On Landings Part I FAA P-8740-48.


Published on

On Landings Part I FAA P-8740-48. This pamphlet includes a complimentary video: https://www.youtube.com/watch?v=5ThKEI8ibwM&list=PL1EvWLSzQrXO71Dm-QN_9repsMo7k1Zeg

Published in: Education, Technology, Business
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

On Landings Part I FAA P-8740-48.

  1. 1. FAA–P–8740–48 • AFS–8 (2008)HQ-08562On Landings Part IFederal AviationAdministration
  2. 2. On Landings Part IIntroductionBeing a safe pilot means combining your working knowledge of aviation with current skills and experience—tempered by good judgment.One important phase of flying skill is the landing. Landing phase accidents are responsible for nearly half ofall general aviation accidents. By fortifying your knowledge of the “whys” and “wherefores” of approach andlanding accidents, you can become a safer pilot.In this pamphlet, we will look at undershooting and cross-control stalls—the kinds of accidents that can happenbefore you reach the runway. Also, we will look at hard landings, porpoising, and loss of directional control—problems encountered after reaching the runway.The UndershootAt one time or another every one of us has miscalculated an approach and started to undershoot the runway. It’shard to forget that “sinking” feeling you had when you first realized that the airplane might not make the runway.Poor pattern techniques, suchas flying too wide a pattern ondownwind or making a late turnto base leg, are frequent causes ofundershooting.
  3. 3. On Landings Part IAnother cause is failure to maintainadequate power on final.Some pilots succumb to “runwayfixation” and unconsciously try to“carry” the airplane up to the landingspot by easing the nose up withoutadding power. This technique doesn’twork very well.You can help set up a proper andconstant distance from the runwayfor all airports by placing the runwaycenterline at a specific point on theleading edge of the wing (low wingairplane) or a point along the strut(high wing airplane). You may evenput a mark or piece of tape at theproper wing strut position.Using the runway centerline as your guide takes care of wide or narrow runways. (Of course, this reference lineor point only works when the wings are level.)
  4. 4. On Landings Part IAvoiding UndershootsHow do you avoid undershoots? Agood pattern helps.When traffic isn’t a factor, turnbase when the point of intendedtouchdown is 45 degrees behindthe wing.At a familiar airport, you may beable to use the “crutch” of familiarlandmarks to determine properturning points. But at unfamiliarairports you won’t have such“hometown” references. The 45-degree technique will work atany airport.When there is other traffic in thepattern, you can avoid the commonproblem of the “ever-lengtheningdownwind” by starting your turn tobase just after the airplane you’refollowing turns final and passesbehind your wing (assuming that it’snot using a much slower approachspeed than yours).Experienced pilots often use a seriesof imaginary windows on approach.These “reference points in the sky”are great aids in determining whetheryour approach is within the desiredhorizontal and vertical limits.
  5. 5. On Landings Part IThe first window should beencountered just after turning final.If there are obstacles between yourimaginary window and the runway,either raise the “windows” ormove them.Your last and most important windowis the one at the runway threshold.You should be at the requiredairspeed and height to complete thelanding when you pass through thislast window.
  6. 6. On Landings Part IFlying the Right AirspeedPilots of large aircraft always determine what their approach speeds will be in advance. They calculate theaircraft’s landing weight, then look at charts for the right “reference speed,” or V-ref. The keystone V-ref, althoughdifferent on almost every approach, is based on the airplane’s stall speed and other factors at its estimatedlanding weight.Added to V-ref by the pilot is additional airspeed required to maintain an adequate safety margin whilemaneuvering in the pattern, as well as additional airspeed to compensate for wind gusts, turbulence, andwind shear.“Approach segment airspeeds,” basedon V-ref, assure that the aircrafthas just the right amount of extraairspeed margin above V-ref.Smaller aircraft do not come with V-ref tables. Some manufacturers, however, furnish recommended approachspeeds corresponding to different aircraft weights.Such tables can be developed and it is suggested that you prepare and use your own. We recommend that you usethe format in the following table but, before you fill it in, we suggest that you see Part II of On Landings and readthe accompanying handout for Part II carefully.V SpeedsLanding Weight Knots IASPre-pattern —Downwind —Base —Final —Short Final —There are rules of thumb, however:1. On downwind, fly no faster than the “top of the flap operating range” and no slower than 1.4 times thecalibrated stall speed for your airplane at its actual landing weight, or 1.4 Vso. (There are exceptions, so pleaseread Part II.)2. Maintain an airspeed no lower than 1.4 Vso until after turning final.3. Then, on final, let your airspeed decay to 1.3 Vso as you near the runway.4. If you encounter any turbulence, wind gusts, or wind shear, compensate with additional airspeed on eachsegment of the approach.
