Mastering the Art of Sling Loading: Insider Tips for the Inward Phase

Table of Contents

• Introduction
• The Root Phase: Definition and Importance
• Transitioning to and from the Inward Phase
• Managing the Load During the Inward Phase
• Mapping the Route Before Each Mission
• Speed Management in the Inward Phase
• Determining Optimal Airspeed for Different Loads
• Understanding Load Oscillation and Spinning
• Importance of Gradually Increasing Airspeed
• Factors Affecting Load Stability
• The Art of Slowing Down for the Approach
• Setting Parameters for a Controlled Descent
• Using Peripheral Vision for Airspeed Assessment
• Escape Routes and Stopping the Load in Hover
• Stabilizing Spinning Loads During Delivery
• Considerations for Empty Hook Return
• Safety Precautions and Avoiding Accidents

The Art of Sling Loading: Mastering the Inward Phase

Sling loading, a technique commonly used in aerial operations, involves transporting objects using an external sling attachment from a helicopter. In this tutorial, we will dive deep into the inward phase of sling loading, exploring its importance, nuances, and best practices. The ability to maneuver a load safely and efficiently during this phase is crucial for successful operations. So let's strap in and uncover the secrets of mastering the inward phase of sling loading.

Introduction

Sling loading is an essential skill for helicopter pilots involved in tasks such as lifting heavy cargo, conducting search and rescue missions, or executing construction projects. The inward phase, also known as the root phase, is a critical part of the sling loading process that requires careful attention and adherence to safety procedures. In this article, we will explore the various aspects of the inward phase and provide valuable insights into managing the load, determining optimal airspeed, and ensuring a controlled descent during the approach.

The Root Phase: Definition and Importance

Before diving into the intricacies of the inward phase, let's first understand its definition and significance. The root phase refers to the period after the load has been picked up and before the approach and delivery of the load. It serves as a transitional stage where the pilot must maintain stability and control over the load while ensuring the safety of personnel and property on the ground. By establishing a clear set of rules and following proper procedures, pilots can effectively navigate through the root phase and set the stage for a successful delivery.

Transitioning to and from the Inward Phase

To ensure a seamless transition between phases, it is essential to plan the route before each sling loading mission. Mapping out the flight path allows for better navigation and minimizes the risk of encountering obstacles or hazardous conditions. By choosing a safe route, pilots can focus on managing the load and maintaining optimal airspeed during the inward phase. This preparatory step lays the foundation for a smooth and controlled operation.

Managing the Load During the Inward Phase

One of the key aspects of the inward phase is speed management. The flight manual provides guidelines regarding the maximum airspeed at which an underslung load can be flown. For instance, the H125 helicopter has a maximum airspeed limit of 80 knots. However, it is important to understand that not every load can be flown at this limit. The VNE (Velocity Never Exceed) of the load, which refers to the airspeed at which the load starts oscillating or spinning uncontrollably, varies for different load types.

Determining the optimal airspeed for a particular load involves careful observation and incremental adjustments. By gradually increasing the airspeed in stages and monitoring the load's behavior, pilots can find the speed at which the load remains stable. This approach of incremental acceleration applies to each new type of load, ensuring safe operations and avoiding load instability during flight.

During the inward phase, it is crucial to be cautious and attentive to the load's movements. Different loads exhibit distinct aerodynamic characteristics, and being able to anticipate their behavior is vital for maintaining control. Larger and lighter loads often produce substantial drag, necessitating slower flying speeds. On the other hand, compact and high-density loads, such as bags or concrete buckets, can generally be flown at the flight manual's maximum limit of 80 knots.

Understanding Load Oscillation and Spinning

Load oscillation and spinning can pose significant challenges during the inward phase of sling loading. Oscillation refers to the side-to-side motion of the load, while spinning involves the load rotating around its axis. These undesirable effects can occur when the load reaches its VNE or when airflow interacts with the load in unbalanced ways.

By slowing down to a near-hover or reducing airspeed when load oscillation or spinning occurs, pilots can stabilize the load or minimize the oscillations to a manageable level. If necessary, gently lowering the load onto a stable surface, such as a tree or the ground, can help counteract the spinning motion and allow for safe handling by ground crew members. It is essential to prioritize the safety of personnel and avoid placing them at risk due to uncontrolled load movements.

Importance of Gradually Increasing Airspeed

As mentioned earlier, incremental acceleration plays a significant role in sling loading operations. Gradually increasing the airspeed in stages allows pilots to assess the load's behavior and determine the optimal speed for safe flight. This approach prevents sudden load disturbances and gives pilots the opportunity to identify any potential instability issues before reaching critical speeds.

By adopting a cautious and systematic approach to accelerating the airspeed, pilots can maintain better control over the load and navigate through the inward phase with confidence. This method also provides insights into load-specific aerodynamic characteristics, empowering pilots to make informed decisions regarding speed adjustments for various load types.

