Traffic Patterns, Collision Avoidance, Wake Turbulence

The traffic pattern is a rectangle flown around the runway at a common altitude. At an airport without an operating control tower, the rule is left turns. Section 91.126 says each pilot of a powered fixed-wing airplane "must make all turns to the left unless the airport displays approved light signals or visual markings indicating that turns should be made to the right, in which case the pilot must make all turns to the right" 1. The sectional chart prints right traffic as "RP" with the runway number at the bottom of the airport data block. The Chart Supplement lists it as well 2.

The legs

The legs in order are:

• upwind
• crosswind
• downwind
• base
• final.

The Airplane Flying Handbook says the pattern altitude "is usually 1,000 feet above the elevation of the airport surface" and that "the use of a common altitude at a given airport is the key factor in minimizing the risk of collisions at airports without operating control towers" 3. The AIM's figure for propeller-driven airplanes is 1,000 feet AGL. Large and turbine airplanes fly 500 feet higher 4. The Chart Supplement lists the pattern altitude where it differs.

The downwind leg runs parallel to the runway, opposite the landing direction. The pilot flies it "approximately 1/2 to 1 mile out from the landing runway and at the specified traffic pattern altitude." The pilot holds pattern altitude "until at least abeam the approach end of the landing runway," then reduces power and begins the descent. The pilot turns base at a point "approximately 45° from the approach end of the runway" behind the wing 5. The pilot completes the turn to final at least a quarter mile from the runway 6.

The entry

The standard entry at a non-towered airport is a 45-degree leg to the downwind, aimed at the midpoint of the runway. The pilot flies it at pattern altitude. The handbook says "the traffic pattern is normally entered at a 45° angle to the downwind leg, headed toward a point abeam the midpoint of the runway to be used for landing." The entry leg is long enough "to provide a clear view of the entire traffic pattern." The handbook adds that "entries into traffic patterns while descending create specific collision hazards and should be avoided" 7. AC 90-66C says the same: "Aircraft should always enter the pattern at pattern altitude, especially when flying over midfield and entering the downwind directly" 8.

The departure

After takeoff the airplane climbs straight ahead. An airplane staying in the pattern turns crosswind "beyond the departure end of the runway within 300 feet of the traffic pattern altitude." An airplane leaving the pattern continues "straight out or exit[s] with a 45° turn (to the left when in a left-hand traffic pattern or to the right when in a right-hand traffic pattern) beyond the departure end of the runway after reaching the traffic pattern altitude" 9. On crosswind, after a takeoff into the wind, the pilot heads slightly into the wind to keep the track square to the runway. The AC adds one duty to the departure: "Pilots need to be aware of any traffic entering the traffic pattern prior to commencing a turn" 10.

An airplane arriving from the upwind side of the airport cannot join the 45 without crossing the runway. The handbook gives two ways. The preferred way has five steps:

• "announce intentions and cross over midfield at least 500 feet above pattern altitude (normally 1,500 feet AGL),"
• fly "well clear of the pattern—approximately 2 miles,"
• scan
• descend to pattern altitude
• turn back to enter on the 45.

The alternate way is "to enter on a midfield crosswind at pattern altitude, carefully scan for traffic, announce intentions, and then turn downwind," and "this technique should not be used if the pattern is busy" 11. AC 90-66C repeats the warning: "descending into the traffic pattern can be dangerous, as one aircraft could descend on top of another aircraft that is already in the pattern" 12. Where large or turbine airplanes use the airport, the pilot crosses at 2,000 feet AGL, above their pattern.

The segmented circle

The segmented circle is the airport's set of visual signals, for pilots with a radio and for pilots without one. The circle sits where it is visible from the air and from the ground. The wind indicator, "a wind cone, wind sock, or wind tee," sits near the runway, and "the large end of the wind cone/wind sock points into the wind." Traffic pattern indicators are "arranged in pairs in conjunction with landing strip indicators and used to indicate the direction of turns when there is a variation from the normal left traffic pattern" 13. The AIM says "if the pilot will mentally enlarge the indicator for the runway to be used, the base and final approach legs of the traffic pattern to be flown immediately become apparent" 14.

