Presentation on theme: "Ex. 8 - Descending. What you will learn: How to descend at a variety of airspeeds and power settings to a desired altitude How to accurately level off."— Presentation transcript:
Ex. 8 - Descending
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. OBJECTIV E
Ex. 8 - Descending 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. MOTIVATI ON Why?
Ex. 8 - Descending 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 LINKS down.
Ex. 8 - Descending Lets see how much you already know: Q What mixture setting should be used for descents? Q What should be carb heat position in a descent? Q What effect does reducing power have on yaw? Q How does one control yaw after reducing power? BACKGROUND KNOWLEDGE - TKT Why?
Ex. 8 - Descending x Power-off Descents (Gliding) ATTITUDE + POWER = PERFORMANCE What aspects of performance? airspeed (how fast were going) rate of descent (how fast were going DOWN) HOW FAR WE CAN GLIDE Distance x x x Important assumption: NO WIND When might gliding be useful? THEORIES & DEFINITIONS Where do we find the magical optimal number? Where do we find the distance we can glide at that airspeed? Gliding at different speeds too fasttoo slowjust right
Ex. 8 - Descending Gliding: Estimating Range THEORIES & DEFINITIONS What can the pilot do to stretch the glide? Will the pilot make that spot? ZERO WIND
Ex. 8 - Descending Gliding: Estimating Range THEORIES & DEFINITIONS 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 Power-on Descents THEORIES & DEFINITIONS 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 Now you change rate of descent and airspeed independently How much power?
Ex. 8 - Descending Power-on Descent Types THEORIES & DEFINITIONS Landing Approach stabilized descent at specific airspeed to touchdown at specific point Enroute no hurry to lose altitude more comfortable for passengers Power setting Carb heat Airspeed Flaps Usually below green arc (about rpm) Above green arc ( rpm below cruise power) HOT COLD See POH (55-65 knots in Cessna 150) Close to cruise speed Down (for better forward visibility and lower safe descent speeds) Up (enroute descent done at high speed, low rate of descent – no need for additional lift and drag)
Ex. 8 - Descending Procedures Downwind Check Power-off Descent Entry During Approach Descent Entry During Enroute Descent Entry During Recovery from Descents Leveling out Overshoot. PROCEDURES
Ex. 8 - Descending Downwind Check Oil Temperature and Pressure in the green Primer in and locked, Master ON, Mags on BOTH Circuit Breakers in, Ammeter Needle right, Overvoltage Light OFF Carb Heat hot, Mixture rich Fuel ON, gauges show sufficient fuel Flaps UP Brake pressure. PROCEDURES
Ex. 8 - Descending Power-off Descent: Entry PROCEDURES P ower A ttitude T rim You have it down PAT Cockpit check: oil T+P in the green, carb heat hot, mixture rich Look-out! maintain cruise attitude until airspeed reaches best glide set descent attitude for that airspeed smoothly reduce power to idle How will power reduction affect yaw? retrim airplane
Ex. 8 - Descending Power-off Descent: During PROCEDURES 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 Approach Descent: Entry PROCEDURES P ower A ttitude T rim Cockpit check: oil T+P in the green, carb heat hot, mixture rich Look-out! maintain cruise attitude until airspeed enters white arc once airspeed is in white, extend flaps set descent attitude for approach airspeed (see POH) smoothly reduce power to rpm retrim airplane
Ex. 8 - Descending Approach Descent: During PROCEDURES 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 Enroute Descent: Entry PROCEDURES P ower A ttitude T rim Cockpit check: oil T+P in the green, mixture rich Look-out! establish descent attitude at near cruise airspeed smoothly reduce power to rpm from cruise retrim airplane
Ex. 8 - Descending Enroute Descent: During PROCEDURES 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 Leveling Out PROCEDURES Power Attitude Trim Continue look-out! return airplane to cruise attitude smoothly add power to approximately cruise setting carb heat cold How will adding power affect yaw? retrim airplane Begin leveling out at 10% of rate of descent If climbing up to 3500 feet at 300 feet per minute, begin leveling out at…
Ex. 8 - Descending Overshoot! PROCEDURES P ower A ttitude T rim flaps up to 20 o set up a climb at 55 knots wait for +ve rate of climb on VSI flaps up in stages full power carb heat cold retrim airplane. Why retract some flap right away? Why not retract all flap at once?
Ex. 8 - Descending Considerations Effect of Flaps Effect of Wind. CONSIDERATIONS
Ex. 8 - Descending Effect of Flaps on Descent CONSIDERATIONS 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 Effect of Wind CONSIDERATIONS 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) x x x x NO WINDHEADWINDTAILWIND
Ex. 8 - Descending 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 Review: Q What is your airplanes best glide speed? Q During an approach to landing your intended touchdown spot is drifting up. What does that mean and how do you fix the situation? Q Same as above, but the spot is drifting down. REVIEW What is its significance?
Ex. 8 - Descending 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. CONCLUSION