SL Helicopter Flying Handbook/Basic Flight Maneuvers

SECTION 8. Basic Flight Maneuvers

Figure 1: Cruise Flight

1 Cruise Flight

There are four fundamentals of flight upon which all maneuvers are based: straight-and-level flight, turns, climbs and descents. The initial goal of the student pilot should be to master these four fundamentals and be able to perform them based on an accurate feel and understanding of how the helicopter will perform.

Some general guidelines are as follows:

• Make control inputs slowly and smoothly. Abrupt control movements risk exceeding an aircraft limitation and departing controlled flight.
• Anticipate the effect of environmental conditions. The helicopter will not react the same way, or require the same control inputs at high altitude compared to sea-level.
• Understand the limitations and flight characteristics of the helicopter you are flying:
  • In left turns, there is increased torque, so more anti-torque (left pedal) will be required.
  • In right turns, there is decreased torque, so less anti-torque (right pedal) will be required.
  • Normal helicopter landings to a hover require increased helicopter power.
  • Always leave a way out if a maneuver must be aborted for some reason.

Figure 1 shows the basic control positions that should be used in cruise flight. The cyclic should be forward of center, with airspeed controlled by moving cyclic forward or aft. Turns are made primarily with left/right cyclic. Finally, collective is adjusted to achieve a zero vertical speed.

Figure 2: Turn Coordinator

1.1 Straight-and-Level Flight

Figure 3: Yaw String

In straight-and-level cruise flight, the goal should be to fly a constant heading at a constant speed without gaining or losing altitude. In addition, the aircraft should be horizontally level and well coordinated. Use collective to control altitude using the VSI (Vertical Speed Indicator) as reference. If a descent or climb is indicated, increase or decrease collective to maintain altitude. Airspeed is controlled with the forward and backwards cyclic. Move the cyclic forward to increase airspeed, and ease back on the cyclic to reduce airspeed. Meanwhile, heading control is maintained with left and right cyclic. Use left/right cyclic opposite to any drift either by reference to the heading indicator, or the horizon to keep the helicopter level and on course.

The pedals are used to maintain coordination. This is normally done with the turn coordinator (Figure 2), but some aircraft may use a yaw string Figure 3. Coordination using the turn coordinator is performed with reference to the black ball, usually at the bottom of the instrument. When the black ball is deflected to the inside of the turn (e.g., the ball is deflected right of center in a right turn), this is called a slip. When the black ball is deflected to the outside of the turn (e.g., the ball is deflected left of center in a right turn), this is called a skid. Pedal should be applied on the side to which the ball moves. Think "step on the ball".

Common Errors

1. Failure to maintain coordinate flight
2. Failure to maintain target airspeed
3. Failure to hold a specific ground track

1.2 Turns

Turns should be made primarily with the cyclic, using the pedals to maintain coordination. Turns are made by deflecting a portion of the thrust vector toward the direction of turn. For this reason, it may be necessary to increase collective to maintain altitude in a turn. In a turn with a 60 degree bank, the amount of thrust needed to maintain altitude is twice that needed to maintain altitude in level flight. In normal operations turns should be limited to 30 degrees of bank. As in straight-and-level flight, the pilot should use the turn coordinator or yaw string to maintain coordination.

Common Errors

1. Failure to maintain altitude and airspeed
2. Using too little or not enough anti-torque pedal

1.3 Normal Climbs

To enter a climb at constant airspeed, the pilot should simultaneously increase collective and throttle, then adjust pedals as necessary to maintain coordination. Since an increase in collective will also increase the horizontal component of lift, the cyclic must also be moved aft slightly, or airspeed will increase. Remember that unlike in an airplane, the attitude of a helicopter does not change significantly in a climb vs. straight-and-level flight.

If the pilot wishes to climb with decreased airspeed, then a climb can be initiated with aft cyclic. This will reduce the horizontal component of total thrust and redirect it downward, thus resulting in a a climb.

To level off from a climb, gradually reduce the collective, and apply a small amount of forward cyclic to maintain airspeed. You should lead your level-off by approximately 10% of your climb rate. For example if climbing at 500 feet/min, begin your level-off 50 feet before your target altitude.

Common Errors

1. Failure to maintain power for target airspeed
2. Failure to adjust anti-torque as the power applied changes
3. Leveling off too soon or too late

1.4 Normal Descents

To enter a descent at constant airspeed, the pilot should simultaneously decrease collective and throttle, then adjust pedals as necessary to maintain coordination. Since an decrease in collective will also decrease the horizontal component of lift, the cyclic must also be moved slightly forward, or airspeed will decrease.

