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In aviation, holding (or flying a hold) is a maneuver designed to delay an aircraft already in flight while keeping it within a specified airspace; i.e. "going in circles." [1]
| | This article needs additional citations for verification .(May 2011) |
In aviation, holding (or flying a hold) is a maneuver designed to delay an aircraft already in flight while keeping it within a specified airspace; i.e. "going in circles." [1]
A holding pattern for instrument flight rules (IFR) aircraft is usually a racetrack pattern based on a holding fix. This fix can be a radio beacon such as a non-directional beacon (NDB) or VHF omnidirectional range (VOR). The fix is the start of the first turn of the racetrack pattern. [2] Aircraft will fly towards the fix, and once there will enter a predefined racetrack pattern. A standard holding pattern uses right-hand turns and takes approximately 4 minutes to complete (one minute for each 180-degree turn, and two one-minute straight ahead sections). [1] Deviations from this pattern can happen if long delays are expected; longer legs (usually two or three minutes) may be used, or aircraft with distance measuring equipment (DME) [2] may be assigned patterns with legs defined in nautical miles rather than minutes.
The primary use of a holding pattern is to delay aircraft that have arrived at their destination but cannot land yet because of traffic congestion, poor weather, or runway unavailability (for instance, during snow removal or emergencies). Several aircraft may fly the same holding pattern at the same time, separated vertically by 300 m (1,000 ft) or more. This is generally described as a stack or holding stack. As a rule, new arrivals will be added at the top. The aircraft at the bottom of the stack will be taken out and allowed to make an approach first, after which all aircraft in the stack move down one level, and so on. Air traffic control (ATC) will control the whole process, in some cases using a dedicated controller (called a stack controller) for each individual pattern.
One airport may have several holding patterns; depending on where aircraft arrive from or which runway is in use, or because of vertical airspace limitations.
Since an aircraft with an emergency has priority over all other air traffic, it will always be allowed to bypass the holding pattern and go directly to the airport (if possible). This causes more delays for other aircraft already in the stack. [3]
The entry to a holding pattern is often the hardest part for a novice pilot to grasp, and determining and executing the proper entry while simultaneously controlling the aircraft, navigating and communicating with ATC requires practice. There are three standard types of entries: direct, parallel, and offset (teardrop). The proper entry procedure is determined by the angle difference between the direction the aircraft flies to arrive at the beacon and the direction of the inbound leg of the holding pattern. [4]
The parallel and teardrop entry are mirrored in case of a left-hand holding pattern.
Maximum holding speeds are established to keep aircraft within the protected holding area during their one-minute (one-minute and a half above 4,300 m (14,000 ft) MSL) inbound and outbound legs. For civil aircraft (not military) in the United States and Canada, these airspeeds are: [1] [5]
The ICAO Maximum holding speeds: [6]
With their higher performance characteristics, military aircraft have higher holding speed limits.
In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR).
In aviation, visual flight rules (VFR) are a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Specifically, the weather must be better than basic VFR weather minima, i.e., in visual meteorological conditions (VMC), as specified in the rules of the relevant aviation authority. The pilot must be able to operate the aircraft with visual reference to the ground, and by visually avoiding obstructions and other aircraft.
According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a human-made surface or a natural surface. Runways, taxiways and ramps, are sometimes referred to as "tarmac", though very few runways are built using tarmac. Takeoff and landing areas defined on the surface of water for seaplanes are generally referred to as waterways. Runway lengths are now commonly given in meters worldwide, except in North America where feet are commonly used.
An airfield traffic pattern is a standard path followed by aircraft when taking off or landing while maintaining visual contact with the airfield.
Wake turbulence is a disturbance in the atmosphere that forms behind an aircraft as it passes through the air. It includes several components, the most significant of which are wingtip vortices and jet-wash, the rapidly moving gases expelled from a jet engine.
In aeronautics, a descent is any time period during air travel where an aircraft decreases altitude, and is the opposite of an ascent or climb.
