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Go/No-Go As Bad Weather Approaches  
User currently offlinelaurco From United States of America, joined Oct 2011, 4 posts, RR: 0
Posted (9 months 3 weeks 3 days 20 hours ago) and read 3066 times:

I was on Delta 26 June 13 from ATL to JFK. A real bad storm was approaching from the North, dark skies, lightning, winds starting to pick up. We left the gate and sat on taxiways for a while, there were periods where no planes were departing or landing. Pilot advised we were number 14 for takeoff and it would be a wait. The sky overhead was getting really dark with low black clouds and the winds picking up more. It wasn't raining yet. At that point, no planes were departing. After several minutes the pilot advises we are number one for takeoff, and he cuts across the line to the runway, and off we go. It was a rather unpleasant and "scary" takeoff (for the passengers anyway) with winds really ripping and the plane getting tossed around as we banked hard to the South to try to avoid the incoming storm.

So that leads me to my questions about how and who makes the decisions on taking off in bad weather.

1. I understand the pilot has final decision. I assume the tower has the ability to put in a ground stop that can't be violated, correct?

2. Are there specific rules or conditions on when take-offs are prohibited by either tower or pilots? I.E. winds, or lightning, or is it basically judgement?

3. What might have happened that we would go from number 14 to number 1 - did other pilots choose not to take-off and wait but our pilot was going for it? Or is it just too hard to speculate.

Thanks for any insight for this regular flier.

12 replies: All unread, jump to last
 
User currently offlinerfields5421 From United States of America, joined Jul 2007, 7345 posts, RR: 32
Reply 1, posted (9 months 3 weeks 3 days 20 hours ago) and read 3051 times:

Quoting laurco (Thread starter):
1. I understand the pilot has final decision. I assume the tower has the ability to put in a ground stop that can't be violated, correct?

I'm not sure the tower has the authority to stop operations in all cases. But for example, at KDFW - the tower is often evacuated in certain strong storm conditions. No tower - no takeoffs.

It is a lot simplier to delay landings or divert aircraft away from the airport. Taking off aircraft in line as the severe weather is increasing are a bigger problem. Is the aircraft safer to be in the air and getting away from the storm? or, going back to the ramp where there are likely no open gates and making the passengers ride out the storm on a closed up aircraft, wait for refuel and get back in line for takeoff.

Quoting laurco (Thread starter):
2. Are there specific rules or conditions on when take-offs are prohibited by either tower or pilots? I.E. winds, or lightning, or is it basically judgement?

There are very specific limits on crosswinds and visibility for takeoff. As I mention above - lightning, wind or other conditions can close the tower. If the pilot took off as you stated - the conditions were legal for takeoff.

Quoting laurco (Thread starter):
3. What might have happened that we would go from number 14 to number 1 - did other pilots choose not to take-off and wait but our pilot was going for it? Or is it just too hard to speculate.

The desired route out of the airport was likely a factor. Often in such conditions, the number of takeoffs is limited to keep the number of aircraft in a certain corridor down. That can cause several aircraft to become 'unable' to takeoff.

Another issue might be fuel, some of the other 13 planes may not have had enough fuel on board to takeoff and fly a long way around route to avoid the weather.

That happened to me once at BDL when we jumped the line. The pilot told us he had taken on max fuel and was willing to fly an extra two hours on an extended route to get back to DFW (BDL-BTV-MSP-RAP-AMA-DFW - it was a long flight to avoid several major lines of storms)

Other planes might have getting to the point that they needed to return to the ramp and get more fuel.

Aircraft type also plays into that takeoff order. Your plane may have been legal to takeoff in that crosswind component, and some smaller regional types not legal.


User currently offlineN353SK From United States of America, joined Jun 2006, 792 posts, RR: 0
Reply 2, posted (9 months 3 weeks 3 days 19 hours ago) and read 3025 times:

It's possible that your flight was the only one going northeast and got to jump the line because the TRACON was accepting northeast departures but not other directions.

