If you’ve ever browsed airspace around a busy airport on Flightradar24, you’ve likely noticed aircraft circling in oval, racetrack-like loops. These loops are called holding patterns, and they play a crucial role in air traffic management and flight safety.
What is a holding pattern?
A holding pattern is a standardised racetrack-shaped flight path that aircraft fly while awaiting further clearance from air traffic control (ATC). Aircraft may be instructed to enter a hold when approaching congested airports, during periods of bad weather, or if there’s a need to delay an approach for sequencing or separation.
Each holding pattern is centred around a ‘holding fix’, which is typically a navigational beacon (such as a VOR, NDB, or GPS waypoint). Aircraft fly the pattern at a designated altitude and airspeed until they’re cleared to exit the hold and continue their route.
Why do aircraft enter holding patterns?
Aircraft enter holding patterns for several key reasons:
- Airspace congestion: Busy airports like JFK, Heathrow, or Frankfurt may use holding patterns to manage inbound traffic during peak hours.
- Weather disruptions: Low visibility, thunderstorms, or strong crosswinds may delay landings, requiring aircraft to wait in a hold until conditions improve.
- Runway availability: When runways are temporarily closed due to incidents or snow clearance, aircraft are often placed in a holding pattern.
- Emergencies or technical Issues: Pilots may enter a hold to troubleshoot issues or burn fuel before landing overweight.
In an emergency, aircraft squawk 7700 on their transponder. You can monitor such alerts on Flightradar24 by setting up a general emergency notification.
How do aircraft enter holding patterns?
Before flying a hold, pilots must determine the best entry procedure based on their direction of arrival. There are three standard holding pattern entry types:
- Direct entry: The aircraft flies straight to the fix and enters the pattern.
- Parallel entry: The aircraft flies over the fix, turns outbound on the reciprocal heading for one minute, then turns back toward the holding pattern.
- Teardrop (Offset) entry: The aircraft flies over the fix, turns about 30 degrees off the inbound course for one minute, then turns back toward the inbound leg.
Pilots choose the entry method based on their bearing to the fix, following ICAO or FAA guidance depending on airspace jurisdiction. That said, pilots at busy airports are often vectored (or directed by ATC) into the hold in a way that most conveniently fits the traffic flow.
Where are holding patterns used?
Whilst holds can occur en route at (theoretically) any waypoint, they’re most commonly used near major international airports. Here are a few notable examples:
John F. Kennedy International Airport (JFK), New York
JFK sees heavy transatlantic and domestic traffic, and has several published holding patterns:
- CAMRN arrival: Holding over CAMRN waypoint during peak arrivals.
- DIXIE fix: Often used for aircraft arriving from the south.
- HAPIE, and GREKI are other common fixes where holds occur during busy arrival banks.
London Heathrow (LHR)
Heathrow regularly holds aircraft over four key VORs: Bovingdon (BNN), Biggin (BIG), Lambourne (LAM), and Ockham (OCK). These holds help sequence aircraft into the final approach path during busy arrival periods.
How to spot holding patterns on Flightradar24
Here are a few tips to help you spot aircraft holding in real time:
- Monitor high-traffic airports: Airports like JFK, LHR, FRA, ATL, and LAX often have aircraft in holding patterns during peak traffic periods.
- Try our Airport Disruption Index: On Flightradar24, a high disruption rating usually means delays and more holding traffic.
- Enable ‘Navaids’ on your map: Adding navigational aids (such as VORs and NDBs) to your map can reveal the fixes around which aircraft are holding.
Holding patterns are a vital part of air traffic management, keeping skies safe and organised during times of high demand or unexpected delays. Next time you spot those racetracks on Flightradar24, you’ll know exactly what’s going on and why some pilots seem to be flying in circles.
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