A tetrahedron, where the airport has one, shows landing direction, not wind. The AIM cautions that in "very light or calm wind conditions" the tetrahedron "may not be aligned with the designated calm-wind runway" 15.

Choosing the runway

The runway is the one most nearly into the wind, and the one the traffic uses. AC 90-66C: "Landing and takeoff should be accomplished on the operating runway most nearly aligned into the wind" 16. It adds: "If other traffic is present in the pattern, arriving or departing aircraft should use the same runway as these aircraft" 17.

The AC sets the order of work. Before entering, "the pilot can check wind and landing direction indicators while at an altitude above the traffic pattern, or by monitoring the communications of other traffic that communicate the runway in use." Then the pilot goes "to a point well clear of the pattern before descending to and entering at pattern altitude" 18. A calm-wind runway is a local convention. The pilot listens before assuming it is in use.

ATIS is a recorded broadcast at busy towered airports. The AIM defines it as "the continuous broadcast of recorded noncontrol information in selected high activity terminal areas." The broadcast carries:

• the airport name
• a phonetic letter
• the time of the weather
• the wind
• the visibility
• the sky condition
• the temperature and dew point
• the altimeter
• the approach and runway in use.

The recording "must be updated upon the receipt of any official hourly and special weather," and the tower makes a new recording for a runway change. Pilots listen "whenever ATIS is in operation" and tell the controller the letter on first contact 19.

AWOS and ASOS are automated weather stations. No controller speaks on them. The AIM describes AWOS as "various sensors, a processor, a computer-generated voice subsystem, and a transmitter to broadcast local, minute-by-minute weather data directly to the pilot." The message runs 20 to 30 seconds and is "updated each minute," and "there is no two-way communication capability" 20. The Chart Supplement and the sectional chart list the frequency.

The CTAF

The Common Traffic Advisory Frequency is where pilots at a non-towered airport report their positions to each other. The AIM: "A CTAF is a frequency designated for the purpose of carrying out airport advisory practices while operating to or from an airport without an operating control tower." Inbound pilots "should monitor and communicate as appropriate on the designated CTAF from 10 miles to landing." Departing pilots monitor "from start-up, during taxi, and until 10 miles from the airport" 21. The self-announce points are:

• 10 miles out, with position, altitude, and intention
• entering downwind
• turning base
• turning final
• leaving the runway.

AC 90-66C gives the words: "Entering left/right downwind for runway [XX];" "On the left/right downwind for runway [XX];" "On left/right base for runway [XX];" "On final for runway [XX]" 22. The airport name opens and closes each call. The call gives the airplane type and call sign, not its color. "Any traffic in the area, please advise" is not a call and "should not be used under any condition" 23. The AC asks pilots to "avoid using the words 'to' and 'for' whenever possible," because they sound like runway numbers, and not to announce a landing sequence 24.

Listening first lets the pilot enter the pattern knowing the runway, the wind, and the position of each airplane. The AIM warns that "other aircraft may not have communication capability or, in some cases, pilots may not communicate their presence or intentions" 25. The AC says the rules "generally do not require the use of two-way radios" at these airports, so the pilot is "especially vigilant for other aircraft while operating in the traffic pattern" 17.

The flight of N9221D and N10510

On March 7, 2023, at 2 in the afternoon, two airplanes collided nearly head-on at 465 feet over a lake at Winter Haven, Florida. Both were on the base leg for runway 29 at Winter Haven Regional Airport. All four people aboard died.

One airplane was a 1945 Piper J3C-65 Cub on floats, N10510. A 78-year-old instructor with 25,000 hours sat in the front seat, and a 67-year-old commercial pilot sat in the back. They flew back toward Jack Brown's Seaplane Base after a local flight. The seaplane base is on the north shore of the lake, about 500 feet south of the runway 11 threshold.

The other airplane was a Piper PA-28-161 Warrior, N9221D, from a flight school in Lakeland. A 23-year-old instructor with 489 hours sat in the right seat, and a 19-year-old private pilot with 215 hours sat in the left. They practiced power-off 180-degree accuracy landings to runway 29 26.

