CAUTION Wake Turbulence

As more & more pilots are aquiring self-launching or touring motorgliders they may find themselves flying from fields with private jet or tanker traffic.

Last weekend I was taxing my ASH-26e out to take-off from end of 34 at Minden. Most gliders are towed off of 30 so this usually isn't even an issue but because the 34 runway is so long many choose to self-launch mid field. I was taught you can't use the runway behind you & since I have to warm my engine before I take off, I used the time to taxi to the end of the runway.

About a minute before I reached the end of the runway, a Gulfstream landed on 34. As I taxied into position for take off, the Gulfstream was clearing the active runway. I proceeded with my take off roll and as I accelerated to about 45 kts, my left wing was slammed to the ground. Almost as quickly as this happened, I got the wings level and was airborne shortly thereafter. Obviously, I didn't think to wait a bit after the Gulfstream had landed but I hate to think what might have happened had I just gotten airborne!

Although we are all aware of wake turbulence, a valuable lesson was reinforced, fortunately without serious consequences.

On Tuesday, July 5, 2016 at 8:06:25 PM UTC-4, wrote:
As more & more pilots are aquiring self-launching or touring motorgliders they may find themselves flying from fields with private jet or tanker traffic.

Last weekend I was taxing my ASH-26e out to take-off from end of 34 at Minden. Most gliders are towed off of 30 so this usually isn't even an issue but because the 34 runway is so long many choose to self-launch mid field. I was taught you can't use the runway behind you & since I have to warm my engine before I take off, I used the time to taxi to the end of the runway..

About a minute before I reached the end of the runway, a Gulfstream landed on 34. As I taxied into position for take off, the Gulfstream was clearing the active runway. I proceeded with my take off roll and as I accelerated to about 45 kts, my left wing was slammed to the ground. Almost as quickly as this happened, I got the wings level and was airborne shortly thereafter. Obviously, I didn't think to wait a bit after the Gulfstream had landed but I hate to think what might have happened had I just gotten airborne!

Although we are all aware of wake turbulence, a valuable lesson was reinforced, fortunately without serious consequences.

Not only limited to Gulfstream jets or similar. Please review this investigation by the German Aerospace Center, which was triggered by an accident that killed three and severely injured the fourth occupant in this Robin DR400 tow plane. The DR400 is a very nimble plane but it could not escape the wing tip vortex of the Antonov AN-2:
http://www.dglr.de/publikationen/2014/340177.pdf
Uli

On Wednesday, July 6, 2016 at 12:06:25 PM UTC+12, wrote:
As more & more pilots are aquiring self-launching or touring motorgliders they may find themselves flying from fields with private jet or tanker traffic.

Last weekend I was taxing my ASH-26e out to take-off from end of 34 at Minden. Most gliders are towed off of 30 so this usually isn't even an issue but because the 34 runway is so long many choose to self-launch mid field. I was taught you can't use the runway behind you & since I have to warm my engine before I take off, I used the time to taxi to the end of the runway..

About a minute before I reached the end of the runway, a Gulfstream landed on 34. As I taxied into position for take off, the Gulfstream was clearing the active runway. I proceeded with my take off roll and as I accelerated to about 45 kts, my left wing was slammed to the ground. Almost as quickly as this happened, I got the wings level and was airborne shortly thereafter. Obviously, I didn't think to wait a bit after the Gulfstream had landed but I hate to think what might have happened had I just gotten airborne!

Although we are all aware of wake turbulence, a valuable lesson was reinforced, fortunately without serious consequences.

When I did some powered training it was at a pretty busy airport (WLG/NZWN) with a B737/A320 about every ten minutes and lots of smaller but still pretty serious turboprops between.

The key thing drummed into us on every takeoff and landing was to never go through or below air that a big guy had been through in the last several minutes WITH A NONZERO ANGLE OF ATTACK.

That runway was short enough that the jets used 2/3 - 3/4 of the length before rotation, while we needed about 1/8 of the length (250m). Operating from the midpoint, you could avoid wake turbulence by making a small turn immediately after liftoff (into wind, if there was a cross wind), and by flying always above the big guys' approach path on landing and use an aiming point past the 1000 ft markers. Not too much past though, as with another jet usually not far behind they'd usually tell us to maintain 100 kts on approach and we did still have to slow down enough to land and turn off at the midpoint.

Is 34 so much longer than 30 at Minden?

I was there last month in my Stemme and used the time to taxi to the end
of 30 to warm up the engine. I wonder, however, about departing 30
shortly after a heavy aircraft has departed on 34. You might very well
intercept his wake somewhere near the intersection of the two runways.