To level off from a descent , gradually raise the collective, and apply a small amount of aft cyclic to maintain airspeed. You should lead your level-off by approximately 10% of your descent rate. For example if descending at 500 feet/min, begin your level-off 50 feet before your target altitude.

Common Errors

1. Failure to maintain power for target airspeed
2. Failure to adjust anti-torque as the power applied changes
3. Leveling off too soon or too late

2 Hovering

Figure 4: Pick-up to Hover

There are two types of hovering. In Ground Effect (IGE) hovering occurs in ground effect within a few meters of a surface (land, water, or a flat prim) and Out of Ground Effect (OGE) hovering occurs at altitude away from any surface. While hovering in general requires more power (collective) than other phases of flight, OGE hovering requires significantly more power than IGE hovering, and may be impossible depending on how heavily loaded the helicopter is. Cyclic inputs in a hover should be small and controlled taking into account delay between input and the reaction of the helicopter. Use collective to control hight. It is important to learn to anticipate the reaction of the helicopter in response to an input. Over-controlling is a common problem for the beginning helicopter pilot. Forward hover taxi is performed by a very slight forward positioning of the cyclic. In general all hover taxiing should be performed with no more than a dot-width of movement from the center on the cyclic control display.

2.1 Vertical Takeoff to a Hover

Picking up to a hover is performed by slowly raising the collective until the helicopter becomes light on the skids (Figure 4). Pedal should be applied to stop any rotation, and cyclic should be applied to stop any lateral or forward/back motion. Considerable left pedal may be required in the pick-up to counteract torque from the main rotor. The goal should be to bring the helicopter up vertically without any rotation or translation.

Common Errors

1. Failing to ascend vertically as the helicopter picks up
2. Picking up too quickly
3. Failing to maintain heading

2.2 Stationary Hover

Figure 5: Hovering

The goal in a stationary hover is to maintain a fixed position in three dimensions (Figure 5). The pilot should maintain a constant hover height, heading and position over the ground. Maintaining a stationary hover is one of the most difficult tasks for a new helicopter pilot to learn, yet at the same time is fundamental to almost all other skills. This is because a pilot must make constant control adjustments to keep the helicopter

Common Errors

1. Failure to maintain constant hover height
2. Failure to maintain a fixed position
3. Failure to maintain a fixed heading
4. Overcontrolling and succumbing to pendular action

2.3 Set Down from a Hover

Setting down from a hover essentially the reverse of a pickup. Slowly lower collective letting helicopter settle. As collective is lowed, right pedal may be necessary due to the reduction in torque.

Common Errors

1. Failing to descend vertically
2. Setting down too quickly
3. Failing to maintain heading

2.4 Hovering Turn

A hovering turn is a turn performed in a hover at zero or low speed in which the helicopter rotates either left or right. To initiate a hovering turn, apply pedal in the direction of turn desired. Use cyclic to maintain a constant position and collective to maintain a constant hover height. When possible, turns to the left should be favored over right turns to avoid the possibility of LTE (Loss of Tail Rotor Effectiveness) if the rate of turn in the direction of torque is allowed to develop too far.

Common Errors

1. Failing to maintain slow, constant rate of turn
2. Failing to maintain constant position
3. Failing to maintain constant hover height

2.5 Forward Hovering Flight

Forward hovering is usually used to move the helicopter to a specific location. From a hover, apply gentle forward cyclic to begin moving. Once in motion, it may be necessary to apply some aft cyclic to prevent the helicopter from moving too fast. Speed should be limited to a brisk walking speed to keep the helicopter below ETL during a forward hover.

To stop the forward hover, apply aft cyclic until the helicopter stops. As the motion stops, return the cyclic to the neutral position.

Common Errors

1. Failure to maintain constant heading aligned with direction of movement
2. Failure to maintain constant speed
3. Failure to maintain constant hover height

2.6 Sideward Hovering Flight

Sideward flight is sometimes necessary when conditions make forward flight impossible. A constant airspeed and heading should be made while performing the maneuver. Before beginning the maneuver, be sure to clear the area for obstacles and personnel. While in motion, be particularly cautious about ensuring adequate height above the ground to avoid catching a skid and entering dynamic rollover.