The weather was clear:

• 10 miles visibility
• a few clouds at 4,100 feet
• wind from 300 degrees at 10 knots.

The Warrior was on its fourth power-off 180. The pilot announced the turn to base on the CTAF. The Cub had no radio, and the rules did not require one. Shortly after the call, the two airplanes collided.

A witness saw the Cub heading south, turning west, lower than the Warrior. The NTSB's video study put the Cub at 46 knots groundspeed and the Warrior at 80. Both descended, the Cub at 456 feet per minute and the Warrior at 792. Surveillance video showed "neither airplane made altitude or heading changes immediately before the collision." The Warrior's right wing broke off. Both airplanes fell into the lake east of the approach end of runway 29.

Neither airplane had a traffic display. Only the Warrior had ADS-B Out. The examination found no mechanical failure in either airplane. The NTSB's video study found that, "given the two flight paths and the nearly head-on impact, the front-seat pilot of the J3C and the right-seat flight instructor of the PA-28 should have been able to detect the other airplane," and that the search "likely would have been made more difficult by the complex background of sky and ground."

The probable cause: "The failure of both flight crews to see and avoid each other while operating in the airport environment" 26. After the accident, the Chart Supplement entry for Winter Haven gained a remark. The remark says numerous airplanes operate without radios near the airport and the seaplane base.

Where the accident could have been prevented

Four pilots, two of them instructors, flew in clear weather over an airport with a working CTAF and a working weather station. No mechanical failure and no weather contributed. Each step below is a point where one crew could have seen the other. Its PAVE category is beside it.

The first sentence of the right-of-way rule states the whole duty. Section 91.113(b): "When weather conditions permit, regardless of whether an operation is conducted under instrument flight rules or visual flight rules, vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft." The second sentence sets the manner of giving way: the pilot "may not pass over, under, or ahead of it unless well clear" 27. A separate rule makes any close pass an offense on its own: "No person may operate an aircraft so close to another aircraft as to create a collision hazard" 28.

The order of precedence

An airplane in distress "has the right-of-way over all other air traffic" 29. After that rule, precedence goes by category and then by geometry.

When two of the same category converge "at approximately the same altitude (except head-on, or nearly so)": "the aircraft to the other's right has the right-of-way." Different categories rank as follows 30:

• a balloon has the right-of-way over any other category
• a glider has the right-of-way over each powered category
• a towing or refueling airplane has the right-of-way over each other powered category, including an airship
• an airship has the right-of-way over the remaining powered categories.

The order is the least maneuverable first. The Warrior yields to all of them.

Head-on, overtaking, landing

Head-on, or nearly so: "each pilot of each aircraft shall alter course to the right." Overtaking: "Each aircraft that is being overtaken has the right-of-way and each pilot of an overtaking aircraft shall alter course to the right to pass well clear" 31. Both rules require a turn to the right. On the road a driver passes on the left. In the air the overtaker passes on the right.

Landing: airplanes "on final approach to land or while landing, have the right-of-way over other aircraft in flight or operating on the surface." When two or more airplanes approach to land, "the aircraft at the lower altitude has the right-of-way." Each half carries a limit. The landing airplane cannot "force an aircraft off the runway surface which has already landed," and the lower airplane cannot "cut in front of another which is on final approach to land or to overtake that aircraft" 32.

The handbook applies the limit to the turn to final: "If the turn to final would create a collision hazard, a go-around or avoidance maneuver is in order" 33. A straight-in arrival has no particular priority over the pattern. AC 90-66C says pilots choosing a straight-in "do not have a particular priority over other aircraft in the traffic pattern" 34. The Pilot's Handbook adds a limit: "Even if entitled to the right-of-way, a pilot should yield if another aircraft seems too close" 35.

Section 91.119 sets three minimum altitudes. None of them applies "when necessary for takeoff or landing." The first applies everywhere: "an altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface." The second applies over a congested area: "over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft." The third applies everywhere else: "an altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure" 36.