Thanks for the reminder about wake turbulence! It's not much of an
issue at Moriarty, though a few weeks ago, we had a lot of helicopters
working the big fire to the southwest. They were very thoughtful about
their operations and did not impact us other than occupying the man
taxiway on the west end. I think that was a price worth paying!


On 7/5/2016 6:06 PM, wrote:
As more & more pilots are aquiring self-launching or touring motorgliders they may find themselves flying from fields with private jet or tanker traffic.

Last weekend I was taxing my ASH-26e out to take-off from end of 34 at Minden. Most gliders are towed off of 30 so this usually isn't even an issue but because the 34 runway is so long many choose to self-launch mid field. I was taught you can't use the runway behind you & since I have to warm my engine before I take off, I used the time to taxi to the end of the runway.

About a minute before I reached the end of the runway, a Gulfstream landed on 34. As I taxied into position for take off, the Gulfstream was clearing the active runway. I proceeded with my take off roll and as I accelerated to about 45 kts, my left wing was slammed to the ground. Almost as quickly as this happened, I got the wings level and was airborne shortly thereafter. Obviously, I didn't think to wait a bit after the Gulfstream had landed but I hate to think what might have happened had I just gotten airborne!

Although we are all aware of wake turbulence, a valuable lesson was reinforced, fortunately without serious consequences.

--
Dan, 5J

On Thursday, July 7, 2016 at 3:51:02 AM UTC+12, Dan Marotta wrote:
Is 34 so much longer than 30 at Minden?

I was there last month in my Stemme and used the time to taxi to the end
of 30 to warm up the engine. I wonder, however, about departing 30
shortly after a heavy aircraft has departed on 34. You might very well
intercept his wake somewhere near the intersection of the two runways.

Thanks for the reminder about wake turbulence! It's not much of an
issue at Moriarty, though a few weeks ago, we had a lot of helicopters
working the big fire to the southwest. They were very thoughtful about
their operations and did not impact us other than occupying the man
taxiway on the west end. I think that was a price worth paying!

The heavy on 34 has 1000m to the intersection, you on 30 have 800m. (both measured on google maps, not paying attention to any runway markings)

I'd assume they'd be barely rotating my the intersection, and possibly well after it. You on the other hand are probably a few hundred feet up by then? If so, then no possible problem.

You could always turn right to 000 or beyond as soon as you're off. That should be able to be completed well before the intersection.

On Tuesday, July 5, 2016 at 8:06:25 PM UTC-4, wrote:
As more & more pilots are aquiring self-launching or touring motorgliders they may find themselves flying from fields with private jet or tanker traffic.

Last weekend I was taxing my ASH-26e out to take-off from end of 34 at Minden. Most gliders are towed off of 30 so this usually isn't even an issue but because the 34 runway is so long many choose to self-launch mid field. I was taught you can't use the runway behind you & since I have to warm my engine before I take off, I used the time to taxi to the end of the runway..

About a minute before I reached the end of the runway, a Gulfstream landed on 34. As I taxied into position for take off, the Gulfstream was clearing the active runway. I proceeded with my take off roll and as I accelerated to about 45 kts, my left wing was slammed to the ground. Almost as quickly as this happened, I got the wings level and was airborne shortly thereafter. Obviously, I didn't think to wait a bit after the Gulfstream had landed but I hate to think what might have happened had I just gotten airborne!

Although we are all aware of wake turbulence, a valuable lesson was reinforced, fortunately without serious consequences.

I remember seeing a video of a Lear that was flown about a mile behind a 747 and it was rolled 360 degrees.

Thanks for the measurements and, yes, I was up at least 100' by the
intersection (having departed from the end of the runway). Right
turnouts are not appreciated, however, by the sky divers who descend
east of the airport.


On 7/6/2016 12:35 PM, Bruce Hoult wrote:
On Thursday, July 7, 2016 at 3:51:02 AM UTC+12, Dan Marotta wrote:
Is 34 so much longer than 30 at Minden?

I was there last month in my Stemme and used the time to taxi to the end
of 30 to warm up the engine. I wonder, however, about departing 30
shortly after a heavy aircraft has departed on 34. You might very well
intercept his wake somewhere near the intersection of the two runways.

Thanks for the reminder about wake turbulence! It's not much of an
issue at Moriarty, though a few weeks ago, we had a lot of helicopters
working the big fire to the southwest. They were very thoughtful about
their operations and did not impact us other than occupying the man
taxiway on the west end. I think that was a price worth paying!
The heavy on 34 has 1000m to the intersection, you on 30 have 800m. (both measured on google maps, not paying attention to any runway markings)

I'd assume they'd be barely rotating my the intersection, and possibly well after it. You on the other hand are probably a few hundred feet up by then? If so, then no possible problem.

