Master the Inward Phase of Sling Loading: Speed Management and Load Safety
Table of Contents
- Introduction
- Definition of Terms
- The Root Phase
- Definition and Purpose
- Rules and Safety Measures
- Choosing a Safe Route
- Managing the Load in the Inward Phase
- Speed Management
- Determining the Maximum Airspeed
- Types of Loads and Recommended Speeds
- Big and Light Loads
- Compact and High-Density Loads
- Recognizing the VNE of the Load
- Identifying Load Oscillation and Spinning
- Effects of Airspeed Increase
- Transitioning to the Approach Phase
- Establishing Speed and Altitude Parameters
- Smooth and Controlled Descent
- Escaping or Stopping the Approach
- Stabilizing Spinning and Oscillating Loads
- Slowing Down to Near Hover
- Lowering the Load for Ground Crew
- After Delivery Considerations
- Handling Empty Hook and Long Line Safety
- Incremental Acceleration and Load Behavior
🚁 Sling Loading Tutorial: Managing the Inward Phase
In the world of helicopter operations, sling loading is an essential technique that allows for the transportation of heavy loads through the use of an attached sling. However, the success of a sling loading operation depends greatly on the careful management of different phases involved. In this article, we will dive deep into the inward phase of sling loading and explore various aspects related to speed management, load behavior, and safety measures. So, let's buckle up and get ready to navigate through the intricacies of the inward phase!
1. Introduction
As a precursor to understanding the inward phase, it's crucial to have a solid grasp on the overall concept of sling loading. Sling loading is the process of lifting and transporting external objects suspended beneath a helicopter. This technique finds extensive usage in industries such as construction, logging, firefighting, and even military operations. The inward phase, specifically, refers to the period after the load has been picked up and before the approach and delivery of the load.
2. Definition of Terms
Before delving deeper into the inward phase, let's establish clarity by defining some key terms. These terms will act as our guiding compass throughout this article.
2.1 The Root Phase
The root phase is the initial segment of sling loading where the load is securely picked up and stabilized. It serves as a transitional phase between the lift-off and the inward phase. During the root phase, it's essential to ensure the load remains under control and does not pose a risk to people or property on the ground.
3. The Root Phase: Rules and Safety Measures
The opening stages of the inward phase demand strict adherence to a set of rules and safety measures to establish a safe framework for the entire operation. After mapping out the chosen route to be flown, some essential guidelines must be followed.
Firstly, it's crucial to prioritize speed management during the inward phase. The flight manual provides specific airspeed limitations for flying with an underslung load. For instance, the maximum airspeed for the H125 helicopter is set at 80 knots. However, it's important to note that not all loads can be flown at this maximum speed.
To determine the appropriate speed for a specific load, it's recommended to gradually increase the airspeed while closely monitoring the load's behavior. Begin by flying the load at around 30 knots and observe its stability. If it shows no signs of instability, increase the speed to 40 knots and assess again. Continue this incremental process until a safe and suitable speed is determined for each type of load.
It's worth noting that various load shapes and sizes can significantly impact their drag and, thus, their ideal flying speed. Large and lightweight loads tend to generate a substantial amount of drag, necessitating slower speeds. On the other hand, compact and high-density loads, such as big bags or concrete buckets, can typically be flown at the maximum speed allowed by the flight manual.
4. Types of Loads and Recommended Speeds
When it comes to sling loading, loads come in various shapes and sizes, each with its own characteristics and behavior. Understanding these load types is crucial in determining the appropriate speed at which they can be safely flown.
4.1 Big and Light Loads
Loads that are both big and light pose a unique challenge during sling loading operations. Due to their size and low density, these loads tend to produce significant drag, making them more prone to instability when subjected to higher speeds. Therefore, it's crucial to fly these loads slowly and exercise caution to ensure a safe and controlled operation.
4.2 Compact and High-Density Loads
In contrast to big and light loads, compact and high-density loads have denser structures. This characteristic allows them to tolerate higher speeds without compromising stability and safety. Examples of such loads include large bags or fully loaded concrete buckets, which can generally be flown at the maximum airspeed limits specified in the flight manual.
5. Recognizing the VNE of the Load
To ensure the safety and stability of the sling-loaded load, it's crucial to be able to recognize the VNE (Velocity Never Exceed) point. This refers to the airspeed at which the load starts oscillating or spinning uncontrollably. Identifying this critical airspeed becomes pivotal in maintaining control during the inward phase.
Upon exceeding the VNE of the load, rotation and oscillations begin to increase rapidly, posing a significant risk to the operation. Therefore, it's essential to closely monitor the load's behavior as the airspeed increases. By gradually increasing the speed, it becomes easier to identify the threshold at which oscillations and rotations become prevalent.
Let's take a closer look at two scenarios that depict the effects of reaching the VNE of the load.
5.1 Load Oscillation and Spinning
In one scenario, as the airspeed increases beyond a certain point, the load starts rotating and oscillating under the downwash of the helicopter. Continuing to accelerate the airspeed would only intensify the spinning and oscillations, rendering the situation potentially dangerous.
However, in the second scenario, the load initially appears almost identical to the previous one. Yet, upon reaching a slightly higher speed, rotation spontaneously ceases. This indicates that the load, in this case, can tolerate higher speeds without significant instability.