In the United States, airways or air routes are defined by the Federal Aviation Administration (FAA) in two ways:
The world's navigable airspace is divided into three-dimensional segments, each of which is assigned to a specific class. Most nations adhere to the classification specified by the International Civil Aviation Organization (ICAO) and described below, though they might use only some of the classes defined below, and significantly alter the exact rules and requirements. Similarly, individual nations may also designate special use airspace (SUA) with further rules for reasons of national security or safety.
In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft operating under instrument flight rules from the beginning of the initial approach to a landing, or to a point from which a landing may be made visually. These approaches are approved in the European Union by EASA and the respective country authorities and in the United States by the FAA or the United States Department of Defense for the military. The ICAO defines an instrument approach as "a series of predetermined maneuvers by reference to flight instruments with specific protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter, if landing is not completed, to a position at which holding or en route obstacle clearance criteria apply."
Procedural control is a method of providing air traffic control services without the use of radar. It is used in regions of the world, specifically sparsely populated land areas and oceans, where radar coverage is either prohibitively expensive or is simply not feasible. It also may be used at very low-traffic airports, or at other airports at night when the traffic levels may not justify staffing the radar control positions, or as a back-up system in the case of radar failure.
Standard instrument departure (SID) routes, also known as departure procedures (DP), are published flight procedures followed by aircraft on an IFR flight plan immediately after takeoff from an airport.
The United States airspace system's classification scheme is intended to maximize pilot flexibility within acceptable levels of risk appropriate to the type of operation and traffic density within that class of airspace – in particular to provide separation and active control in areas of dense or high-speed flight operations.
On Christmas Eve 1996, a Learjet 35A business jet disappeared near Dorchester, New Hampshire, United States. The crash led to the longest missing aircraft search in the state's history, lasting almost three years. Media attention eventually resulted in congressional legislation mandating improved emergency locator transmitters (ELTs) be installed in U.S.-registered business jets.
In aeronautics, the final approach is the last leg in an aircraft's approach to landing, when the aircraft is lined up with the runway and descending for landing. In aviation radio terminology, it is often shortened to "final".
Inex-Adria Aviopromet Flight 1308 was a McDonnell Douglas MD-81 aircraft operating a Yugoslavian charter flight to the French island of Corsica. On 1 December 1981, the flight crashed on Corsica's Mont San-Pietro, killing all 180 people on board. The crash was the deadliest and first major aviation accident involving a McDonnell Douglas MD-80.
Indian Airlines Flight 257 was an Indian Airlines domestic passenger flight operating on the Calcutta–Imphal–Dimapur route. On 16 August 1991, the Boeing 737-2A8 registered VT-EFL crashed into the hilly terrain of Thangjing Hill during its descent, killing all 63 passengers and 6 crew members on board.
Modern United States Navy aircraft carrier air operations include the operation of fixed-wing and rotary aircraft on and around an aircraft carrier for performance of combat or noncombat missions. The flight operations are highly evolved, based on experiences dating back to 1922 with USS Langley.
Dan-Air Flight 1008 was a fatal accident involving a Boeing 727-46 jet aircraft operated by Dan Air Services Limited on an unscheduled international passenger service from Manchester to Tenerife. The crash occurred on 25 April 1980 in a forest on Tenerife's Mount La Esperanza when the aircraft's flight deck crew wrongly executed an unpublished holding pattern in an area of very high ground; it resulted in the aircraft's destruction and the deaths of all 146 on board. Flight 1008 was Dan-Air's second major accident in ten years and the worst accident involving the deaths of fare-paying passengers in the airline's entire history.
Elizabethtown Regional Airport, also known as Addington Field, is a public use airport located four nautical miles (7 km) west of the central business district of Elizabethtown, a city in Hardin County, Kentucky, United States. The airport is owned by the Elizabethtown Airport Board. It is used for general aviation, but current exploration of commercial aviation is underway.
A teardrop turn is a method of reversing the course of an aircraft or vessel so that it returns on its original path, travelling in the opposite direction, and passes through a specified point on the original path.
ATP, CFI-AI, (2016), https://www.holdingpattern.com/holding-patterns.html