Factors Affecting Load Stability

Several factors can impact the stability of a load during the inward phase. The shape and size of the load, the weight distribution, and environmental conditions all contribute to how the load behaves in flight. Big and light loads tend to generate more drag, requiring slower flying speeds to maintain stability. On the other hand, compact and high-density loads offer better aerodynamic stability and can be flown closer to the flight manual's recommended limit.

Additionally, pilots should keep in mind that load behavior may change during the delivery phase as well. The downwash from the helicopter's rotor can induce spinning or oscillations in the load when slowing down for the approach. Therefore, maintaining situational awareness and adjusting the airspeed or handling techniques accordingly are crucial for safe and successful deliveries.

The Art of Slowing Down for the Approach

As the inward phase nears its conclusion, pilots must prepare to transition into the approach phase. Slowing down the helicopter at the right moment is essential for a smooth and controlled descent. By aiming for a specific point in space based on lateral position and altitude, pilots can ensure a well-calibrated approach that minimizes excessive horizontal movement and facilitates a controlled vertical descent.

Determining the appropriate point for initiating the approach involves considering factors such as lateral position, altitude, and the presence of obstacles or safe escape routes. By maintaining a consistent descent profile and adhering to predetermined parameters, pilots can effectively manage the load's descent and be ready to make any necessary adjustments or go-arounds if required.

Setting Parameters for a Controlled Descent

To achieve a controlled descent during the approach, it is crucial to set parameters that align with the desired flight profile. These parameters include airspeed, altitude, and lateral positioning. Aiming for a specific airspeed that allows for a stable and comfortable approach is important. The airspeed should not be too fast, as it may compromise the pilot's ability to abort the approach if needed.

When flying at speeds below 40 knots, the airspeed indicator may become less reliable. In such cases, relying on a combination of feeling and peripheral vision can provide valuable information about the helicopter's speed. Monitoring the load's appearance through the sling window and ensuring it resembles a walking pace can assist in determining an appropriate speed for the approach.

Escape Routes and Stopping the Load in Hover

Safety should always be a top priority during sling loading operations. Pilots must be aware of escape routes and have contingency plans in place throughout the inward phase and the subsequent approach. Maintaining situational awareness and being ready to go around or stop the approach in case of an emergency is crucial for the well-being of personnel and the preservation of property.

Choosing a starting point for the approach that allows for a safe escape route, free from obstacles or potential hazards, provides pilots with the flexibility to react quickly to any unforeseen circumstances. By keeping sufficient distance from the delivery area, pilots can mitigate risks and ensure a secure operation.

In certain situations, it may be necessary to stop the load in hover during the inward phase or approach. Pilots should be prepared to halt the descent and maintain a stable hover if required. This maneuver allows for a controlled and safe operation, preventing any accidental load contact with the ground or personnel.

Stabilizing Spinning Loads During Delivery

During the delivery phase, load spinning may become an issue as the load interacts with the helicopter's downwash. If load oscillation or spinning persists even after slowing down for the approach, pilots must stabilize the load before ground crew members can safely handle it. This can be accomplished by gently lowering the load onto a stable surface, such as a tree or the ground, to reduce or eliminate the spinning motion.

Ideally, this stabilization procedure should be performed closer to the delivery area, preferably on or near the final approach path. Doing so minimizes the chances of load spinning up again before it reaches the desired location. Prioritizing the safety of ground crew members and ensuring they have a stable load to work with is essential for successful sling loading operations.

Considerations for Empty Hook Return

Once the delivery is complete, the pilot must return to the load master with an empty hook. Even during this seemingly straightforward task, certain considerations must be taken into account. If using a fiber long line, turbulent and bumpy conditions can pose a risk of the long line hitting the tail rotor. Therefore, maintaining an appropriate airspeed and exercising caution is crucial.

Starting slowly and gradually increasing the airspeed in stages allows pilots to assess the behavior of the line and hook. By observing any potential disturbances or instability, pilots can make adjustments to ensure a safe return to the load master. Vigilance and careful control remain necessary even during seemingly routine maneuvers.

Safety Precautions and Avoiding Accidents

Throughout the inward phase of sling loading operations, pilots must prioritize safety and adhere to established procedures. It is critical not to fly over people or objects on the ground that could be harmed in the event of an accident or load release. By following recommended speed limits, incrementally accelerating the airspeed, and attentively managing load stability, pilots can mitigate risks and ensure the safety of all individuals involved in the operation.

Each new type of load presents unique challenges and requires a gradual acceleration approach to determine the optimal airspeed for safe flight. By adopting a systematic and cautious mindset, pilots can mitigate potential instability issues and make informed decisions during the inward phase. Effective communication with ground crew members and continuous situational awareness contribute to the overall success of sling loading operations.

Conclusion

Mastering the inward phase of sling loading is a skill that requires a combination of technical knowledge and practical experience. By understanding the nuances of speed management, load stability, and controlled descent, helicopter pilots can execute sling loading operations with precision and safety. Adhering to established procedures, being vigilant about load behavior, and prioritizing the well-being of personnel and property are the cornerstones of successful inward phase management. So, as you embark on your next sling loading mission, remember the art of the inward phase and soar with confidence!