Performance & Limitations - C: Aircraft Performance Flashcards
What are some of the main elements of aircraft performance (9)?
a. Takeoff and landing distance.
b. Rate of climb.
c. Ceiling.
d. Payload.
e. Range.
f. Speed.
g. Fuel economy.
h. Maneuverability.
i. Stability.
(FAA-H-8083-25)
What factors affect the performance of an aircraft during takeoffs and landings?
a. Air density (density altitude).
b. Surface wind.
c. Runway surface.
d. Upslope or downslope of runway.
e. Weight.
(FAA-H-8083-25)
What effect does wind have on aircraft performance?
Takeoff—The effect of a headwind is to allow the aircraft to reach the lift-off speed at a lower ground speed, which will increase airplane performance by shortening the takeoff distance and increasing the angle of climb. The effect of a tailwind is the aircraft needs to achieve greater ground speed to get to lift-off speed. This decreases aircraft performance by increasing takeoff distance and reducing the angle of climb.
Landing—The effect of wind on landing distance is identical to its effect on takeoff distance. A headwind will lower ground speed and increase airplane performance by steepening the approach angle and reducing the landing distance. A tailwind will increase ground speed and decrease performance, by decreasing the approach angle and increasing the landing distance.
Cruise flight—Winds aloft have somewhat an opposite effect on airplane performance. A headwind will decrease performance by reducing ground speed, which in turn increases the fuel requirement for the flight. A tailwind will increase performance by increasing the ground speed, which in turn reduces the fuel requirement for the flight.
How does weight affect takeoff and landing performance?
Increased gross weight can have a significant effect on takeoff performance:
a. Higher liftoff speed;
b. Greater mass to accelerate (slow acceleration);
c. Increased retarding force (drag and ground friction)
d. Longer takeoff distance.
The effect of gross weight on landing distance is that the airplane will require a greater speed to support the airplane at the landing angle of attack and lift coefficient resulting in an increased landing distance.
What effect does an increase in density altitude have on takeoff and landing performance?
An increase in density altitude results in:
a. Increased takeoff distance (greater takeoff TAS required).
b. Reduced rate of climb (decreased thrust and reduced acceleration)
c. Increased true airspeed on approach and landing (same IAS).
d. Increased landing roll distance.
Define the term density altitude.
Density altitude is pressure altitude corrected for nonstandard temperature.
The density of the air has a direct effect on:
a. Lift produced by the wings
b. Power output of the engine
c. Propeller efficiency
d. Drag forces
What factors affect air density?
Altitude—the higher the altitude, the less dense the air.
Temperature—the warmer the air, the less dense it is.
Humidity—more humid air is less dense.
(FAA-P-8740-2)
How does temperature, altitude, and humidity affect density altitude?
a. Density altitude will increase (low air density) when one or more of the following occurs:
• High air temperature
• High altitude
• High humidity
b. Density altitude will decrease (high air density) when one or more of the following occurs:
• Low air temperature
• Low altitude
• Low humidity
(FAA-P-8740-2)
Know the following speeds for your airplane!
V S0 —Stall speed in landing configuration - 49
V S1 —Stall speed clean or in specified configuration - 55
V Y —Best rate-of-climb speed - 76
V X —Best angle-of-climb speed - 64
V FE —Maximum flap extension speed - 102
V A —Maneuvering speed - 113 (normal), 89 (utility)
V NO —Normal operating speed - 125
V NE —Never exceed speed - 154
VG - Best Glide Speed - 76
Vapp - approach speed - 66 @ 40 Deg
Explain the difference between best glide speed and minimum sink speed.
Best glide speed—is the speed and configuration that provides the greatest forward distance for a given loss of altitude. In most airplanes, best glide airspeed will be roughly halfway between V X (best angle of climb speed) and V Y (best rate of climb speed).
Minimum sink speed—is used to maximize the time that the airplane remains in flight. Use of minimum sink speed results in the airplane losing altitude at the lowest rate. It is important that pilots realize that flight at the minimum sink airspeed results in less distance traveled and is useful in flight situations where time in flight is more important than distance flown (i.e. more time to fix problem, ditching at sea). Minimum sink speed is not an often published airspeed but generally is a few knots less than best glide speed.
How many miles can you glide in your aircraft per 1,000 feet of altitude lost?
About 1.5 mi per 1,000 ft. altitude. About 9 to 1 at 6,000ft (10 miles) Check POH glide range chart in performance for exact numbers. Ratio is 8.1 to 10.5 to one at 2,550lbs, VG and no wind.
What information can you obtain from the following performance charts?
- Takeoff
- Fuel-Time Dist to climb
- Cruise/range
- Crosswind
- Landing Charts
- Stall speed perf chart
Takeoff charts—These allow you to compute the takeoff distance of the airplane with no flaps or with a specific flap configuration. You can also compute distances for a no flap takeoff over a 50-foot obstacle scenario as well as with flaps over a 50-foot obstacle. The takeoff distance chart provides for various airplane weights, altitudes, temperatures, winds, and obstacle heights.
Fuel, time, and distance-to-climb chart—This chart will give the fuel amount used during the climb, the time it will take to accomplish the climb, and the ground distance that will be covered during the climb. To use this chart, obtain the information for the departing airport and for the cruise altitude.
Cruise and range performance chart—This is designed to give true airspeed, fuel consumption, endurance in hours, and range in miles at specific cruise configurations.
Crosswind and headwind component chart—This allows for figuring the headwind and crosswind component for any given wind direction and velocity.
Landing charts—Provide normal landing distance as well as landing distance over a 50-foot obstacle.
Stall speed performance charts—These are designed to give an understanding of the speed at which the airplane will stall in a given configuration. Will typically take into account the angle of bank, the position of the gear and flaps, and the throttle position.
Define the term pressure altitude, and state why it is important.
Pressure altitude—the altitude indicated when the altimeter setting window (barometric scale) is adjusted to 29.92. This is the altitude above the standard datum plane, a theoretical plane where air pressure (corrected to 15°C) equals 29.92 in. Hg. Pressure altitude is used to compute density altitude, true altitude, true airspeed, and other performance data.
The following questions are designed to provide pilots with a general review of the basic information they should know about their specific airplane before taking a flight check or review.
- What is the normal climb-out speed? - 76
- What is the best rate-of-climb speed? - 76
- What is the best angle-of-climb speed? - 64
- What is the maximum flap extension speed? - 102
- What is the stall speed in the normal landing configuration? - VSo - 49
- What is the stall speed in the clean configuration? - VS1 - 55
- What is the normal approach-to-land speed? - 66 @40deg flaps
- What is maneuvering speed? - Va - 113
- What is red-line speed? - VNe - 125
- What engine-out glide speed will give you maximum range? - 76
- What is the make and horsepower of the engine? - Lycoming O-360-A4m, O: Opposed, 361ci, Direct Drive, 8.5:1 compression, 180 HP
- What are the minimum and maximum oil capacities? - 5.5 tp 7.5 qts
- What weight of oil is being used? - Aeroshell 100 Ashless SAE 50
- What are the nosewheel turning limitations for your aircraft? - 30 foot Min turn Radius - pivot point to wingtip
- What is the maximum allowable/demonstrated crosswind component for the aircraft? - 16 knots
- How many people will this aircraft carry safely with a full fuel load? - 4 ppl with no baggage
- What is the max allowable weight the aircraft can carry with baggage in the baggage compartment? 2,550 lbs
- What takeoff distance is required if a takeoff were made from a sea-level pressure altitude? - 1,800 feet, no wind @ max weight
- What is your maximum allowable useful load? - 1,031.75 lbs (AC W&B Sheet)