It's important to note that the behavior of the load during delivery must also be taken into account. Sometimes, the load may start spinning again under the downwash as the helicopter decelerates during the transition to the approach phase. In such cases, it becomes crucial to stabilize the load before ground crews can safely handle it.
6. Transitioning to the Approach Phase
After successfully managing the inward phase, the next crucial step in the sling loading operation is transitioning smoothly into the approach phase. This phase involves establishing precise speed and altitude parameters to ensure a controlled descent and a safe approach to the delivery area.
To determine the ideal speed and altitude for the approach, it's important to identify a specific point in space from where these parameters can be managed effectively. This point should be located at a sufficient distance from the delivery area, allowing for easy decision-making in case of any unforeseen problems or the need for a go-around.
Altitude can be determined using the altimeter, aiming for a point that allows for a controlled descent without excessive horizontal movement. This minimizes the need to maneuver the load extensively during the approach, providing a smoother and more stable descent.
When it comes to speed during the approach phase, it's crucial to choose a comfortable airspeed while keeping it below the limit that would hinder the ability to abort the approach if necessary. When flying at speeds slower than 40 knots, the airspeed indicator's reliability diminishes. Therefore, the preferred method becomes relying on a personal feel for the speed. Alternatively, ground speed from the GPS can be used as a reference, keeping in mind that it's not a direct indication of airspeed.
7. Stabilizing Spinning and Oscillating Loads
Despite careful planning and management, there may be instances where the load starts spinning or oscillating excessively during the inward phase. In such cases, prompt action must be taken to stabilize the load and ensure the safety of both personnel and property on the ground.
Slowing down to a near-hover can often provide the needed stability by reducing oscillations and minimizing spinning. However, if the load remains unstable due to its weight and momentum, and ground crew members need to handle the load before it can touch the ground, it becomes necessary to stop the oscillations and spinning. This can be achieved by gently lowering the load onto a stable surface, such as a tree or the ground. Ideally, this should be done closer to the delivery area, reducing the chances of the load restarting its oscillations before reaching the designated location.
8. After Delivery Considerations
Once the delivery is complete, and the helicopter returns to the load master with an empty hook, certain factors need to be taken into consideration to ensure a safe retrieval process. Long lines, particularly those made of fibers, can pose a risk if not handled with care. In turbulent and bumpy conditions, descending rapidly at high speeds can cause the long line to hit the tail rotor, potentially leading to dangerous situations. Therefore, it's essential to maintain a suitable airspeed and gradually increase it while observing the behavior of the line and hook.
It's worth mentioning that operating at the flight manual's maximum airspeed of 80 knots is not necessary in order for the long line to become a potential hazard. By starting slowly and incrementally increasing the airspeed while monitoring load behavior, the risks associated with retrieval can be mitigated effectively.
9. Conclusion
Sling loading, particularly during the inward phase, requires careful attention to detail and adherence to specified safety measures. This article has highlighted the importance of speed management, load behavior assessment, and various safety considerations during sling loading operations. By following the guidelines discussed and approaching each new load with caution and attentiveness, helicopter pilots can ensure the successful and secure transport of external loads.
Remember, safety is paramount at all times. Never overfly areas inhabited by people or objects that could be harmed should the load be dropped or lost. The inward phase should be approached with a gradual increase in speed, continuously monitoring load behavior to identify the VNE, and making necessary adjustments to maintain control. Fly responsibly and confidently, keeping the skies secure for all.
Highlights:
- The inward phase of sling loading involves managing the load between the pickup and delivery phases.
- Speed management is crucial during the inward phase, and load behavior should be closely monitored to ensure stability.
- Different load types require varying speeds for safe flight, with big and light loads necessitating slower speeds.
- Recognizing the VNE of the load is essential to maintain control and prevent dangerous oscillations and spinning.
- Transitioning from the inward phase to the approach phase requires precise speed and altitude parameters for a controlled descent.
- Stabilizing spinning and oscillating loads can be achieved by slowing down or gently lowering the load onto a stable surface.
- Careful consideration should be given to the airspeed during the retrieval process to avoid hazards associated with long lines.
FAQ
Q: Can I fly all loads at the maximum airspeed mentioned in the flight manual?
A: No, speed management for sling loads depends on the size, weight, and density of the load. Each load type has specific requirements for safe flight.
Q: How do I determine the VNE of a load?
A: The VNE of a load can be identified by gradually increasing the airspeed during the inward phase while observing the load's behavior. Any signs of excessive oscillation or spinning indicate that the VNE has been reached or exceeded.
Q: What are the safety considerations when transitioning to the approach phase?
A: Establishing precise speed and altitude parameters is essential. The speed should be comfortable and allow for aborting the approach if needed, while the altitude should ensure a controlled descent with minimal horizontal movement.
Q: How can I stabilize spinning and oscillating loads during the inward phase?
A: Slowing down to a near-hover can often help stabilize the load. If that is not sufficient, gently lowering the load onto a stable surface, such as a tree or the ground, can stop the oscillations.
Q: Why is it important to consider airspeed when retrieving the hook?
A: Rapid descents at high speeds can pose a risk to long lines, particularly in turbulent conditions. Gradually increasing airspeed and monitoring load behavior ensures safe retrieval without endangering the helicopter or personnel on the ground.
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