Citation X on it tail

strangebird

Pre-takeoff checklist
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strangebird
https://www.foxnews.com/weather/hea...s-jet-to-pop-a-wheelie-as-winter-storm-brings


TahoePlane1.jpg
 
bad link.

We had some aircraft do that about a month ago near where I live in Tennessee when some heavy wet snow came through.
 
Looks to me like it's on its wingtips! Lots of sweep on that plane.
 
A couple months ago... (not mine.)
 

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That overnight hangar rate is not looking so high now!
I have never heard of any damage to aircraft after such an event, but those surfaces are not designed with those loads in mind.
Anyone even hear of an inspection procedure?
 
That overnight hangar rate is not looking so high now!
I have never heard of any damage to aircraft after such an event, but those surfaces are not designed with those loads in mind.
Anyone even hear of an inspection procedure?
You don't think those surfaces can take those loads? That's exactly what the horizontal stabilizer does for a living: push down. The wings can easily take it, as well.
 
Well Kenny, I don't think anyone has even weighed 12" (the amounts I witnessed when I was flying in Canada) or more of wet snow, covering the area that the surfaces are - so how can anyone have any idea until that is weighed and compared to air loads in flight?

I think we'd have to actually estimate or weigh it, in order to proclaim damage is not possible.

Also, when I have seen it, the elevator is smashed into the ground (admittedly it is usually not asphalt but is some form and shape of snow)...but still I have seen nor heard of any apparent damage. If there is a control lock on, not good for the cables or the structure, depending on the type of control lock.
 
That overnight hangar rate is not looking so high now!
I have never heard of any damage to aircraft after such an event, but those surfaces are not designed with those loads in mind.
Anyone even hear of an inspection procedure?

The snow loads are distributed loads and airplanes are very adept at handling those. The point loads where the airplane is resting on its aft fuselage or wingtips are the risk. I'd bet a beer at SOS Brothers that airplane gets a very thorough inspection and probably some repairs after that tip-back.
 
Well Kenny, I don't think anyone has even weighed 12" (the amounts I witnessed when I was flying in Canada) or more of wet snow, covering the area that the surfaces are - so how can anyone have any idea until that is weighed and compared to air loads in flight?

I think we'd have to actually estimate or weigh it, in order to proclaim damage is not possible.

I was curious, so some very rough math:
-according to what I could find the horizontal stabilizer of the Citation X has (**at most**) 100 SQ FT of area (looks to actually be much less in reality) .. assuming the heaviest of all possible "snow", pure water, and a depth of 12 inches, IE, 1 foot, that works out to about 62 lbs per square foot.. so with a surface area of 100 SQ FT with 62 lbs per square foot that works out to 6,200 lbs of force. Surely a lot of weight. But with a max takeoff weight of around 36,000 lbs the Citation X is not a small, or light plane.. so even with all that water on there the tail is only carrying 1/6 of the plane's weight.. if you factor in a forward most CG and a steep turn up to the plane's maximum certificated G load of 2.7 then that tail is under a *tremendous* amount of force.. I would bet more than 6,200 lbs. Someone with more time to do the math who has the forward loading limits can graph it out fairly easily of the force actually encountered

You don't think those surfaces can take those loads? That's exactly what the horizontal stabilizer does for a living: push down.
I completely agree. No doubt an inspection will be in order, but I'm quite sure it will be more at the ground contact points and pressure bulkhead.. It was pretty common in Boston when I lived there to come out in the morning after snow and see planes sitting on their tail
 
All of a sudden, everybody wants to be a tail dragger pilot.
 
I was curious, so some very rough math:
-according to what I could find the horizontal stabilizer of the Citation X has (**at most**) 100 SQ FT of area (looks to actually be much less in reality) .. assuming the heaviest of all possible "snow", pure water, and a depth of 12 inches, IE, 1 foot, that works out to about 62 lbs per square foot.. so with a surface area of 100 SQ FT with 62 lbs per square foot that works out to 6,200 lbs of force. Surely a lot of weight. But with a max takeoff weight of around 36,000 lbs the Citation X is not a small, or light plane.. so even with all that water on there the tail is only carrying 1/6 of the plane's weight.. if you factor in a forward most CG and a steep turn up to the plane's maximum certificated G load of 2.7 then that tail is under a *tremendous* amount of force.. I would bet more than 6,200 lbs. Someone with more time to do the math who has the forward loading limits can graph it out fairly easily of the force actually encountered

That snow was fairly wet and heavy, about 15 pcf. Looks like less than a foot at the time, kind of surprising
 
Good that that happened before they got farther along like the sad Atlas Air incident.

There was a Fine Air DC-8 that crashed after taking off from MIA in ‘97. Worked that incident for Lloyds.
 
If you look at a X, with the sweep of it's wings the wingtips are behind the main gear. Combined with the large tail and engines, quite a lot of surface area behind the rear gear. Doesn't take much weight shift to tip back when 90% of the weight is on the mains anyway.
 
I was curious, so some very rough math:
-according to what I could find the horizontal stabilizer of the Citation X has (**at most**) 100 SQ FT of area (looks to actually be much less in reality) .. assuming the heaviest of all possible "snow", pure water, and a depth of 12 inches, IE, 1 foot, that works out to about 62 lbs per square foot.. so with a surface area of 100 SQ FT with 62 lbs per square foot that works out to 6,200 lbs of force. Surely a lot of weight. But with a max takeoff weight of around 36,000 lbs the Citation X is not a small, or light plane.. so even with all that water on there the tail is only carrying 1/6 of the plane's weight.. if you factor in a forward most CG and a steep turn up to the plane's maximum certificated G load of 2.7 then that tail is under a *tremendous* amount of force.. I would bet more than 6,200 lbs. Someone with more time to do the math who has the forward loading limits can graph it out fairly easily of the force actually encountered


I completely agree. No doubt an inspection will be in order, but I'm quite sure it will be more at the ground contact points and pressure bulkhead.. It was pretty common in Boston when I lived there to come out in the morning after snow and see planes sitting on their tail

On jacks --If there is no fuel on it and the interior is out, you cannot work on it without risk of it coming off the nose jack.

I have also heard of a X being towed with no fuel, interior, or ballast tipping over just from being pushed backwards and the tug stopped abruptly. Those massive engines are up high and way aft of the landing gear.

Jacking Global series aircraft, step 1 is install around 1,500 # of nose ballast. The ballast I've used are almost 4k since also jacking it empty with the interior out.

Many Learjets have a kickstand on board, especially with the Raisbeck locker
 
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