Ex. 8 - Descending

1. Ex. 8 - Descending Ex. 8 - Descending

2. OBJECTIVE What you will learn: • How to descend at a variety of airspeeds and power settings to a desired altitude • How to accurately level off at desired altitude and establish cruise • How to descend to a specified touch-down point. Ex. 8 - Descending

3. MOTIVATION Why learn this? • As with climbs, different situations call for different types of descents • Even more variables to consider than for climb (power can be varied) • Accurate descents are even more important than accurate climbs. Why? Ex. 8 - Descending

4. LINKS Links You already have understanding of: • attitudes and movements • power control • mixture and carburetor heat control And you learned how make the plane go up… And what goes up, must come down. Ex. 8 - Descending

5. BACKGROUND KNOWLEDGE - TKT Let’s see how much you already know: Why? • What mixture setting should be used for descents? • What should be carb heat position in a descent? • What effect does reducing power have on yaw? • How does one control yaw after reducing power? Why? Ex. 8 - Descending

6. THEORIES & DEFINITIONS Theories and Definitions • Power-off Descents (Gliding) • Gliding: Estimating Range • Power-on Descents • Power-on Descent Types Ex. 8 - Descending

7. THEORIES & DEFINITIONS What aspects of performance? When might gliding be useful? Power-off Descents (Gliding) ATTITUDE + POWER = PERFORMANCE • airspeed(how fast we’re going) • rate of descent(how fast we’re going DOWN) Where do we find the magical optimal number? Gliding at different speeds Where do we find the distance we can glide at that airspeed? x HOW FAR WE CAN GLIDE Important assumption: NO WIND x x x Distance too slow too fast just right Ex. 8 - Descending

8. THEORIES & DEFINITIONS Gliding: Estimating Range ZERO WIND Will the pilot make that spot? What can the pilot do to stretch the glide? Ex. 8 - Descending

9. THEORIES & DEFINITIONS Gliding: Estimating Range NOTHING! Plane is already flying at best gliding speed! Raising the nose will: • shorten your gliding distance • AND • make your airspeed to dangerously low NEVER TRY TO “STRETCH” A GLIDE. Ex. 8 - Descending

10. THEORIES & DEFINITIONS How much power? Now you change rate of descent and airspeed independently Power-on Descents • Normal descents are power-assisted • Power = more choice for performance • +/- 100 rpm = +/- 100 feet per minute or • +/- 100 rpm = +/- 5 knots. With power off, each airspeed corresponded to a set rate of descent Ex. 8 - Descending

11. THEORIES & DEFINITIONS Power-on Descent Types Usually below green arc (about 1500-1900 rpm) Above green arc (100-300 rpm below cruise power) HOT COLD See POH (55-65 knots in Cessna 150) Close to cruise speed Up (enroute descent done at high speed, low rate of descent – no need for additional lift and drag) Down (for better forward visibility and lower safe descent speeds) Ex. 8 - Descending

12. PROCEDURES Procedures • “Downwind” Check • Power-off Descent • Entry • During • Approach Descent • Entry • During • Enroute Descent • Entry • During • Recovery from Descents • Leveling out • Overshoot. Ex. 8 - Descending

13. PROCEDURES “Downwind” Check • Oil Temperature and Pressure in the green • Primer in and locked, Master ON, Mags on BOTH • Circuit Breakers in, AmmeterNeedle right, Overvoltage Light OFF • Carb Heat hot, Mixture rich • Fuel ON, gauges show sufficient fuel • Flaps UP • Brake pressure. Ex. 8 - Descending

14. PROCEDURES How will power reduction affect yaw? Power-off Descent: Entry Cockpit check: oil T+P in the green, carb heat hot, mixture rich Look-out! Power Attitude Trim • smoothly reduce power to idle • maintain cruise attitude until airspeed reaches best glide • set descent attitude for that airspeed You have it down PAT • retrim airplane Ex. 8 - Descending

15. PROCEDURES Power-off Descent: During • Keep good look-out • Maintain coordinated flight with rudder • Maintain straight flight with ailerons • Every 500 feet smoothly add full power, then reduce back to idle Why? Ex. 8 - Descending

16. PROCEDURES Approach Descent: Entry Cockpit check: oil T+P in the green, carb heat hot, mixture rich Look-out! Power Attitude Trim • smoothly reduce power to 1500-1900 rpm • maintain cruise attitude until airspeed enters white arc • once airspeed is “in white”, extend flaps • set descent attitude for approach airspeed (see POH) • retrim airplane Ex. 8 - Descending

17. PROCEDURES Approach Descent: During • Keep good look-out • Maintain coordinated flight with rudder • Maintain straight flight with ailerons • Control attitude and airspeed with pitch • Control descent rate with power. Ex. 8 - Descending

18. PROCEDURES Enroute Descent: Entry Cockpit check: oil T+P in the green, mixture rich Look-out! Power Attitude Trim • smoothly reduce power to 100-300 rpm from cruise • establish descent attitude at near cruise airspeed • retrim airplane Ex. 8 - Descending

19. PROCEDURES Enroute Descent: During • Keep good look-out • Maintain coordinated flight with rudder • Maintain straight flight with ailerons • Control attitude and airspeed with pitch • Control descent rate with power. Ex. 8 - Descending

20. PROCEDURES If climbing up to 3500 feet at 300 feet per minute, begin leveling out at… Leveling Out Begin leveling out at 10% of rate of descent Continue look-out! Power Attitude Trim • smoothly add power to approximately cruise setting • carb heat cold How will adding power affect yaw? • return airplane to cruise attitude • retrim airplane Ex. 8 - Descending

21. PROCEDURES Overshoot! • full power • carb heat cold Power Attitude Trim Why retract some flap right away? • flaps up to 20o • set up a climb at 55 knots • wait for +’ve rate of climb on VSI • flaps up in stages Why not retract all flap at once? • retrim airplane. Ex. 8 - Descending

22. CONSIDERATIONS Considerations • Effect of Flaps • Effect of Wind. Ex. 8 - Descending

23. CONSIDERATIONS Effect of Flaps on Descent • More lift • can safely descend at lower airspeeds • More drag • steeper descent given same airspeed • More nose-down attitude • better forward visibility given same airspeed Airspeed must be in white arc before flaps are extended! Ex. 8 - Descending

24. CONSIDERATIONS Effect of Wind • In headwind: can glide further by increasing airspeed slightly (offset effect of wind pushing you back) • In tailwind: can glide further by decreasing airspeed slightly (take advantage of lower rate of descent at slightly lower airspeed) NO WIND TAILWIND HEADWIND x x x x Ex. 8 - Descending

25. SAFETY SAFETY • Cockpit check before all descents • Carb heat: on for any descent at rpm below green arc • Engine warm-up: every 500 feet during glides • Glides: never try to “stretch” • Flaps: airspeed must be “in the white” • Constant look-out! (for other traffic and obstacles.) Ex. 8 - Descending

26. REVIEW Review: What is its significance? • What is your airplane’s best glide speed? • During an approach to landing your intended touchdown spot is drifting up. What does that mean and how do you fix the situation? • Same as above, but the spot is drifting down. Ex. 8 - Descending

27. CONCLUSION Conclusion: • As you can see, even seemingly simple procedures involve a lot of details and considerations. But all the different procedures and considerations are related, and we keep coming back to the basic principles from earlier lessons. • Today you learned about one of the most fundamental and important flying skills. After practicing this lesson, you will be well on your way towards learning to land! • Read for next lesson: Ex. 9 – Turns. Ex. 8 - Descending