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the impossible 180*
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the impossible 180*
by WaiexN143NM » Wed Jun 16, 2021 6:16 pm
Hi all,
Good reading on avweb. article june13 paul boretorelli
the impossible turn reconsidered. good comments at the end of article.
the country is having some warming trends and record heat. watch your density alititude.
engine less pwr, prop and wing not as efficient. a cirrus early model 200hp crashed out of truckee (north side of lake tahoe) yesterday 2 people one fatal. a triQ 2 (O200) crashed on dept out of gila bend az one fatal. DA heat a factor.
regarding the turnbacks to the rwy , its hard to resist. last week out of porterville ca. (south of fresno)
a fresno based F -15 pilot with the 144th air guard wing there, lost his life on dept out of kptv in his RV6.
engine sputtered on dept , a 180* turn attempted and a stall and spin in, and fire.
practice at altitude and set your own minima. try diff bank angles. the nose needs to be agressively pushed down when the pwr is pulled in a climb attitude.
fly safe!
michael.
Good reading on avweb. article june13 paul boretorelli
the impossible turn reconsidered. good comments at the end of article.
the country is having some warming trends and record heat. watch your density alititude.
engine less pwr, prop and wing not as efficient. a cirrus early model 200hp crashed out of truckee (north side of lake tahoe) yesterday 2 people one fatal. a triQ 2 (O200) crashed on dept out of gila bend az one fatal. DA heat a factor.
regarding the turnbacks to the rwy , its hard to resist. last week out of porterville ca. (south of fresno)
a fresno based F -15 pilot with the 144th air guard wing there, lost his life on dept out of kptv in his RV6.
engine sputtered on dept , a 180* turn attempted and a stall and spin in, and fire.
practice at altitude and set your own minima. try diff bank angles. the nose needs to be agressively pushed down when the pwr is pulled in a climb attitude.
fly safe!
michael.
- WaiexN143NM
- Posts: 1194
- Joined: Mon Sep 15, 2014 1:04 am
- Location: SF CA, Tucson AZ, palm springs CA
Re: the impossible 180*
by GraemeSmith » Wed Jun 16, 2021 8:23 pm
From another forum discussing the same article AND the AOPA Air Safety Institute video. Quote a Cessna Pilot and then my response.
^^^^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^^^^^^^
Is a fundamental issue that few discussions about the turn take into account. The EAA are doing a large GA "Crowdsourcing" data project to try and produce a predictor tool to tell you if the turn can be attempted. And Roy encapsulates the main findings so far.
Most GA aircraft have a worse Vg angle of glide than their Vx angle of climb - and thus are not going to make it back to the runway. UNLESS - there is a strong headwind "holding them in" to the environment and so improving the actual angle of climb as you Vx up the wind gradient.
But I am still a proponent of testing and knowing your plane and briefing what you will do in the event of the engine quitting on take off.
Like Joseph Folsom - I could get my 150 around in 500ft - including the "Oh crap" 3 second delay. BUT when I was practicing and if I was being brutally honest - the first one of the day was always nearer an 800ft turn around.
I discovered (after a remark by an Air Force pilot during a webinar on the topic) was that I can hands down get my Sonex around in just 200ft. But rolling her on her back on the edge of a stall and pulling a Spilt S hard to the edge of an accelerated stall - while close to the ground is NOT going to happen in the heat of the moment. It was an interesting exercise. But NOT for real world use.
One thing that came out of the EAA analysis of deaths from turn arounds was that the data could not differentiate between those who got turned around but then pooched the downwind landing and those who stalled during the turn around. I have a suspicion (with no evidence) that quite a lot got turned around OK - but got into trouble on the landing. I can tell you from practice that after you are successfully turned around and are low to the ground - the sight picture of a downwind landing is WAY different that your normal landing. If you turned around in a 10 knot take off headwind you now have a 10 knot tailwind to account for on landing. If you are used to stalling the plane onto the runway at 45KIAS in a 10 knot headwind - you are doing 35knots over the ground. Now downwind a 45KIAS stall with a 10 knot tail wind - you are doing 55 knots over the ground. And the downwind fence is coming up real fast. I have a sneaking suspicion that in trying to "normalize" the sight picture - pilots stalled early and high.
My main takeaway - if you get turned around - it's going to be a FAST landing in terms of ground speed. Fly the ASI to be sure you don't stall prematurely - and don't be afraid to stick it on fast. The idea is to walk away with your life - not necessarily save the plane.
And I don't buy that you have to make the runway. In an urban environment - anywhere inside the fence is often a better bet than outside. Sometimes just a 45 or 90 or 120 degree turn is enough to point somewhere a whole lot better. You need to know your safe minimum maneuvering speed and bank angle and practice nailing those immediately things go wrong. If you know and can perform the MMS - you should be able to avoid the stall spin. In my 150 I used 65 KIAS at 45 degree maximum bank. In the Sonex I use 60KIAS at 45 degree bank. As you are not trying to hold the nose level and are letting it fall through the turn - you don't actually remotely pull 1.4G so the stall speed is actually much lower than a level 45 degree banked turn stall. But you hae to practice this stuff.
So here as an example is my brief for my home airport:
Rwy 04 - straight ahead into the safety area outside the fence. The airport bought that land for a reason. Remember there are power lines at the far end of it. Just go straight ahead.
Rwy 16 - Straight ahead into the nursery or across the road - the vineyard. Remember there are powerlines close in at the main road. Try and get over them. If you are going under - a lot of car drivers will be changing their underwear!
