Don't just take off because u are cleared

As a teenager we would park on the road just off the end of the runways at the old John Connally AFB out side of Waco. I don't remember what airline, but nightly we would watch 707s doing touch and goes. I mean the road was just off the end of the runway. If we went through the 4 string barbed wire fence we would be on the warning track.

Usually about 1.5 to 2 minutes after the plane departed, we would hear a slight whistling noise and the tree tops would just start whipping around. We never felt a bit of air movement right under the path of the jets. I mean seriously whipping around. We always thought it was from the jet engines when applying power for the go part of the T&G.

Later when I started flight training I realized it was the vortices coming off the wings as the plane flew over.

Really impressive strength.
 
mscard88 said:
I would have called the tower chief and have a discussion. NEVER allow a controller to rush you.
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Thanks

There is one controller at this tower that can be weird sometimes. They've denied our practice approach requests in the past when they've had 3-4 planes in the pattern. Granted, their RNAV approach puts you head on with the typical pattern... but other controllers just amend the MDA to 1K above TPA for us and don't give us any grief

My CFI has called them in the past to inquire about other issues, but I try to lay low. The flying community is small so I try to not ruffle too many feathers
 
Zeldman said:
Usually about 1.5 to 2 minutes after the plane departed, we would hear a slight whistling noise and the tree tops would just start whipping around.
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Always thought that was awesome

If anyone has ever golfed at Balboa Park golf course then you can sometimes see (or rather, hear) the same thing as the SAN approach comes right over the course. The occasional 767 and 757 can definitely be heard making a strange wooshing sounds as the air mass comes down through the trees there (can't feel it though). The 757 seems to do it worse than the BA 777
 
Tantalum said:
Thanks

There is one controller at this tower that can be weird sometimes. They've denied our practice approach requests in the past when they've had 3-4 planes in the pattern. Granted, their RNAV approach puts you head on with the typical pattern... but other controllers just amend the MDA to 1K above TPA for us and don't give us any grief

My CFI has called them in the past to inquire about other issues, but I try to lay low. The flying community is small so I try to not ruffle too many feathers
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Unfortunately individual controllers have their limits on how much traffic they can handle. There are weak sisters out there. I worked with quite a few in the Air Force. One guy would full stop fighters when he had more than 3-4 in the pattern. So I didn't assign him to local control when he was under my supervision. That's when it's fun and challenging, when you get 8-12 fighters in the pattern!
 
Tantalum said:
I've never heard of a 3 min separation for departing aircraft (doesn't mean there isn't one, just never had a CFI tell me about it). Last time I was at John Wayne in the Archer we were instructed to line up and wait pretty much right after a SW 737 started down the runway. Not long after his lift off we were cleared for take off. I just used the rules we were taught about the vorticies, and how to plan take off and touchdown
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Sounds like you made a good decision. The only 3 min rule (dep/dep same rwy) would be if you departed an intersection more than 500ft down the runway after the 737. That would have been waiver-able but I wouldn't. Same departure point, you just depart and will lift off prior to their rotation point and off-set upwind if needed depending on turn out. All the controller needed was 6000ft and airborne between you and the 737.
 
Radar Contact said:
Yes sir. As I know you are aware Greg but maybe a refresher to those who aren't, the vortices descend at about 300-500 fpm. In the OP's case let's assume the long landing aircraft crossed the threshold at a super high 250 ft (not probable). In 30-40 seconds they are at the ground. No way the preceding arrival is off the runway with you rolling down it in less time. This is why the rules governing wake for every arrival/departure scenario don't include a departure behind an arrival on the same runway.

*To each their own and people can exercise whatever caution level they are comfortable with. If you ever fly into a busy airport and you insist on 3 min you may not be departing for a while if aircraft are touching down every 1 1/2-2 mins and hopefully you aren't blocking access to the runway for others.
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Good to know. Didn't think about that

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Had San Juan ATC clear me for takeoff in a c-182 immediately after a 767 landed. I waited 5 minutes. As a aside those big turboprops such as the ATR churn up plenty of air with those big slow turning props, a friend in a Aztec had a funky ride following one out.
 
At KFUL, there’s a lot of helicopter activity. I was cleared for takeoff after a helicopter touched down, and was advised of wake turbulence. I should have waited, but instead I extended the roll past the helicopter (felt the turbulence) then went full power to take off. Luckily LSAs have good takeoff performance. But in hindsight, I should have declared “unable” as well, and waited 3 minutes.
 
WannFly said:
Not sure where to post hence posting here. Today holding short of 18, told tower I am ready for departure. Didn't look at final, my bad, before calling in. Tower came back with hold short for landing traffic as I looked towards final and saw a dual jet in the air. It was a MD-80 I believe, alleging air. As it flew to touchdown I could actually see the trail of wake , looked pretty cool. Noted the touchdown point and reset my timer to ensure 3 min delay. Winds were rt down the runway at 6 kts. Exactly 20 seconds later tower came back and said cleared for take off, caution wake turbulance.