  7. 7. On Landings Part IThe Stabilized VFR ApproachMake your normal pattern entryand extend your landing gear ondownwind, if applicable. Abeam theintended landing point, reduce yourpower to the predetermined value thatworks best for your airplane. Whileholding altitude with pitch, slowthe airplane down in preparation forturning base.Then set partial flaps, if you haven’talready done so. If you have reducedpower properly, you can now trim theaircraft and set up a descent.Begin your turn to base when thepoint of touchdown is 45 degreesbehind the wing. Turn base, thenfinal, keeping all banks to 30 degreesor less.Should you need to increase your rateof descent, do so either by reducingpower or by further extending flaps toincrease drag. If you do extend flaps,remember that you’ve just modifiedyour approach configuration and thatadding power may be necessary tostay on the selected glide path at yourtargeted speed.A fundamental key to flying astabilized approach is the inter-relationship of pitch and power.At any targeted airspeed in anyconfiguration, adding more powerwill make the glide path shallower;reducing power will make it steeper.
  8. 8. On Landings Part IThis interrelationship means thatany changes to one element inthe “approach equation” must becompensated for by adjustments inthe other.So, after a glide path has beenselected, the means of staying onit and maintaining your targetedairspeed can only be achieved byadjusting pitch and power together.Experienced pilots know the powersettings and airspeeds for differentlanding weights, drag configurations,and rates of descent for theirairplanes.Then, these pilots need make onlyminor adjustments to pitch and powerto maintain the selected glide pathand airspeed.The important (if not basic) pointis never let your airspeed decaybelow the targeted airspeed for eachsegment of the approach and never letthe airplane sink below its selectedglide path.In any event, never let yourself getbehind the power curve while onlong final!One final point: full flaps should be used for all normal landings unless the manufacturer suggests otherwise.And, once flaps have been extended, they should not be retracted. That’s why it is always good practice not to goto the final flap setting until your landing is assured.• Never let the airplane sinkbelow the selected glide path.• Never let the airspeed decaybelow the target speed, and...
  9. 9. On Landings Part IThe Stabilized IFR ApproachThe same basic concepts apply to the IFR approach. First, transition the airplane to the approach configuration;that is, slow the airplane and retrim it. Do this well before you intercept the glide slope, unless traffic flowrequires otherwise.Some pilots extend their landinggear to help them slow down, thenadd flaps after the airspeed dropsinto the flap operating range. If thegear has not already been used forspeed control, extend the gear as youintercept the glide slope or reach thefinal approach fix. Additional powermay be necessary with the gear andflaps extended. Be sure to retrim foreach configuration change.You should now be able to holdthe selected airspeed and set upa stabilized rate of descent. Withthe runway in sight and a landingassured, extend final landing flaps.Retrim again and maintain positivecontrol of the aircraft, since addingflaps without promptly retrimmingcould possibly cause you to “balloon”back into the clouds.
  10. 10. On Landings Part IThe rate of descent table at theright has been adopted (for trainingpurposes) from a similar rate ofdescent table published in theUnited States Government FlightInformation Publication U.S.Terminal Procedures.
  11. 11. On Landings Part I10What If Things Go Wrong on the Approach?You should be interested to know that accidents involving undershoots are usually much more serious thanlanding long. Obviously, the energy levels involved in undershoot accidents are much higher.If ever you’re in doubt about makingthe runway, add enough power toassure a safe landing. And, of course,be sure that power will be availableby using your checklist for all pre-landing items! A significant numberof landing accidents are caused byloss of power, and many of them arerelated to some basic step the pilotsimply forgot.What Causes Most Undershoots?Often the pilot is unconsciously trying to hold altitude or make the runway using elevator alone.This sets up a mush or stall, resultingin an undershoot accident or a hardlanding on the runway itself.A perfect way to sucker yourself intothis is to shoot a long, low approach—especially in unstable air or inhigh-density altitude conditions.What can happen is that you canwind up behind the power curve withthe throttle wide open and no morepower available to stop the sink rate.In this case the only thing you cando to save the situation (tough as itis) is to ease the nose over and regainairspeed and climb capability—if youhave the altitude, distance, and lackof obstacles ahead to do it. This onlyreemphasizes the importance of usingthe proper combination of powerand pitch throughout the landingapproach.
