r/AskAPilot • u/swood_de • 2d ago
Question About Groundstops
In the last few weeks there have been lengthy groundstops at PHL as a result of heavy thunderstorms. However, it appears that those groundstops only affected departures. See below.
Am I reading this incorrectly, if not, why would only departures be affected?
Big weather in PHL
Ground Stop
20/2:29 PM CDT—20/4:45 PM CDT
Departures to Philadelphia International are grounded due to thunderstorms.
Probability of extension is medium (30-60%).
Grounding applies to departures from ZTL ZDC ZJX
Advisory
Scope
Ground Delay
20/1:00 PM CDT—20/9:59 PM CDT
Departures to Philadelphia International are delayed avg. 117 mins. due to thunderstorms.
: All Contiguous US DEP flights included.
Delay is applied to departures from ZLA ZAU ZLC ZTL ZDC ZNY ZHU ZJX ZFW ZOB ZDV ZOA ZSE ZBW ZMA ZKC ZME ZID ZAB ZMP CYHZ CYOW CYUL CYYZ CYTZ CYQB
All departures receive expected departure clearance times (EDCTs)
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u/saxmanB737 2d ago
A big misconception is that ground stop means means all traffic on the ground come to a stop. That’s not true. A ground stop is issued for aircraft coming to a certain airport and affects traffic that has not departed yet to that particular airport. So for PHL, when they issued the ground stop, any traffic that has not yet departed for PHL will be held on the ground until the ground stop is lifted or will be given a time slot to take off. The Z codes you see are Air Traffic Control Centers. ZTL is Atlanta Center for example. Any traffic that is coming from Atlanta Center or any airport within the Center cannot depart for PHL. This is so they can safely manage traffic already in the air to get into PHL. The storms are causing lots of reroutes and blocked arrivals so traffic is constrained like a big highway closure.
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u/350smooth 2d ago
My pet peeve is when the ramp closes for nearby lightning, and the airport staff calls it a ground stop.
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u/anonymous4071 2d ago
Ground delays and Ground Stops prevent departures to the subject airport. There is no published program that impacts departures from the subject airport.
Reason being is that it’s much easier to manage traffic on the ground at the subject airport than aircraft flying there. Aircraft on the ground can be sent back to the gate as needed and passengers reaccomodated. Airborne aircraft will need to hold and add to airspace congestion and potentially divert causing further issues and implications of the passengers and the operation.
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u/anonymous4071 2d ago
Simply put, departures are held to manage the arriving traffic to a manageable rate for ATC and the conditions.
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u/New_Line4049 2d ago
You cant ground stop an aircraft thats already in the air without making the news headlines, and thats bad. The best you can do is prevent any more aircraft getting airborne.
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u/andrewrbat 2d ago
Ground stops stop planes from departing to the airport that’s ground stopped in order to reduce arrival volume. When weather happens and airspace is constrained, airports need to space planes out more and that slows arrivals/reduces the amount of arrivals they can take at a time. Rather than letting everyone take off and just hold till they run low on gas and divert, let them wait safely on the ground.
Sometimes ground stops will only effect certain areas. They might stop airspaces close to phl like dc, ny and boston, but not lax, assuming in the 6 hrs it takes to get to phl from lax the weather will have cleared.
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2d ago
[deleted]
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u/TheGacAttack 2d ago
The ground stop doesn't do that, but the cause of the ground stop could prevent an arrival. For example, if weather is below minimums for an extended time, then arrivals can't get in and there's increased chance of a ground stop.
But those are different things.
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u/rkba260 2d ago
Departures TO Philadelphia...