More plausible is that the airport was ground stopped for a while, and after the ground stop was lifted your flight got to cut the line because it was headed to JFK and had an EDCT (wheels up) time to meet.

The third thing I can think of is that your flight was rerouted, perhaps going to the southeast first to get around the weather before heading toward JFK. It's possible that your flight simply had the quickest dispatcher and was the first to be re-filed over a different departure fix.


User currently offlineMir From United States of America, joined Jan 2004, 21085 posts, RR: 56
Reply 3, posted (9 months 3 weeks 3 days 17 hours ago) and read 2972 times:

Quoting laurco (Thread starter):
I assume the tower has the ability to put in a ground stop that can't be violated, correct?

I don't believe the tower can put a stop on departures unless there is some problem with the tower functionality. The TRACON, however, will routinely stop departures for certain departure routes (or even the whole airport) if there's weather that's interfering with the airspace, and then the tower can't issue a takeoff clearance to the affected aircraft.

Quoting laurco (Thread starter):
Are there specific rules or conditions on when take-offs are prohibited by either tower or pilots? I.E. winds, or lightning, or is it basically judgement?

It's generally pilot judgement unless there's some factor like a runway closure.

Quoting laurco (Thread starter):
What might have happened that we would go from number 14 to number 1 - did other pilots choose not to take-off and wait but our pilot was going for it? Or is it just too hard to speculate.

Could be that other pilots chose not to take off (which shouldn't be interpreted as your pilot not being safety-conscious). Could be that the TRACON decided to accept your flight but not others (because your departure route was open and theirs wasn't). Could also be that there was some factor (like a wheels-up time) that led your flight to get out at a certain time, which would generally allow it to go ahead of the line.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2254 posts, RR: 16
Reply 4, posted (9 months 3 weeks 2 days 22 hours ago) and read 2784 times:

though there are x-wind and vis limits most pilots would be most concerned with windshear from an approaching storm. Many larger airports have the perimeter wind sensors that will warn crews of possible w/s.

User currently offlineIAHFLYR From United States of America, joined Jun 2005, 4790 posts, RR: 23
Reply 5, posted (9 months 3 weeks 2 days 20 hours ago) and read 2755 times:

Quoting Mir (Reply 3):
Could be that other pilots chose not to take off (which shouldn't be interpreted as your pilot not being safety-conscious). Could be that the TRACON decided to accept your flight but not others (because your departure route was open and theirs wasn't). Could also be that there was some factor (like a wheels-up time) that led your flight to get out at a certain time, which would generally allow it to go ahead of the line.


Sure is a bunch of "could be" floating around!   There are certainly many options when dealing with the OP questions.

Quoting Mir (Reply 3):
I don't believe the tower can put a stop on departures unless there is some problem with the tower functionality.


A tower controller certainly can stop departures, quite simple actually just don't clear them for take-off. Sounds simple and I'm sure many questions would have to be answered, but if I saw a storm that from my vantage point looked quite unfriendly I would not clear anyone for take-off, they can wait. Mind you I would get some reports from preceding departures and others in the TRACON and have done so then passed the information along to those waiting and asked if anyone wants to depart, never had any pilot choose to depart.

Quoting rfields5421 (Reply 1):
I'm not sure the tower has the authority to stop operations in all cases. But for example, at KDFW - the tower is often evacuated in certain strong storm conditions. No tower - no takeoffs.


No tower, then it's an uncontrolled airport. As long as a pilot was smart as to the regulations (Class B airspace maybe or IFR departure) and took the necessary clearances into account nothing wrong with them departing. Might not be very smart, but can be done.



Any views shared are strictly my own and do not a represent those of any former employer.
User currently offlinewoodreau From United States of America, joined Sep 2001, 978 posts, RR: 6
Reply 6, posted (9 months 3 weeks 2 days 18 hours ago) and read 2734 times:

Quoting laurco (Thread starter):
1. I understand the pilot has final decision. I assume the tower has the ability to put in a ground stop that can't be violated, correct?