Reading the three minimums

The first minimum is a judgment, and it applies at each altitude. A Warrior at 600 feet over a forest with no clearing is above the 500-foot minimum and below the first one. The second minimum starts at the highest obstacle within 2,000 feet, not at the ground. A 300-foot tower inside that radius puts the minimum at 1,300 feet above the ground.

The third minimum, over open water and sparse land, is a distance, not a height. Flight 400 feet above a boat is a violation. Flight 500 feet to the side of a boat is not. The regulation does not define "congested." The pilot who is unsure treats the area as congested.

The student flies the ground reference maneuvers between 600 and 1,000 feet AGL over open land because of these minimums. The emergency landing minimum, the first one, is the one the instructor asks about when the airplane is low over a field.

The eye detects traffic only while the eye is still. The Pilot's Handbook: "Effective scanning is accomplished with a series of short, regularly spaced eye movements that bring successive areas of the sky into the central visual field. Each movement should not exceed 10°, and each should be observed for at least 1 second to enable detection" 35. A sweep across the windshield detects nothing. The eye classifies an object only within about 10 to 15 degrees of its center of vision 37.

The airplane that does not move in the windshield

An airplane on a collision course stays in the same place in the windshield. AC 90-48E calls this behavior the blossom effect: "two aircraft on a collision course will appear to be virtually motionless to each other. The other aircraft will remain in a seemingly stationary position, without appearing to move or grow in size for a relatively long time, and then suddenly bloom into a huge mass filling one of the windows." The AC adds that "a large bug smear or dirty spot on the windshield can hide a converging plane until it is too close to be avoided" 37. The rule follows from the physics. An airplane that drifts across the windshield will pass. The airplane that holds its bearing is the one to turn away from.

Once the pilot sees the target, time is short. The AC's table gives:

• 0.1 second to see the object
• 1.0 second to recognize an airplane
• 5.0 seconds to become aware of the collision course
• 4.0 seconds to decide which way to turn
• 0.4 second for the muscular reaction
• 2.0 seconds for the airplane to respond.

The total is "12.5 seconds to identify, react, and avoid a midair collision" 38.

Blind spots and clearing

The Warrior is a low-wing airplane. AC 90-48E: "High-wing airplanes have restricted visibility above, while low-wing airplanes have limited visibility below. The worst-case scenario is a low-wing airplane flying above a high-wing airplane" 39. The AIM's clearing procedures cover the turn and the descent: "Low-wing airplane. Momentarily lower the wing in the direction of the intended turn and look." In climbs and descents, the AIM calls for "gentle banks, left and right at a frequency which permits continuous visual scanning" 40. Clearing turns come before each maneuver. The Pilot's Handbook says the same for the high wing: raise it toward the turn and look before turning 41.

The Airplane Flying Handbook says midair collisions "generally occur during daylight hours." "Most mid-air collisions occur under good visibility." "A mid-air collision is most likely to occur between two aircraft going in the same direction." "Nearly all accidents occur at or near uncontrolled airports and at altitudes below 1,000 feet" 42. The chapter closes: "Most reported mid-air collisions occur during the final or short-final approach leg of the airport traffic pattern" 43.

The pattern is the highest-risk airspace a student flies. Final and short final are the highest-risk part of it. The Winter Haven collision was on base, one turn short of final.

Being seen

The FAA's Operation Lights On asks pilots "to turn on their landing lights when operating below 10,000 feet, day or night, especially when operating within 10 miles of any airport" 44. AC 90-48E names the runway entry procedure Lights, Camera, Action 45:

• landing light and other lights on
• transponder on
• call sign said.

AC 90-66C adds the strobes: "You should keep lights and strobes on" 46. The pilot turns on the strobes and the landing light in the pattern and within 10 miles of any airport.

Distraction

The AIM lists the first limit on the scan as "reduced scan frequency due to concentration on flight instruments or tablets and distraction with passengers" 47. The AC says the distraction of maneuvering "takes away from scanning for traffic," and that "a significant number of midair collisions and NMACs have occurred within towered and non-towered airport traffic patterns" 48. The pilot looks outside in the turns and does tasks on the straight legs. The pilot does the before-landing checklist on downwind, before the base turn, in the handbook's order: "when flying on the downwind leg, the pilot should complete all before-landing checks" 5. Three things wait until the turn is complete:

• the radio
• the tablet
• the passenger.