Rwy 22 - 100 degree left into the vineyard. There are NO good options straight ahead and absolutely none to the right. The previous small green patch at 45 right is no longer viable - the Land Trust have filled it with trees and they are now significantly grown. They will shred you.
Rwy 34 - it depends how far into the take off you are. Its a 90 degree left turn into either the field behind the car dealership/the golf course/the graveyard. Straight ahead is not a good option. It's all housing. In a left X-Wind take off on this runway - remember there is also the Rwy 4 safety area to the right as an option.
When arriving at a new to me airport - I always do a quick aerial survey while in the pattern to get an idea of my options for when I depart.
Which is all a long winded way of saying - "it's not that simple".
A Cessna Pilot in another forum wrote:In my 150, the turn is impossible unless there's a good headwind or a very long runway where I could land far from the departure point. The climb rate of my plane in feet per mile is less than the best glide descent rate in feet per mile, so even if I could react instantly and turn in no time with no additional altitude loss I couldn't make it.
^^^^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^^^^^^^
Is a fundamental issue that few discussions about the turn take into account. The EAA are doing a large GA "Crowdsourcing" data project to try and produce a predictor tool to tell you if the turn can be attempted. And Roy encapsulates the main findings so far.
Most GA aircraft have a worse Vg angle of glide than their Vx angle of climb - and thus are not going to make it back to the runway. UNLESS - there is a strong headwind "holding them in" to the environment and so improving the actual angle of climb as you Vx up the wind gradient.
But I am still a proponent of testing and knowing your plane and briefing what you will do in the event of the engine quitting on take off.
Like Joseph Folsom - I could get my 150 around in 500ft - including the "Oh crap" 3 second delay. BUT when I was practicing and if I was being brutally honest - the first one of the day was always nearer an 800ft turn around.
I discovered (after a remark by an Air Force pilot during a webinar on the topic) was that I can hands down get my Sonex around in just 200ft. But rolling her on her back on the edge of a stall and pulling a Spilt S hard to the edge of an accelerated stall - while close to the ground is NOT going to happen in the heat of the moment. It was an interesting exercise. But NOT for real world use.
One thing that came out of the EAA analysis of deaths from turn arounds was that the data could not differentiate between those who got turned around but then pooched the downwind landing and those who stalled during the turn around. I have a suspicion (with no evidence) that quite a lot got turned around OK - but got into trouble on the landing. I can tell you from practice that after you are successfully turned around and are low to the ground - the sight picture of a downwind landing is WAY different that your normal landing. If you turned around in a 10 knot take off headwind you now have a 10 knot tailwind to account for on landing. If you are used to stalling the plane onto the runway at 45KIAS in a 10 knot headwind - you are doing 35knots over the ground. Now downwind a 45KIAS stall with a 10 knot tail wind - you are doing 55 knots over the ground. And the downwind fence is coming up real fast. I have a sneaking suspicion that in trying to "normalize" the sight picture - pilots stalled early and high.
My main takeaway - if you get turned around - it's going to be a FAST landing in terms of ground speed. Fly the ASI to be sure you don't stall prematurely - and don't be afraid to stick it on fast. The idea is to walk away with your life - not necessarily save the plane.
And I don't buy that you have to make the runway. In an urban environment - anywhere inside the fence is often a better bet than outside. Sometimes just a 45 or 90 or 120 degree turn is enough to point somewhere a whole lot better. You need to know your safe minimum maneuvering speed and bank angle and practice nailing those immediately things go wrong. If you know and can perform the MMS - you should be able to avoid the stall spin. In my 150 I used 65 KIAS at 45 degree maximum bank. In the Sonex I use 60KIAS at 45 degree bank. As you are not trying to hold the nose level and are letting it fall through the turn - you don't actually remotely pull 1.4G so the stall speed is actually much lower than a level 45 degree banked turn stall. But you hae to practice this stuff.
So here as an example is my brief for my home airport:
Rwy 04 - straight ahead into the safety area outside the fence. The airport bought that land for a reason. Remember there are power lines at the far end of it. Just go straight ahead.
Rwy 16 - Straight ahead into the nursery or across the road - the vineyard. Remember there are powerlines close in at the main road. Try and get over them. If you are going under - a lot of car drivers will be changing their underwear!
Rwy 22 - 100 degree left into the vineyard. There are NO good options straight ahead and absolutely none to the right. The previous small green patch at 45 right is no longer viable - the Land Trust have filled it with trees and they are now significantly grown. They will shred you.
Rwy 34 - it depends how far into the take off you are. Its a 90 degree left turn into either the field behind the car dealership/the golf course/the graveyard. Straight ahead is not a good option. It's all housing. In a left X-Wind take off on this runway - remember there is also the Rwy 4 safety area to the right as an option.
When arriving at a new to me airport - I always do a quick aerial survey while in the pattern to get an idea of my options for when I depart.
Which is all a long winded way of saying - "it's not that simple".
Graeme JW Smith
-
GraemeSmith - Posts: 939
- Joined: Sat May 18, 2019 8:58 am
- Location: RI
Re: the impossible 180*
by WaiexN143NM » Wed Jun 16, 2021 9:48 pm
Hi Graeme, all,
Thanks for your post. Yes the take away that i got from the avweb article was you may get the plane turned around,
but not make the runway . watch out for approach lites, localizer antennas, and REILS.
fly safe!
michael
Thanks for your post. Yes the take away that i got from the avweb article was you may get the plane turned around,
but not make the runway . watch out for approach lites, localizer antennas, and REILS.
fly safe!
michael
- WaiexN143NM
- Posts: 1194
- Joined: Mon Sep 15, 2014 1:04 am
- Location: SF CA, Tucson AZ, palm springs CA
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