To begin the maneuver, start by applying sideways cyclic. Increase collective as necessary to maintain a constant altitude, and use pedal to maintain heading. Anticipate a small amount of left pedal if collective was increase. To exit the maneuver, return the cyclic to neutral and adjust collective and pedals as necessary.

Common Errors

1. Failure to clear area prior to maneuver
2. Failure to maintain constant speed
3. Failure to maintain constant hover height
4. Failure to maintain heading perpendicular to direction of travel

3 Taxiing

Taxiing is the movement of the helicopter on taxiways or other prescribed routes. There are three different types of taxiing that can be one in helicopters. These will be described in the following sections.

3.1 Hover Taxi

A hover taxi is a slow movement of the helicopter along route at less than 25 feet above the ground. The techniques are the fundamentally the same as forward hovering with pedal turns to turn.

3.2 Air Taxi

An air taxi is used to move quickly from one point to another on an airport. Begin an air taxi like a normal takeoff, but lower collective slightly to maintain a height of 10 to 20 meters over the airport while pitching with cyclic for approximately 50 mph. To exit an air taxi and land, apply back cyclic, down collective and ride pedal as necessary. Then make a normal landing to hover.

Common Errors

1. Failure to maintain proper airspeed
2. Failure to maintain desired altitude
3. Failure to maintain desired heading and ground track
4. Overflying parked aircraft and vehicles

3.3 Surface Taxi

Surface taxi normally applies to aircraft with wheels, and can be used when reducing the amount of rotor downwash is a goal. To perform a surface taxi, apply forward cyclic about halfway forward from neutral, and slight upward collective, but not enough to lift to a hover. Once moving, you may need to reduce collective a bit to prevent developing excess speed. Once established in a surface taxi, use collective to control speed, and the pedals to turn.

Common Errors

1. Improper use of cyclic
2. Failure to use pedals to steer
3. Failure to use collective to control speed

4 Takeoffs

4.1 Normal Takeoffs from a Hover

Figure 6: Normal Take-Off

Normal takeoffs should begin in a hover with an adequate obstacle free area ahead of the helicopter. From a hover, apply forward cyclic and allow helicopter to accelerate forward in ground effect. At about 30 mph, the helicopter will achieve ETL (Effective Translational Lift) allowing the helicopter to climb (see Section 8 for details on ETL). Some brief aft cyclic at 40 mph may be necessary. Control airspeed with forward cyclic to maintain a best climb airspeed of about 50 mph. Applying too much forward cyclic will reduce climb performance. Raise collective to increase rate of climb, but do not exceed the maximum manifold pressure of 29 inches (red line).

Common Errors

1. Failure to use sufficient collective to prevent loss of altitude before achieving ETL
2. Using too much collective before ETL causing the helicopter to balloon
3. Pitching down too aggressively
4. Failing to maintain a straight flight path
5. Failing to maintain proper airspeed during climb
6. Failing to maintain proper ground track in climb-out

4.2 Takeoffs from the Surface

Takeoffs from the surface can be used to move the helicopter from a position on the ground into ETL and then normal flight with the minimum amount of power. This technique might be used if the helicopter where heavily loaded, or for a high density altitude departure.

Begin with the collective full down. Slowly raise the collective until the helicopter is light on the skids and adjust cyclic and pedals as necessary to maintain heading and avoid drift. Continue to raise collective and apply forward cyclic as soon as the helicopter leave the ground. Continue to accelerate until the helicopter passes through ETL then climb out as normal.

Common Errors

1. Departing the surface with too aggressive nose down attitude
2. Using collective too aggressively resulting in a vertical climb
3. Failing to maintain heading during the maneuver

5 Ground Reference Maneuvers

Ground reference maneuvers are used a training exercise to help a pilot develop the skill to divert attention between the operating the aircraft while maintaining a specific path on the ground and simultaneously watching for other aircraft.

5.1 Rectangular Courses

Figure 7: Rectangular Course

The rectangular course is a training maneuver in which the helicopter flies a specific ground track (see Figure 7). Specific ground reference points should be selected at each corner of a rectangular course. The maneuver should be entered at a 45 degree angle on the entry leg. The pilot should maintain a constant altitude and airspeed throughout the maneuver. If the student is having difficulties maintain a track, try flying the course at a lower altitude. For best results, the pilot should choose reference points that are just inside the path flown to make it easier to maintain visual contact.