2. Are there specific rules or conditions on when take-offs are prohibited by either tower or pilots? I.E. winds, or lightning, or is it basically judgement?

I've had an instance where I needed to take off on a runway the tower refused to issue a takeoff clearance. I really made sure that I had all the documentation supporting my decision lined up - had all the performance numbers, talked with the dispatcher and the airport authority/manager, made sure the restricted airspace off the end of the runway I wanted to use wasn't active. The tower controller wasn't going to let me take off on the runway I wanted.

The runway the tower wanted me to use for takeoff had in excess of a 35-40kt gusting crosswind. We landed on the runway - barely, but I decided that for departure we weren't using that runway and were going to use the perpendicular runway which was much much shorter - to the point where the controller didn't think I had enough runway for the takeoff.

Instead, he made me self-announce my taxi and takeoff and held all the other ground traffic to let me go where I needed to go to takeoff, all while making very clear on the tape recordings that he couldn't clear / refused to issue me clearance for takeoff on the runway I wanted.

It was the only time I've ever used self-announce/non-towered CTAF procedures at airport with an open and operating control tower.

After takeoff, the tower talked to me normally and switched me over to departure.



Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
User currently offlinerscaife1682 From United States of America, joined Feb 2008, 332 posts, RR: 0
Reply 7, posted (9 months 3 weeks 2 days 16 hours ago) and read 2695 times:

Looked like a fun ride

http://flightaware.com/live/flight/D...6/history/20130613/2154Z/KATL/KJFK


User currently offlineMSJYOP28Apilot From United States of America, joined Jul 2009, 204 posts, RR: 1
Reply 8, posted (9 months 3 weeks 2 days 12 hours ago) and read 2633 times:

A groundstop normally is not issued by a tower. A groundstop comes from the FAA command center or enroute center.

A groundstop effects traffic departing to an airport, not from an airport. Weather in ATL wouldn't groundstop ATL departures but rather flights arriving into ATL that are still on the ground at their point of origin. Groundstops will have varied scopes depending on how long the constraint is projected to remain on the system. A groundstop is a method of flow control.

Most departure stops are either TRACON initiated due to route constraints or air crew initiated. Towers normally do all they can to keep traffic moving. Windshear on the field normally stops departures.

Often, the tower will clear an aircraft to line up and wait and have him check his radar to see if he will accept a departure.

Often during thunderstorm events, the tower will often suspend operations for departures and TRACON for arrivals to allow the weather to clear the field. As soon as the weather clears, they start actively seeking volunteers to serve as pathfinders around the weather. Normally you see this at hubs as ATC gets concerned with aircraft deviating and going missed approach and infringing on traffic flows. But once the weather clears, it wants to get things moving again.

At smaller towered airports and non-towered airports, it is often up to the pilots discretion whether to takeoff and land. Normally it is just at hubs where ATC puts a halt to departures and arrivals due to the flow control issues. Not every airport even has windshear detection equipment. Many towered operations don't.

Often, when TRACON refuses to accept departures to certain fixes or demands large amount of MIT/MINIT spacing, the ATC command center is trying to coordinate CDR and other re-routes to less constrained fixes.

The main issue with thunderstorms is that they require deviations that interfere with competing traffic flows. This is where you see the most severe delays. In less busy airspace, it is much easier for planes to takeoff and deviate around weather than in busier airspace. Because traffic flows are less of an issue, ATC leaves much of the decision making to pilots and dispatchers outside of the busiest of airspace.


User currently offlineIAHFLYR From United States of America, joined Jun 2005, 4790 posts, RR: 23
Reply 9, posted (9 months 3 weeks 1 day 20 hours ago) and read 2488 times:

Quoting MSJYOP28Apilot (Reply 8):
Most departure stops are either TRACON initiated due to route constraints or air crew initiated.