You could always turn right to 000 or beyond as soon as you're off. That should be able to be completed well before the intersection.


--
Dan, 5J

On Thursday, July 7, 2016 at 9:23:33 AM UTC-7, Dan Marotta wrote:
Thanks for the measurements and, yes, I was up at least 100' by the
intersection (having departed from the end of the runway). Right
turnouts are not appreciated, however, by the sky divers who descend
east of the airport.


On 7/6/2016 12:35 PM, Bruce Hoult wrote:
On Thursday, July 7, 2016 at 3:51:02 AM UTC+12, Dan Marotta wrote:
Is 34 so much longer than 30 at Minden?

I was there last month in my Stemme and used the time to taxi to the end
of 30 to warm up the engine. I wonder, however, about departing 30
shortly after a heavy aircraft has departed on 34. You might very well
intercept his wake somewhere near the intersection of the two runways.

Thanks for the reminder about wake turbulence! It's not much of an
issue at Moriarty, though a few weeks ago, we had a lot of helicopters
working the big fire to the southwest. They were very thoughtful about
their operations and did not impact us other than occupying the man
taxiway on the west end. I think that was a price worth paying!
The heavy on 34 has 1000m to the intersection, you on 30 have 800m. (both measured on google maps, not paying attention to any runway markings)

I'd assume they'd be barely rotating my the intersection, and possibly well after it. You on the other hand are probably a few hundred feet up by then? If so, then no possible problem.

You could always turn right to 000 or beyond as soon as you're off. That should be able to be completed well before the intersection.


--
Dan, 5J

If you take small airplane instruction wake turbulence avoidance is drummed into you. If you haven't had this instruction, because you have a glider license and buy a MG, this may come as a very rude introduction. Basically, you can avoid it by using ONLY the part of the runway that the big guys are on the ground (they need a lot of it, so it shouldn't be hard). Taking off from the numbers, however, can be problematic.

Tom

"Basically, you can avoid it by using ONLY the part of the runway that
the big guys are on the ground (they need a lot of it, so it shouldn't
be hard)."

Thanks, but I received my training in the US Air Force and I have
experienced wake turbulence in the real world. I have flown jets from
the T-37 to the B-727-200, recips from a Cub up to the Be-95, and the
King Air, and have flown out of grass, gravel, DFW, O'Hare, LAX, etc.

Still I think this was a good discussion which helped inform those who
don't know and refresh those who do. And don't forget, if the big guy
is on the ground and his nose wheel is off the ground, he's still
generating a pretty big pair of vortices.

On 7/21/2016 10:44 PM, 2G wrote:
On Thursday, July 7, 2016 at 9:23:33 AM UTC-7, Dan Marotta wrote:
Thanks for the measurements and, yes, I was up at least 100' by the
intersection (having departed from the end of the runway). Right
turnouts are not appreciated, however, by the sky divers who descend
east of the airport.


On 7/6/2016 12:35 PM, Bruce Hoult wrote:
On Thursday, July 7, 2016 at 3:51:02 AM UTC+12, Dan Marotta wrote:
Is 34 so much longer than 30 at Minden?

I was there last month in my Stemme and used the time to taxi to the end
of 30 to warm up the engine. I wonder, however, about departing 30
shortly after a heavy aircraft has departed on 34. You might very well
intercept his wake somewhere near the intersection of the two runways.

Thanks for the reminder about wake turbulence! It's not much of an
issue at Moriarty, though a few weeks ago, we had a lot of helicopters
working the big fire to the southwest. They were very thoughtful about
their operations and did not impact us other than occupying the man
taxiway on the west end. I think that was a price worth paying!
The heavy on 34 has 1000m to the intersection, you on 30 have 800m. (both measured on google maps, not paying attention to any runway markings)

I'd assume they'd be barely rotating my the intersection, and possibly well after it. You on the other hand are probably a few hundred feet up by then? If so, then no possible problem.

You could always turn right to 000 or beyond as soon as you're off. That should be able to be completed well before the intersection.

--
Dan, 5J
If you take small airplane instruction wake turbulence avoidance is drummed into you. If you haven't had this instruction, because you have a glider license and buy a MG, this may come as a very rude introduction. Basically, you can avoid it by using ONLY the part of the runway that the big guys are on the ground (they need a lot of it, so it shouldn't be hard). Taking off from the numbers, however, can be problematic.

Tom

--
Dan, 5J

Thanks for the great discussion and reminder. I find myself flying a MG this week from a field that has a few jet operations each day, and I'd forgotten about this hazard. Thanks for posting the analysis Uli.

Bret