  12. 12. On Landings Part I11Undershooting—The Key Points• Know and use the appropriate approach speeds.• Never allow yourself to get below your targeted approach speed for each segment of the approach.• Fly the proper glide path.• Add power anytime you think you’re too low or slow.• Remember the interrelationship between pitch and power.The Aim PointThe aim point is something we’ve all heard about but may not have been using. But it’s a great aid in makinggood, safe landings. The aim point is your imaginary bull’s-eye on the runway. It can be between two particularrunway lights, or wherever.It’s the reference point at the endof your selected glide path, not theactual touchdown point.
  13. 13. On Landings Part I12Glide Path SelectionOnce you’ve selected your aim point, you must also select the right glide path. Without a Visual Approach SlopeIndicator (VASI) or Instrument Landing System (ILS), this becomes a personal decision.Select a glide path that works best fora particular situation, but make sureit allows for clearance of all obstaclesand for a safe rate of descent.If the aim point appears to be movingaway from you it’s a sure sign of anundershoot.If your aim point appears to be mov-ing toward you when you’re estab-lished on final, you know that yourairplane will overshoot that point.A constant position of the aim pointin your windshield means things are“right on.”
  14. 14. On Landings Part I13A VASI is a good aid to help establisha safe glide path. Remember, though,that while all VASIs will keep youclear of obstacles, approach anglesvary. And some “complex” VASIsprovide multiple approach angles toassist everything up to jumbo jets,while many smaller airports may haveonly nonstandard VASI systems. Onesuch nonstandard system is nothingmore than three plywood (or plastic)panels to be aligned by adjusting yourglide path on approach.The FAA Aeronautical Information Manual provides a detailed description of how standard and nonstandardVASIs work. In addition, the Airport/Facility Directory provides VASI glide angle information for standardVASIs for each runway where they are installed.In Canada, comparable references are the Transport Canada Aeronautical Information Manual and the CanadaFlight Supplement.Wind and Turbulence Can Affect the GlidepathOn final, your glide path can be affected by wind, wind shear, microbursts, and other turbulence, including waketurbulence.Wind shear is a major variation inwind speed and direction betweenhorizontal layers of air.
  15. 15. On Landings Part I14Microbursts are sharp, very strongdowndrafts, associated with thunder-storms. Impossible to out-maneuverand usually invisible to the eye,they are good reasons to avoid alanding at any airport with athunderstorm nearby.Turbulence also results from airflowover nearby mountains and windsdisrupted by nearby woods, hangars,or other airport structures.Always be ready for turbulence andits effect on your approach. Whenyou find it, especially on short final,be prepared to add power and goaround if necessary. The sooner youadd power, the less likely you areto wind up between a rock and ahard place.Whenever you operate at an airport served by large aircraft, be alert for wake turbulence. Study the wake turbu-lence avoidance procedures from time to time. They, too, are published in the Transport Canada AeronauticalInformation Manual and other publications.
  16. 16. On Landings Part I15The Cross-Control StallStalls are a frequent cause of landing accidents and the deadliest of all is the cross-control stall.A cross-control stall is usually set up on base and the potential for it becomes greater in the presence of a tailwindon that leg. A tailwind creates greater groundspeed, which gives you less time to react.Add a distraction such as conflictingtraffic or a problem in the cockpitand you’re ripe for a late turn ontofinal and the potential for a cross-control stall.Making that turn to final, you don’twant to make a steep banked turnbecause you know that the stall speedincreases with bank angle.Instead, you try to increase the rate ofturn with rudder alone, all the whilekeeping your bank shallow with op-posite aileron.
  17. 17. On Landings Part I16Of course, now you’ll need more“up” elevator because the combina-tion of inside rudder and “down”aileron drag makes the nose drop.As you pull back, you slow downand, bang! There’s a stall and a snaproll toward the lower, inside wing.This situation can be avoided bygood planning, including a properlyflown pattern, proper airspeeds, anda timely go-around when things don’tfeel right.• Complete as much of your before-landing checklist as possiblebefore entering the pattern.• Look outside the cockpit forhelpful indications of wind flags,smoke, and ponds, for example.• Listen to the radio for UNICOMand ATIS advisories on landingconditions.• When you have the option, handlea direct cross-wind situation byflying a pattern that gives you aheadwind, not a tailwind, on base.