Each wing that makes lift sheds two vortices from its tips. The AIM: "Wake turbulence is a function of an aircraft producing lift, resulting in the formation of two counter-rotating vortices trailing behind the aircraft." The hazard is roll: "Wake turbulence can impose rolling moments exceeding the roll-control authority of encountering aircraft" 49. The AIM says "it is more difficult for aircraft with short wingspan (relative to the generating aircraft) to counter the imposed roll induced by vortex flow" 50. A Warrior's span is short beside an airliner's.

The strength of the vortex depends on the airplane that made it. "The vortex strength from an aircraft increases proportionately to an increase in operating weight or a decrease in aircraft speed," and a dirty configuration breaks up the wake faster, so "the greatest vortex strength occurs when the generating aircraft is HEAVY, CLEAN, and SLOW" 51. A jet on final with flaps and gear out is heavy and slow. A jet climbing out clean is heavy, clean, and slow. The climb-out is the worse of the two.

Where the vortices go

"An aircraft generates vortices from the moment it rotates on takeoff to touchdown." The vortices "sink at a rate of several hundred feet per minute, slowing their descent and diminishing in strength with time and distance," and near the ground, "within 100 to 200 feet," they "move laterally over the ground at a speed of 2 or 3 knots" 52. The AIM's figure shows the flight path 500 to 1,000 feet above the settled vortices.

A crosswind changes the drift. "A crosswind will decrease the lateral movement of the upwind vortex and increase the movement of the downwind vortex," so "a light wind with a cross-runway component of 1 to 5 knots could result in the upwind vortex remaining in the touchdown zone." A tailwind moves the vortices forward into the touchdown zone. "THE LIGHT QUARTERING TAILWIND REQUIRES MAXIMUM CAUTION" 53. The Pilot's Handbook describes the worst case: the vortices "could be all present along a significant portion of the final approach and extended centerline and not just in the touchdown zone" 54.

The AIM prints the rule for the area in capitals: "AVOID THE AREA BELOW AND BEHIND THE WAKE GENERATING AIRCRAFT, ESPECIALLY AT LOW ALTITUDE WHERE EVEN A MOMENTARY WAKE ENCOUNTER COULD BE CATASTROPHIC" 55. The procedures follow from where the vortices are 56:

• landing behind a larger airplane on the same runway: "stay at or above the larger aircraft's final approach flight path, note its touchdown point, land beyond it"
• landing behind a departing larger airplane: note its rotation point and "land well prior to rotation point"
• departing behind a larger airplane: "rotate prior to the larger aircraft's rotation point," climb above its climb path, and turn upwind, clear of its wake
• after a larger airplane's low approach, missed approach, or touch-and-go: wait "at least 2 minutes" before the takeoff or landing.

The tower's phrase is "CAUTION - WAKE TURBULENCE." It is information, not separation. "Whether or not a warning or information has been given, however, the pilot is expected to adjust aircraft operations and flight path as necessary to preclude serious wake encounters" 57. Accepting any of three things "is an acknowledgment that the pilot will ensure safe takeoff and landing intervals and accepts the responsibility for providing wake turbulence separation" 58. The three are:

• traffic information
• an instruction to follow another airplane
• a visual approach clearance.

The controller's wake separation minimums are for airplanes the controller separates. A Warrior told to follow the airliner separates itself. Two minutes or more behind a heavy airplane is the time the vortices need to settle and drift.

Helicopters

A hovering helicopter pushes its rotor wash outward along the ground. The AIM: the outwash reaches "to a distance approximately three times the diameter of the rotor," and "pilots of small aircraft should avoid operating within three rotor diameters of any helicopter in a slow hover taxi or stationary hover" 59. In forward flight a helicopter sheds a pair of vortices, as a large airplane does. A Warrior taxiing past a helicopter on the ramp stays three rotor diameters from it.

