In the world of aviation, there are many terms and abbreviations that are used to describe various aspects of flight. One such term is “hold,” which is abbreviated as HLD in aviation jargon. A hold refers to a specified location or pattern in the sky where an aircraft is required to stay for a certain period of time. This can be due to various reasons such as congestion at the destination airport, weather conditions, or air traffic control instructions.
Understanding the concept of a hold is essential for pilots and air traffic controllers alike, as it plays a crucial role in maintaining safe and efficient air traffic flow. Let’s take a closer look at the different aspects of holds in aviation.
Contents
Types of Holds in Aviation
Holds can be categorized into two main types: standard holds and non-standard holds. Standard holds are predefined patterns that are established based on specific criteria and are widely used in aviation. Non-standard holds, on the other hand, are temporary holds that are created on an ad-hoc basis to accommodate a specific situation.
1. Standard Holds
Standard holds are established at specific navigational aids such as VOR (VHF Omni-directional Range) or DME (Distance Measuring Equipment) stations. They are depicted on aviation charts and are designed to be flown using specific inbound and outbound tracks, as well as predefined turn directions.
In a standard hold, the aircraft enters the hold by performing a procedure turn or a direct entry. In a procedure turn, the aircraft flies outbound on the inbound track, performs a standard rate turn of 180 degrees, and then flies inbound on the outbound track to join the holding pattern. A direct entry involves flying directly to a point in the holding pattern without performing a procedure turn.
The entry procedure and turn direction for a standard hold are determined by the holding pattern’s position relative to the aircraft’s course. If the holding pattern is on the aircraft’s course, a parallel entry with a right-hand turn is typically used. If the holding pattern is on the non-course side, a teardrop entry with a left-hand turn or a direct entry may be employed.
2. Non-Standard Holds
Non-standard holds, as the name suggests, deviate from the established standard procedures and are less common than standard holds. They are typically created to accommodate unique situations or constraints that cannot be addressed using the standard holding patterns.
Non-standard holds can be established using specific GPS waypoints or geographical references. These holds may not be depicted on aviation charts and often require coordination between the pilot and air traffic control for effective execution.
Examples of situations that may require non-standard holds include temporary airspace restrictions, holding for coordination with other traffic, or holding at a specific location to meet altitude restrictions.
Key Elements of a Standard Holding Pattern
A standard holding pattern consists of several key elements that are designed to ensure safe and efficient air traffic flow. These elements include:
1. Holding Fix
A holding fix is a specific navigational aid, usually a VOR or DME station, where the holding pattern begins. The aircraft will typically fly towards this fix and then enter the holding pattern once it reaches the specified distance or time.
The holding fix is identified on aviation charts and is crucial for pilots to accurately navigate and enter the holding pattern. It serves as the reference point for inbound and outbound tracks.
2. Inbound and Outbound Tracks
In a standard holding pattern, there are specific inbound and outbound tracks that pilots must follow. The inbound track is the course the aircraft flies from the holding fix towards the holding pattern. The outbound track, on the other hand, is the reciprocal of the inbound track and is used to ensure proper spacing between aircraft in the holding pattern.
The inbound and outbound tracks are typically depicted on aviation charts and are essential for maintaining proper navigation within the holding pattern.
3. Leg Length
The leg length refers to the distance between the holding fix and the specific points along the inbound and outbound tracks. In a standard holding pattern, the leg length is typically 1 minute, which corresponds to a specific distance based on the aircraft’s groundspeed.
The leg length is crucial for maintaining proper spacing between aircraft and ensuring that each aircraft spends a specific amount of time in the holding pattern.
4. Turn Direction
Turn direction refers to the direction in which the aircraft turns when transitioning from the outbound to inbound track or vice versa. In a standard holding pattern, the turn direction is typically specified as either “left-hand turns” or “right-hand turns.”
The turn direction is important for maintaining consistent traffic flow and ensuring that all aircraft within the holding pattern are turning in the same direction.
Conclusion
Holds play a crucial role in aviation by allowing air traffic control to manage traffic flow and maintain safe separation between aircraft. Understanding the different types of holds and the key elements of a standard holding pattern is essential for pilots and air traffic controllers to ensure efficient and safe operations in the skies.
Whether it’s a standard hold at a VOR or a non-standard hold created on the fly, pilots must be able to execute holding procedures accurately and efficiently. By following the established procedures and communication protocols, pilots can safely navigate their aircraft through holding patterns and maintain the integrity of the air traffic system.