POH Archives - FLYING Magazine https://cms.flyingmag.com/tag/poh/ The world's most widely read aviation magazine Fri, 01 Mar 2024 01:38:21 +0000 en-US hourly 1 https://wordpress.org/?v=6.6.1 Practice Crosswind Landings Whenever You Can https://www.flyingmag.com/practice-crosswind-landings-whenever-you-can/ https://www.flyingmag.com/practice-crosswind-landings-whenever-you-can/#comments Fri, 01 Mar 2024 01:38:14 +0000 https://www.flyingmag.com/?p=196710 Since most airports are designed with runways aligned into prevailing winds, many pilots don’t get much work with crosswind takeoffs and landings.

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“How are your crosswind landings?”

“We’re about to find out.”

Have you ever had this conversation in the aircraft? It often occurs when you listen to the one-minute weather or ATIS and learn the winds are blowing at an angle to the runway rather than parallel to the direction of landing. As a result, there is the increased potential for drifting off the centerline—unless the pilot is prepared to take prompt and corrective action. As we go into the winter months, winds tend to kick up across the U.S., making it more likely for you to encounter a crosswind.

Since most airports are designed with runways aligned into prevailing winds, many pilots don’t get much practice with crosswind takeoffs and landings—and it shows. A search of accident and incident reports compiled by the National Transportation Safety Board shows pages upon pages of landing accidents and incidents where a crosswind got the better of a pilot.

In FAA Advisory Circular 150/5300-13, it is noted that “generally, the smaller the airplane, the more it is affected by wind, particularly crosswind components. Crosswinds are often a contributing factor in small airplane accidents.” The FAA has devoted several pages in the Airplane Flying Handbook and the Pilot’s Handbook of Aeronautical Knowledge to giving pilots tools for landing in crosswinds.

Determining the Crosswind Component

Many POHs also have a performance chart that allows the pilot to determine the crosswind and headwind component.

The first step is to determine what direction the wind is coming from and note the velocity. Next, select the runway that gives you the smallest angle between the wind direction and the runway. For example, if the wind is reported as 300 at 15 knots and the runway options are 34/16, 34, (Runway 340) the angle difference is 40 degrees. If you select Runway 16, there’s a 140-degree angle.

Make It Visual

This is where the mechanical E6B flight computer shines. Look at the wind side of the unit, placing the runway heading under the True Index—300 is to the left. Using Runway 34 will mean a wind from the left side of the nose.

Now put 160 under the True Index—300 is now a tailwind from the right. Taking off and landing with a quartering tailwind is dangerous and should be avoided.

Demonstrated Crosswind Component

Before an airplane is type certificated by the FAA, it is flight-tested to ensure it meets certain requirements. Among these is the demonstration of being satisfactorily controllable with no exceptional degree of skill or alertness on the part of the pilot in 90-degree crosswinds up to a velocity equal to 0.2 VSO. This means a wind speed of two-tenths of the airplane’s stalling speed with power off and in landing configuration. Often this information is placarded in the aircraft.

According to the POH for the Cessna 172S, the crosswind component chart has fine print reading “maximum demonstrated crosswind velocity is 15 knots (not a limitation).” This means 15 knots was the maximum component the manufacturer tested to, so it does not necessarily mean operations with a great crosswind are particularly dangerous or difficult. It greatly depends on the type of airplane and the experience, skill, and proficiency of the pilot. However, in Chapter 9 of the Airplane Flying Handbook, the FAA offers the warning that “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.”

Crosswind Technique

Both crosswind landings and takeoffs require the pilot to put aileron deflection into the wind to maintain directional control. As control effectiveness (especially ailerons) increases with a rise in airflow over the wings, landings tend to be more difficult, because control effectiveness is reduced as the aircraft slows down.

There are two methods for the crosswind approach and landing: the crab method and sideslip method.

In the crab method, the pilot aligns the airplane’s ground track with the centerline of the runway, with the nose of the aircraft pointed into the wind. The pilot makes small adjustments, maintaining the crab angle until just before touchdown. The pilot must use rudder control to align the longitudinal axis of the airplane with the runway centerline to avoid side loading the landing gear. Ideally, the pilot will straighten out the airplane just in time for the upwind wheel to touch down a moment before the downwind wheel. This takes practice to get right. If the pilot is too early or too late, side loading can occur. Too much side load and there can be gear damage and possibly a wingtip strike.

Using the sideslip method, the pilot first uses the rudder to align the airplane on runway heading then notes the amount of drift occurring as a result of the crosswind. The pilot then adjusts the bank angle, with some calling it “leaning into the wind” to keep the airplane’s longitudinal access and ground track aligned with the runway centerline.

You need to hold that alignment through final approach, roundout, touchdown, and rollout, remembering that as the aircraft’s speed diminishes, so does flight control effectiveness. If you’re struggling, running out of rudder on final, it’s probably only going to get worse. The prudent thing to do is go around.

The roundout is made like a normal landing approach, but the application of a crosswind correction is continued as necessary to prevent drifting.

Some pilots use a combination of the two methods, using the slip into the wind and opposite rudder to keep the aircraft from turning into the wind. If there is not enough rudder to compensate for the strong turning tendency caused by the steep bank, the wind is likely too strong for a safe landing on that particular runway with those wind conditions. This is the time to find an alternate runway.