Wind shear is "a sudden, drastic change in wind speed and/or direction over a very small area." Near the ground it comes with "passing frontal systems, thunderstorms, temperature inversions, and strong upper level winds." The Pilot's Handbook gives the signature: "a tailwind quickly changing to a headwind causes an increase in airspeed and performance. Conversely, a headwind changing to a tailwind causes a decrease in airspeed and performance" 60.

On final, three things appear as a sudden airspeed change with no control input:

• a gust front
• a thermal
• a rotor off a hangar or a tree line.

The response has three parts:

• power
• pitch for the target speed
• the go-around decision, made early.

The handbook lists wind shear among the reasons a go-around is the normal outcome 61. The Warrior's manual says that in high winds, "particularly in strong crosswinds, it may be desirable to approach the ground at higher than normal speeds with partial or no flaps" 62.

The towered pattern

At a towered airport the tower controls the pattern. Section 91.126(d) requires "two-way radio communications" with the tower, "established prior to 4 nautical miles from the airport, up to and including 2,500 feet AGL" 63. The AIM says the pilot makes the initial call "about 15 miles from the airport," that the tower "will issue clearances or other information for aircraft to generally follow the desired flight path," and that "in all instances, an appropriate clearance must be received from the tower before landing" 64. The tower sequences the airplanes. The tower does not fly them.

No clearance removes the see-and-avoid duty. Section 91.113(b) applies "regardless of whether an operation is conducted under instrument flight rules or visual flight rules," radar or not 27. Each accepted instruction adds wake responsibility to the pilot and removes none 58. AC 90-66C says the same for the non-towered case: "The use of any traffic pattern procedure does not alter the responsibility of each pilot to see and avoid other aircraft" 46. At the towered airport, "follow the Cessna on base" means find the Cessna first.

The Airplane Flying Handbook defines the stabilized approach: "one in which the pilot establishes and maintains a constant-angle glide path towards a predetermined point on the landing runway. It is based on the pilot's judgment of certain visual clues and depends on maintaining a constant final descent airspeed and configuration." For a piston airplane the criteria are 65:

• glide path, "typically a constant 3 degrees to the touchdown zone"
• heading, tracking the centerline "with only minor heading/pitch changes," bank "normally limited to 15 degrees once established on final"
• airspeed "within +10/-5 KIAS of the recommended landing speed"
• configuration, flaps as required, gear down, in trim
• descent rate, 500 to 1,000 feet per minute, with minimal adjustment.

The pilot manages the energy so that no large correction is needed close to the ground. The handbook sets the decision altitude: "Typically, pilots go-around if unable to establish a stabilized approach by 500 ft above airport elevation in visual meteorological conditions." It adds: "For a typical GA piston aircraft in a traffic pattern, an immediate go-around should be initiated if the approach becomes unstabilized below 300 ft AGL" 66.

The go-around is the normal outcome

"A go-around is a normal maneuver that is used when approach and landing parameters deviate from expectations or when it is hazardous to continue." The listed reasons include 61:

• ATC
• a hazard on the runway
• overtaking another airplane
• wind shear
• wake turbulence
• mechanical failure
• an unstable approach.

The pilot plans the go-around on each approach and briefs it before the approach begins:

• the power
• the pitch
• the flap retraction
• the climb speed
• where the airplane goes.

The danger is in the delay. "The go-around maneuver is not inherently dangerous in itself. It becomes dangerous only when delayed unduly or executed improperly." The handbook names the two sources of delay: "Landing expectancy or set—the anticipatory belief that conditions are not as threatening as they are and that the approach is sure to terminate with a safe landing," and "Pride—the mistaken belief that the act of going around is an admission of failure" 67.

A go-around begun at 300 feet is a climb. A go-around begun in the flare, or after a bounce, is a low-speed, nose-high, full-power maneuver near the stall. The loss-of-control and stall accidents in the pattern begin there. The pilot decides early and high.

