind component matters too — maximum demonstrated crosswind component is in the POH

   SourceAFH FAA-H-8083-3C; POH performance charts

4. Question 4 · PA.I.F

   Passengers decide to switch seats just before start. Does this matter if total weight is the same?

   What a DPE expects to hear

   • YES — moving weight changes CG
   • Passenger to back seat moves CG aft = less stable, harder to recover from stall

   SourcePHAK Chapter 10; ACS Task I.F

5. Question 5 · PA.I.F

   We have a 50-foot obstacle at the end of this 2,500-foot runway. Walk me through your configuration and procedure.

   What a DPE expects to hear

   • Set flaps to manufacturer recommended setting (e.g., 10° C172, 25° Warrior)
   • Full power before brake release
   • Rotate at calculated speed, climb at Vx until obstacle cleared
   • Then accelerate to Vy and slowly retract flaps

   SourceACS Task IV.E; POH Section 4

6. Question 6 · PA.I.F

   Wind is 20 knots at 30° to the runway. Is this landing legal and how will you adjust flap setting?

   What a DPE expects to hear

   • No regulatory crosswind limit for private pilots — must adhere to POH maximum demonstrated crosswind and personal minimums
   • Strong crosswind = smaller flap setting recommended for better directional control

   SourceACS Task IV.B; POH Section 4/5

7. Question 7 · PA.I.F

   What are your criteria for a stabilized approach and at what altitude must these be met?

   What a DPE expects to hear

   • Final landing configuration, correct flight path, target airspeed (+10/-5 knots), steady rate of descent
   • For VFR: stabilized by 500 feet AGL

   SourceACS PA.IV.B.S6; AFH Chapter 9

8. Question 8 · PA.I.F

   It's 95°F at an airport with 5,000-foot elevation. How does this affect our ground roll vs. standard day at sea level?

   What a DPE expects to hear

   • High density altitude = significantly longer takeoff roll
   • Less engine power, less propeller thrust, wings require higher true airspeed to generate lift
   • Must reach much faster groundspeed before rotation

   SourceAviation Weather Handbook Chapter 8; PHAK Chapter 11

9. Question 9 · PA.I.F

   We're flying at max gross weight. How does this extra weight change our takeoff and climb performance?

   What a DPE expects to hear

   • Higher liftoff speed = longer ground roll
   • Extra mass reduces rate of climb
   • Increases stall speed in all configurations

   SourceACS Task I.F; PHAK Chapter 11

10. Question 10 · PA.I.F

    Wind is 15 gusting to 25. Why might we choose Flaps 10° or 20° instead of full flaps?

    What a DPE expects to hear

    • Partial flaps allow higher approach speed — greater safety margin above stall during sudden wind lulls
    • Also reduces wing area acted on by crosswind, making rollout easier to handle

    SourceACS Task IV.B; POH Section 4

11. Question 11 · PA.I.F

    On a short-field landing, how do you get the most stopping power without blowing the tires?

    What a DPE expects to hear

    • After touchdown: retract flaps AND apply maximum braking while holding control wheel FULL BACK
    • Flap retraction and back pressure transfer weight from wings to main wheels, increasing tire-pavement friction

    SourcePOH Section 4; ACS Task IV.F

12. Question 12 · PA.I.F

    We're landing at an airport with density altitude of 8,000 feet. Will our approach speed on the indicator be higher, lower, or the same as at sea level?

    What a DPE expects to hear

    • Indicated airspeed will be THE SAME as sea level
    • However true airspeed and groundspeed will be significantly higher — results in longer landing roll

    SourceAviation Weather Handbook Chapter 8; PHAK Chapter 11

13. Question 13 · PA.I.F

    During takeoff roll, what engine or flight instrument indications would cause you to immediately abort?

    What a DPE expects to hear

    • Sluggish acceleration, rough engine operation, static RPM below POH range, zero or negative airspeed indication halfway down runway

    SourcePOH Section 4; ACS Task IV.A