Weathervaning, when the aircraft makes an uncommanded turn into the wind, is possible with strong crosswinds, especially in a tailwheel aircraft because of greater side area behind the main landing gear, which acts as a pivot point. The greater the crosswind component, the more difficult it is to prevent weathervaning.

Challenge to Find Crosswind Runways

Our aviation infrastructure is designed to mitigate crosswinds, as you will note runway orientation is usually into the prevailing winds. You show me an area with runways aligned 17/35, 18/36, or 1/19, and I’ll show you an area where the winds blow north-south. You may be lucky and fly out of an airport that was built in the 1940s when the runways were arranged in a triangle shape to accommodate the propeller-driven airplanes.

No matter how strong the winds, one of those runways had to work. Over the decades, most of these airports lost one if not two of the runways because the FAA determined they were not being used frequently, and the agency or airport sponsor did not want to pay for their upkeep. Some were turned into ramp space or taxiways—ensuring good crosswind technique is required.


This column first appeared in the November 2023/Issue 943 of FLYING’s print edition.

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Should You Add Flaps Mid-Takeoff on a Short Runway? https://www.flyingmag.com/should-you-add-flaps-mid-takeoff-on-a-short-runway/ https://www.flyingmag.com/should-you-add-flaps-mid-takeoff-on-a-short-runway/#comments Wed, 14 Dec 2022 18:48:51 +0000 https://www.flyingmag.com/?p=163506 A CFI says it’s best to fall back on the pilot's operating handbook.

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Question: When departing on a short runway—and since flaps produce drag—would it be wrong to wait until you have “enough” speed and then deploy flaps?

Answer:

The short answer is it would be wrong to add flaps during the takeoff roll for a normal short-field takeoff. Is that what the pilot’s operating handbook (POH) or aircraft flying manual (AFM) says to do? If the answer is no, then don’t do it. The procedures as published in the POH/AFM (flaps at a specific setting prior to the beginning of the departure roll, as well as VX and VY speeds) were established by the aircraft manufacturer for best results.

Please remember that flaps, when set to a percentage less than half of what is available, add more lift than drag—which is why the POH/AFM will indicate when they are appropriate for a short field takeoff. Adding flaps during the takeoff roll would likely be distracting and could be disastrous for many pilots.

Note the aircraft configuration when you consult the aircraft performance charts in the POH/AFM. Use the charts to determine the distance required for takeoff, and just to be safe, give yourself a distance margin of 50 percent, so for example if the chart indicates you will lift off in 1,023 feet, plan for 1,534 feet.

Position the aircraft on the runway allowing for use of every inch. This may mean the main wheels are on the pavement and the tail is over (or in) the weeds. Verify the aircraft is configured for a short field takeoff as indicated in the POH/AFM, meaning the appropriate flap setting. Standing on the brakes, bring the throttle up, adjusting mixture as needed for maximum power. Release the brakes. As the aircraft moves down the runway, note when the airspeed is “alive.” When rotation speed is achieved—and not before—lift off. Pitch for VX to clear obstacles. When you are safely above the obstacles, at a positive rate of climb, lower the nose to accelerate to VY, then raise the flaps incrementally to continue climbout at VY.

Do you have a question about aviation that’s been bugging you? Ask us anything you’ve ever wanted to know about aviation. Our experts in general aviation, flight training, aircraft, avionics, and more may attempt to answer your question in a future article.

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Why Are Flaps Used in Some Soft-field Takeoffs? https://www.flyingmag.com/why-are-flaps-used-in-some-soft-field-takeoffs/ Tue, 20 Sep 2022 12:49:15 +0000 https://www.flyingmag.com/?p=156214 Who said flaps don't increase lift? Flaps do increase lift. Reference Chapter 6 of the Pilot’s Handbook of Aeronautical Knowledge, which states, "Flaps are the most common high-lift devices used on aircraft. These surfaces, which are attached to the trailing edge of the wing, increase both lift and induced drag for any given angle of attack (AOA)."

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Question: If flaps don’t increase lift, then why is a small amount of flaps used in soft-field takeoffs for some aircraft?

Answer: Who said flaps don’t increase lift? Flaps do increase lift. Reference Chapter 6 of the Pilot’s Handbook of Aeronautical Knowledge, which states, “Flaps are the most common high-lift devices used on aircraft. These surfaces, which are attached to the trailing edge of the wing, increase both lift and induced drag for any given angle of attack (AOA).”

When flaps are deployed, they can lower the stall speed, which is why some aircraft manufacturers recommend the use of a minimal flap setting during a soft-field takeoff. The aircraft is able to lift off at a lower airspeed under positive control, and when the aircraft is off the ground and has enough flying speed the pilot retracts the flaps and continues the climb out at the appropriate V-speed.

Some aircraft do not require the use of flaps for takeoff unless it is a speciality takeoff—like a soft-field departure—and others require some flaps to be used on every takeoff; the amount is spelled out in the pilot’s operating handbook (POH) or aircraft flight manual (AFM).

Too much flap and the drag diminishes the usefulness of the lift—for example, if the POH calls for 10 degrees and the pilot mistakenly inputs 20 degrees, that airplane is going to eat up a lot of runway on the takeoff roll and the pilot may be fighting the elevator to get the airplane into the air—if liftoff happens at all. Before adding power, verify the required flap setting and the aircraft configuration, per the POH.

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