21. Performance Flashcards
As air density (increases / decreases) with altitude, both engine and aerodynamic performance also (increase / decrease) with altitude.
decreases; decrease.
A normally-aspirated engine (loses / is able to maintain) its performance as the aircraft climbs.
loses.
As an aircraft climbs at constant IAS, its TAS increases. Therefore, the power required to maintain that IAS (also increases / remains the same).
increases.
Pressure altitude is the altitude in the ISA that has (the same pressure as / a lower pressure than) the actual altitude.
the same.
If the QNH is higher than 1013 hPa, the pressure altitude will be (higher / lower) than the altitude indicated with QNH set on the subscale.
lower.
If the QNH is 1010 hPa, the pressure altitude will be 90 ft (higher / lower) than the QNH altitude.
higher.
Pressure altitude is the altitude indicated when 1013 hPa is set on the altimeter subscale (true / false).
true.
Density altitude is pressure altitude corrected for any difference in temperature from ISA conditions (true / false).
true.
The correction to pressure altitude for every 1-degree celsius deviation from ISA is (30 ft / 120 ft).
120 ft.
Aerodrome elevation is 2,000 ft and the surface shade temperature is (ISA -4 / ISA).
ISA.
The surface shade temperature at sea level is 20-degrees celsius, i.e. ISA +5. For practical purposes you (may / may not) assume the temperature at 6,000 ft will also be ISA +5.
may.
The aerodrome elevation is 1,000 ft, with QNH 1006 hPa and surface temperature is 18-degrees celsius. Calculate pressure altitude and density altitude.
(a) difference between QNH and 1013 = 1013 - 1006 = 7 hPa; convert to feet 7 x 30 = 210; add/subtract from aerodrome elevation 1,000 + 210 = 1,210 ft (added in this case as QNH lower than 1013)
(b) ISA temperature at aerodrome elevation = 15-degrees celsius - (1 x 2degrees) = 13 degrees celsius therefore actual temperature varies from ISA by 18 - 13-degrees celsius = +5=degrees celsius density altitude = pressure altitude 1,210 + (5 x 120) ft = 1,810 ft.
Take-off distance required (TODR) is defined as the distance required to (become airborne / become airborne and climb to 50 ft above the runway surface).
become airborne and climb to 50 ft above the runway surface.
Increased weight (increases / decreases) TODR (Take-off distance required)
increases.
You fly to a high-elevation aerodrome on a hot day and the area QNH is much lower than normal. You should expect both landing and take-off performance to be (much worse / not much changer) by comparison with the performance on a standard day at a lower-level aerodrome.
much worse.