An excellent post, but you might be surprised how often a so called departure stop is initiated by a tower or center. If the center won't take any airplanes out over a specific fix they will issue a stop on that route.

Quoting MSJYOP28Apilot (Reply 8):
Often, when TRACON refuses to accept departures to certain fixes or demands large amount of MIT/MINIT spacing, the ATC command center is trying to coordinate CDR and other re-routes to less constrained fixes.



Most MIT/MINIT are the result of a center requiring them and the TRACON is forced to hand them down to a tower/s which often times are greater than what the center needed so the departure controllers can fit the airplanes from the terminal area into the conga line over the departure fix, while providing what the center issues for MIT/MINIT.



Any views shared are strictly my own and do not a represent those of any former employer.
User currently offlineBoeing77w From United Kingdom, joined May 2007, 200 posts, RR: 0
Reply 10, posted (9 months 3 weeks 1 day 10 hours ago) and read 2394 times:

Departures from the London TMA and surrounding area are certainly subject to slot restrictions in order to reduce flow rates when there is bad weather in the surrounding area. Storms over the channel can have a big impact on departures from the Southern UK. Obviously as mentioned in previous posts, this sort of restriction is enforced by enroute ATC.

From a Pilots perspective there is usually an absolute limit on wind speeds, in our Manuals winds in excess of 60kts including gusts will stop all ground operations and movements until the wind has reduced below this value for a period of 30 minutes. There are also the normal cross wind limits which need to be observed. In terms of thunderstorms over the field on departure, I wouldn't want to take off into one! You can run into other issues too, fuelling usually stops when storms are over the field and this will obviously have the knock on effect of preventing aircraft from going anywhere.


User currently offlinespeedbird128 From Pitcairn Islands, joined Oct 2003, 1648 posts, RR: 2
Reply 11, posted (9 months 3 weeks 1 day 10 hours ago) and read 2387 times:

Quoting Mir (Reply 3):
I don't believe the tower can put a stop on departures

I have. Not a huge amount of times I will grant you that, but I am trained in WX know the local conditions better than a pilot flying through. The windshear and downdraughts from the storms was as nasty on approach as it was on departure.

I don't make a decision lightly to withold a departure clearance, but if I am of the opinion that its really not a good idea I will generally have a discussion with the crew about it. I don't need a smoking crater on my shift.

I am not in towers anymore, but I wish that somebody had witheld some clearances in the past. There was B06 missing for about 5 years due to a "I can take off and land in any weather" scenario. They said to tower they could follow the coast under 300' which would be below the cloud base and they could set down anywhere on the beaches. They never arrived and were never found until recently. They were jammed into forest on a mountainside.



A306, A313, A319, A320, A321, A332, A343, A345, A346 A388, AC90, B06, B722, B732, B733, B735, B738, B744, B762, B772, B7
User currently offlineFlyHossD From United States of America, joined Nov 2009, 748 posts, RR: 2
Reply 12, posted (9 months 2 weeks 2 days 19 hours ago) and read 1964 times:

Quoting IAHFLYR (Reply 5):
Sure is a bunch of "could be" floating around!   There are certainly many options when dealing with the OP questions...

...No tower, then it's an uncontrolled airport.

Nice post, thank you.

Back to the OPs questions, I can recall at least two instances in my career where other Captains chose to wait and I didn't (and thus moved to the head of the line). In one of them, a "windshear alert" (IIRC) had been issued for a runway on the (far) other side of the airport, but not for the departure runway. There was a cell beyond the airport and it appeared to be passing aside. As there was no shear or even gusts at the runway, we departed and had a smooth ride with no issues at all.

So, as IAHFLYR wrote, there is a lot "could be" possible answers. My experience is an example of just one.



My statements do not represent my former employer or my current employer and are my opinions only.
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