A crosswind does two things. In the air it drifts the airplane off the runway track. On the ground it turns the nose into the wind. The handbook: "an airplane has a greater profile or side area behind the main landing gear than forward of the gear," so "the airplane tends to turn or weathervane into the wind." The pilot computes the crosswind component from the chart before each takeoff and landing and plans the correction from it. The handbook says "it is imperative that pilots determine the maximum crosswind component of each airplane they fly and avoid operations in wind conditions that exceed the capability of the airplane" 68.

The crosswind takeoff

The takeoff begins with full aileron. "If a crosswind is present, the pilot should apply full aileron pressure into the wind while beginning the takeoff roll," holding it "until the ailerons become effective." As speed builds the pilot eases the aileron to the amount that keeps the wings level. A raised upwind wing produces skipping, "a series of very small bounces caused by the airplane attempting to fly and then settling back onto the runway," and "this side-skipping imposes severe side stresses on the landing gear and may result in structural failure." In a significant crosswind the pilot holds the main wheels on "slightly longer than in a normal takeoff so that a smooth but very definite lift-off can be made" 69. The downwind wheel can leave the ground first, and that sequence is correct.

The crosswind landing

Two methods correct the drift on final. "The crab method may be easier for the pilot to maintain during final approach," but "it requires judgment and precise timing when removing the crab immediately prior to touchdown." "The wing-low method is recommended in most cases." The usual technique is "to use the crab method initially and smoothly transition to the wing-low method before the round out is started" 70.

In the wing-low sideslip, the low wing stops the drift and opposite rudder holds the nose on the centerline. The method "keeps the airplane's ground track and longitudinal axis aligned with the runway centerline throughout the final approach, round out, touchdown, and after-landing roll," and "the initial touchdown occurs on the upwind main wheel." The downwind wheel settles as the speed decays 71. The pilot holds the aileron in through the rollout and adds more as the airplane slows, because the weathervaning tendency grows as the speed drops.

LAHSO is "Land and Hold Short Operations," a clearance to land "and hold short of an intersecting runway, an intersecting taxiway, or some other designated point on a runway." The AIM says: "Pilots may accept such a clearance provided that the pilot-in-command determines that the aircraft can safely land and stop within the Available Landing Distance (ALD)." "The pilot-in-command has the final authority to accept or decline any land and hold short clearance." In the same paragraph: "Student pilots or pilots not familiar with LAHSO should not participate in the program" 72. A student flying solo declines LAHSO. Declining costs nothing.

Accepting one

The Chart Supplement publishes the ALD, and the controller gives it on request. The AIM asks for the comparison before the flight: "As part of a pilot's preflight planning process, pilots should determine if their destination airport has LAHSO. If so, their preflight planning process should include an assessment of which LAHSO combinations would work for them given their aircraft's required landing distance" 73. The pilot compares the Warrior's landing distance over a 50-foot obstacle, with the school's margin, against the ALD. If the distance does not fit with margin, the answer is "unable."

A pilot who declines "is expected to promptly inform air traffic, ideally even before the clearance is issued." Once the pilot accepts it, the clearance "must be adhered to, just as any other ATC clearance." A go-around is still available: "A LAHSO clearance does not preclude a rejected landing," and after one, "the pilot should maintain safe separation from other aircraft or vehicles, and should promptly notify the controller" 74. The crossing runway has traffic on it. The go-around off a LAHSO clearance flies the expected path, clear of that traffic. The pilot briefs that path before accepting the clearance.

The rectangular course

The rectangular course is the traffic pattern flown around a field. The handbook: "The rectangular course is a training maneuver in which the airplane maintains an equal distance from all sides of the selected rectangular references. The maneuver is accomplished to replicate the airport traffic pattern that an airplane typically maneuvers while landing." The wind correction is the same as in the pattern. A crab on each straight leg holds the track, and the groundspeed sets the bank in each turn. "Where groundspeed is the fastest, such as when the airplane is headed downwind, the bank angle should be steepest. Where groundspeed is the slowest, such as when the airplane is headed upwind, the bank angle should be shallow" 75. The turn from downwind to base is the steepest turn in the pattern for the same reason. The turn from base to final, into the wind, is the shallowest.