I was under the impression that controllers are required to give a 3 min separation. Anyway, I responded with unable, will hold for another 2 mins, then got the take off clearance again after 2:30 seconds.

May be MD-80 doesn't generate as much wake as a 747, but I just wasn't comfortable taking off right after a dual jet landing and ensuring I take off after it's touchdown point, which was about 4000 ft down the runway.

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I was taught to go by where a heavy's nose wheel touches down. I'm not sure whether you meant that or the mains. I assume that the reasoning is that the wing makes much less lift once the angle of attack is reduced, thereby generating much less in the way of wingtip vortices.

I think I was taught two minutes rather than three, but this was 26 years ago, so I could be misremembering.
 
3 minutes - the "shun brothers" meaning if you are departing behind a large aircraft and you are at the intersection, there is a 3 minute (waiver-able by you) wake turbulence advisory. OR if you are departing behind a large aircraft of which either one of you are opposite direction, then again expect a three minute (waiver-able by you) wake turbulence advisory. And as someone said above, this is successive departures. This also applies if the large aircraft conducts a low approach.

2 minutes - If you are departing behind a heavy aircraft from the same departing point, then your wake turbulence is two minutes (not waiver-able) Only time it isn't waiver-able is if the departure was a heavy.

Large aircraft - any aircraft of more than 12,500 pounds maximum certificated takeoff weight.

But in the OP's case, there is no mandatory wake turbulence wait if you are departing after a large aircraft has landed; they just need to be off the runway. If you want to wait, fine but hopefully not when others are stacked up behind you.
 
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Tantalum said:
Always thought that was awesome

If anyone has ever golfed at Balboa Park golf course then you can sometimes see (or rather, hear) the same thing as the SAN approach comes right over the course. The occasional 767 and 757 can definitely be heard making a strange wooshing sounds as the air mass comes down through the trees there (can't feel it though). The 757 seems to do it worse than the BA 777
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757 was not considered a "heavy" when it first started flying. They soon realized that it put out quite a bit of wake turbulence. That's the reason for the heavy designation.
 
Paulie said:
757 was not considered a "heavy" when it first started flying. They soon realized that it put out quite a bit of wake turbulence. That's the reason for the heavy designation.
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And after further studies they have since changed the rules again. 757's are no longer considered Heavy's or something in-between either. They are wake recat class D. That is the same as 737's, Airbus 318-321's, Gulfstream 5 and 6's, and Embrier 190,195's for comparison. Most everyone get's 2 1/2 miles behind them now except for very small aircraft (i.e. the typical light GA plane would get 4 behind all those listed).
 
rtk11 said:
At KFUL, there’s a lot of helicopter activity.
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And the people in those whirly birds have guns and badges!

[I used to be in RIFC, and when I visit family in the area I still use Fun Outside's planes. Both are at General Aviation so real close to them peeps]
 
Radar Contact said:
And after further studies they have since changed the rules again. 757's are no longer considered Heavy's or something in-between either. They are wake recat class D. That is the same as 737's, Airbus 318-321's, Gulfstream 5 and 6's, and Embrier 190,195's for comparison. Most everyone get's 2 1/2 miles behind them now except for very small aircraft (i.e. the typical light GA plane would get 4 behind all those listed).
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Didn't know that, thanks. But like I said big turboprops are surprisingly bumpy to get behind.
 
Radar Contact said:
And after further studies they have since changed the rules again. 757's are no longer considered Heavy's or something in-between either. They are wake recat class D. That is the same as 737's, Airbus 318-321's, Gulfstream 5 and 6's, and Embrier 190,195's for comparison. Most everyone get's 2 1/2 miles behind them now except for very small aircraft (i.e. the typical light GA plane would get 4 behind all those listed).
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A320 family puts out some mean a$$ wake. They also love taxiing at grandpa speed but that’s another rant.

Anytime I see the winds showing 12kts or less , especially if it’s a quartering tailwind, I suspect I’ll be getting some wake. There is times I’ve declined takeoff clearance if I think we’re to close.
 
Tantalum said:
I've never heard of a 3 min separation for departing aircraft (doesn't mean there isn't one, just never had a CFI tell me about it). Last time I was at John Wayne in the Archer we were instructed to line up and wait pretty much right after a SW 737 started down the runway. Not long after his lift off we were cleared for take off. I just used the rules we were taught about the vortices, and how to plan take off and touchdown
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I was thinking about this too as I fly out of John Wayne. As you know, there are two runways, 20L and 20R. The left runway is short at about 3,000 feet while the right runway is about 5,700 feet and, thus, is the one used by the Boeing 737s and Airbus A320s.

If you're departing with a heading of 220 ("Mesa") or 330 ("Orange"), Tower will usually give you 20R so you can turn to heading as soon as you're comfortable, rather than 20L and have you turn across 20R's departure path.

That often means they're trying to fit you between two airline departures. With a continuous series of airline departures, it's not impossible, but it sure would be difficult to wait for 2-3 minutes if you ever wanted to get out.
 
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