  18. 18. On Landings Part I17Hard Landings, Bounced Landings, and Loss of Directional ControlLet’s now look at three other types of landing-phase accidents: the hard landing, the bounced landing, and lossof directional control on roll-out. These are not killer mishaps like the cross-control stall and the undershoot, butthey, too, result in substantial damage, injuries, and embarrassment.Hard LandingsDrop-in or “hard” landings cause a great deal of monetary damage to airplanes each year. These accidents resultfrom several causes.You can set yourself up for a hardlanding by not looking out ahead ofthe airplane and losing your perspec-tive relative to the ground.Loss of perspective can also be theresult of improper scanning duringflare and touchdown.Remember to look outside the cock-pit—way outside. And don’t forgetto use your peripheral vision as well.It’s something you learned way backin pre-solo: to focus your attentionahead of the airplane.Hard landings are also the result ofdistractions.A typical distraction is a disturbancewith passengers in the cabin. Don’tbe distracted! The landing is thelast part of the flight, the part whereyou’re the most tired, yet it’s the pointwhere the most concentrationis required.
  19. 19. On Landings Part I18To alleviate distractions, airlines haveadopted the “sterile cockpit” concept.Below a certain altitude, all con-versation is limited only to mattersconcerning aircraft operations. It’s arule you may want to adopt.Ballooning is another cause of hardlandings.This often results from excessairspeed combined with poor flaretechnique. (Yanking back on the con-trols before touchdown can put youseveral stories above the runway withairspeed decaying rapidly.)If this happens, ease the nose overgently and add power if necessary.Remember, too, a full power go-around may be your best bet to avoida hard landing after ballooning.Another cause of hard landings, asdiscussed earlier, is trying to stretcha final approach by raising the nosewithout adding power. Also beware ofrunning out of elevator control duringflare. A typical example happenswhen you’re too slow with too muchweight up front. You may not have theflare power you need. A high descentrate makes these conditions even moreserious. Be sure you’re OK on CG.In summary, if you think you’reheaded for a hard landing—• Add power to arrest the sink rate.• Keep your wings level.• If you decide to make a go-around,make the decision sooner ratherthan later.
  20. 20. On Landings Part I19Bounced LandingsThe bounced landing, or pilot-induced oscillation (porpoising), was supposed to be cured by the introduction oftricycle landing gear. Not so. Innovative pilots keep discovering new ways to make bad landings.In a bounced landing, the airplanecomes in nose-wheel first (or for atail-dragger, main gear first) settingoff a series of motions that imitatethe jumps and dives of a porpoise—hence the name.The problem is improper aircraft atti-tude at touchdown, sometimes causedby inattention, by not knowing wherethe ground is, by mistrimming, or bytrying to force the aircraft onto therunway.No matter what the cause, the situa-tion must be corrected immediately.Ground effect, a factor from thesurface to a height of about half theplane’s wing span, decreases elevatorcontrol effectiveness and increasesthe effort required to raise the noseand hold the airplane off. Not enoughelevator (or stabilator) trim can resultin a nose-low contact with the run-way and a porpoise.
  21. 21. On Landings Part I20The secret to a good landing is properaircraft attitude at touchdown. Fortricycle gear planes, it’s the attitudethat assures that the main wheels willtouch before the nose wheel. You’llneed to develop a feel for this attitudein your particular aircraft and stayproficient at it. You’ll also need toknow what it “feels like” at all com-binations of weight and CG.Porpoising can also be caused byimproper airspeed control. Usually, ifan approach is too fast, the airplanefloats and the pilot tries to force it onthe runway when the airplane stillwants to fly.A gust of wind, a bump in the run-way, even a slight tug on the wheelwill send the aircraft aloft again.What to do?First, don’t push the nose over. Easeit over and re-land, this time hold-ing the proper pitch attitude untilthe aircraft touches down. Add backpressure continually as the aircraftslows during the flare.
  22. 22. On Landings Part I21Too many airplanes have beenpranged because of the pilot’s desireto put the airplane on the ground. Ago-around may be the answer in somecases of porpoising.To avoid porpoising:• Always trim the airplane for astabilized approach.• Avoid excess airspeed and “float-ing.”• Don’t be distracted.• Maintain proper pitch attitude.• Stay proficient.