Common Errors

1. Faulty entry technique
2. Poor planning, orientation or diversion of attention
3. Uncoordinated flight
4. Failure to maintain selected altitude and airspeed
5. Selection of ground reference point without suitable emergency landing site
6. Not flying a course with squared legs
7. Failure to lead turns resulting in overshooting the next track

5.2 S-Turns

Figure 8: S-Turns

S-turns are another training maneuver to help pilots develop the skill to maneuver the helicopter along a specific path. The S-turn requires both left and right turns. The maneuver consists of approaching a straight feature on the ground (road, rail road track, etc) at a 90 degree angle, then making two have circles crossing the road as shown in Figure 8. The first half-circle turn should begin simultaneous with crossing the reference line. The first 180 degree turn should end just as the aircraft crosses the reference line again, then the pilot should immediately begin a 180 degree turn in the opposite direction. Like the first turn, the end of the second 180 degree turn should end just as the aircraft crosses the reference line for a third time. Over the course of the maneuver, the pilot should maintain a constant airspeed and altitude. Both the left and right turns should have the same radius.

Common Errors

1. Using pedal to "force" a turn
2. Slipping or skidding in the turn
3. Unsymetrical turns during the maneuver
4. Failure to hold a selected altitude or airspeed
5. Excessive bank angle

5.3 Turns Around a Point

This is another training maneuver in which the objective is to maintain a constant radius turn around a selected ground feature. The pilot should maintain constant airspeed and altitude throughout the maneuver. In addition to being a training maneuver, this maneuver forms the basis of high reconnaissance, for off-airport landings. The maneuver should be entered tangent to the circle with the turn beginning as the reference point is at 90 degrees to the aircraft heading. This maneuver should be practiced with both left and right turns.

Common Errors

1. Faulty entry
2. Poor planning and diversion of attention
3. Uncoodtinate flight
4. Failure to maintain selected airspeed and altitude
5. Failure to maintain constant distance from reference point
6. Excessive bank angle

5.4 Traffic Patterns

Figure 9: Traffic Pattern

A traffic pattern is essentially a rectangular course with a runway along one of the legs and incorporating a take-off and landing. In addition, each of the legs has a specific name (see Figure 9). The names of the legs can help pilots communicate their position relative to the airport, and encourages standard practice when making approaches and landings. Traffic patterns are identified by the direction of turn. A traffic pattern with all left turns (as in Figure 9) is called 'left traffic', while a traffic pattern with right turns is called 'right traffic'.

The initial leg after take-off is called the upwind leg. This is where the initial climb-out occurs, and the pilot should reach a safe altitude before turning. The next legs are the crosswind, downwind and base legs. The pilot should attempt to keep each turn at 90 degrees, and keep the crosswind leg perpendicular to the extended runway centerline, and the downwind parallel to the runway. The final turn is called, surprisingly, "final". This is the final descent to landing which should be performed with a stabilized airspeed and descent rate.

Entry to the traffic pattern depends on the direction from which the pilot approaches, and any potential hazards and obstacles around the airport. The most common entries are to enter on the downwind or base, though a direct entry to final can sometimes be appropriate when coming from that direction.

Common Errors

1. Faulty entry technique
2. Poor planning, orientation or diversion of attention
3. Uncoordinated flight
4. Failure to maintain selected altitude and airspeed
5. Not flying a course with squared legs
6. Failure to lead turns resulting in overshooting the next track
7. Failure to clear for other traffic

6 Landings

Figure 10: Normal Approach to Landing

6.1 Normal Landing to a Hover

Begin a normal landing (see Figure 10) by reducing air speed to bout 50 mph and lowering the collective to maintain an approximately 500 foot per minute descent. Choose a target spot for your landing, keeping that spot at approximately the same place on the window. As you approach your touchdown spot, slowly decrease airspeed with back cyclic, and descent rate with up collective. Maintain above 30 mph until just before touchdown to avoid vortex ring state. As you transition to a hover, you will need additional up collective and left pedal to compensate for the torque.

Common Errors

1. Failing to maintain proper RPM through the approach
2. Improper use of collective in controlling the rate of descent
3. Failure to use pedals appropriately to maintain coordinated flight
4. Failure to maintain constant airspeed
5. Failure to maintain proper ground track

6.2 Landings to the Surface

When landing at an airport at high-density altitude, or if full power is not available due to an equipment failure, there may not be enough power to hover once coming out of ETL. In these cases, it may be necessary to conduct a landing directly to the surface.