  23. 23. On Landings Part I22Loss of Directional ControlEngineers also thought tricycle landing gear would eliminate directional control problems and ground looping.Not so.(For those who aren’t familiar withthis nemesis, a ground loop is anuncontrolled turn, often violent—usu-ally on landing and roll-out.)How to avoid loss of directionalcontrol? Recognize and correct prob-lems early. Stop any incipient turnor swerve almost before it starts. Getright on it.Also, use your controls to their bestadvantage. Keep the weight of tricyclegear aircraft on the mains with eleva-tor back pressure—this also desensi-tizes the nosewheel.
  24. 24. On Landings Part I23In tail-draggers, full back stick putsmore weight on the tailwheel for bet-ter directional control.Lack of sufficient back pressure canmultiply the effects of small ruddermovements (or reactions to cross-winds)—overcorrections that caninduce trouble.If you get in trouble, close the throttle,apply back pressure, and regaincontrol.Crosswinds can be a real problem.Remember, in a crosswind landing,the longitudinal axis of the airplanemust remain parallel to the runwaycenterline, as must the flight path ofthe airplane.If you don’t do both, strong side loadsmay be exerted on the landing gear,and a ground loop could occur (result-ing in even higher side loads).
  25. 25. On Landings Part I24Proper crosswind technique is a must.In the case of a left crosswind, the leftwing must be lowered into the windand this control input countered withright rudder to maintain the propertrack down to the runway. Again, thelongitudinal axis of the airplane mustbe aligned with the flight path which,we hope, is parallel to the runwaycenterline.By the way, you should know the crosswind limitations of your airplane and yourself. In some cases, it is best tostay on the ground, or, if airborne, to locate another runway more aligned with the wind.One of the worst ego bruises occurs when the pilot tries to clear the runway before he or she has slowed downenough. This is even more of a problem in some crosswind conditions.Simply following the yellow exit line may lead to an unplanned cross-country. A much better technique is to stayon the runway centerline until you’ve slowed down to taxi speed.Face it, there’s only one principalcause for loss of directional con-trol—pilot error. It’s not only lack ofknowledge of the “basics.” Recentstudies also point to preoccupation,stress, fatigue, or just being on a“mental holiday.”Use the sterile cockpit rule on your-self. Think ahead of the airplane onevery approach. Continue to fly theairplane after touchdown. And stayproficient.Worst of all, don’t freeze. Rememberthe saying on the mayonnaise jar,“keep cool but do not freeze.” Stay ontop of the situation.Panic can also result in a reversion to“driving response,” or trying to steerthe aircraft down the runway withthe control wheel. That wheel has nopurpose in steering on the ground and“driving response” can lead to loss ofcontrol.
  26. 26. On Landings Part I25To summarize, directional controlaccidents can be greatly reduced if, aspilots, we follow these simple rules:• Maintain proficiency.• Stay ahead of the airplane.• Avoid wheelbarrowing by holdingbackpressure on the controls dur-ing roll-out.• Keep your flight path and longitu-dinal axis parallel to the runwaycenterline.• Double check wind conditions onshort final.• Stay within the demonstratedcrosswind capabilities for both youand the airplane.• Slow the airplane down beforetaxiing clear.• Keep your thoughts on the land-ing; that is, don’t be distracted.• “Keep cool but do not freeze.”Note: The suggestions and “rules” given in this handout are intended to be helpful aids only and are not intended to replace orsupersede the recommendations of the aircraft manufacturer.About This SeriesThe purpose of this series of Federal Aviation Administration (FAA) safety publications is to provide the avia-tion community with safety information that is informative, handy, and easy to review. Many of the publicationsin this series summarize material published in various FAA advisory circulars, handbooks, other publications,and audiovisual products developed by the FAA and used by the FAA Safety Team (FAASTeam) for educationalpurposes.Some of the ideas and materials in this series were developed by the aviation industry. The FAASTeam acknowl-edges the support of the aviation industry and its various trade and membership groups in the production of thisseries. We would like to acknowledge the contributions of the late William K. Kershner, technical advisor. Also,special thanks to Drew Steketee and Cassandra Bosco, writing and editing; James Gross, illustrations and graph-ics, layout and design; Gary S. Livack, overall project coordinator; and Ken Johnson, executive producer.Comments regarding these publications should be e-mailed to ProductManager@FAASafety.gov.Additional copies of this publication may be downloaded or printed at http://FAASafety.gov.
  27. 27. On Landings Part I26