DC-10 final altitude vs others......

beasly

beasly

Well-Known Member
Hi all,

I am 1.5 miles south and a bit west of (K)ORL and on the final approach path to MCO's 18 Right.

Most days, I have a couple of DC-10's coming in for a landing for Fed-Ex and some other heavies for UPS.

What I have noticed, is that the lighter the jet, the higher their altitude at this point relative to the landing spot.

I just want to run my reasoning for this by you and see what you professionals think.



  1. The lighter jets can have a higher vertical rate of descent before hitting ground effect because ground effect will oppose their descent rate.
  2. the heavier jets need a flatter approach because ground effect is not as big a factor in the big jets?
  3. It is very bad form to bounce a DC-10 five times on the runway like I did in a cessna 172.
Your thoughts?

b.
 
My thoughts are that at 1.5 miles most planes will pass at the same altitude. Could it be that the UPS and FedEx planes are going to a certain ramp---therefore they're always landing on RWY close to that ramp while other aircraft use other RWYS? Maybe there's a displaced threshold?

I think we're all flying roughly the same angle 3 degrees...I don't think the heavies fly a flat approach, they'd end up dragging gear through approach lights and probably wouldn't be "noise friendly" to the neighbors below.

So....My guess is the FedEx planes are landing on a different RWY than the other traffic.
 
Baronman said:
My thoughts are that at 1.5 miles most planes will pass at the same altitude. Could it be that the UPS and FedEx planes are going to a certain ramp---therefore they're always landing on RWY close to that ramp while other aircraft use other RWYS? Maybe there's a displaced threshold?

I think we're all flying roughly the same angle 3 degrees...I don't think the heavies fly a flat approach, they'd end up dragging gear through approach lights and probably wouldn't be "noise friendly" to the neighbors below.

So....My guess is the FedEx planes are landing on a different RWY than the other traffic.
Click to expand...


You could be right, I will give it a closer look now....most of the 737 traffic is on the 17 pair of runways, so my sight picture could be different.

What strikes me is that the very small jets and turbo-props seem to be at least 500 ft higher--sometimes it seems like more (and yes, I am taking into account the relative size of the aircraft)


I will give it some more thought and observe more closely

Thank you!


cordially,

b.
 
Back to BaronMan,

In a small single or twin, I can "chop and drop"...come in high, kill the power, send the props forward, get below Vle, drop the gear, get below Vso , drop the flaps all within 1000 ft of the runway....I would imagine that "chop and drop" does not apply in a DC-10

In the Seminole, you would literally slide forward on the seat as you decelerated, and use the increased rate of descent to your advantage, then when you hit glide-path, give it some throttle and grease it in.

Inertia and momentum would suggest this is not prudent on a DC-10--hence the lower glidepath.

b
 
Lots of guys in smaller machines drop off the glideslope (3deg) as they near the runway. Most airline guys follow it to the touchdown point.

(I say this from observation as a retired airline toad and now gen-av driver)
 
Nope, much higher.

Airtran just came by, at least 500 ft higher.

MCO does have a 3-way (tiered ?) vasi, could that be it?

b.
 
Could it be that the larger airplanes just LOOK to be lower? Same as the larger airplanes LOOK to be slower.

I believe that when landing south at MCO, the typical clearance on a visual approach is to maintain 2500' until south of the ORL VOR.
 
The small planes probably just look farther away due to their relative size. Larger planes also tend to look like they're moving slower. At 1.5mi pretty much everyone's going to be at around 500 feet.
 
Baronman said:
... Could it be that the UPS and FedEx planes are going to a certain ramp---therefore they're always landing on RWY close to that ramp while other aircraft use other RWYS? Maybe there's a displaced threshold?
....
Click to expand...


Yes, and the ramp is maybe 1/3 to 1/2 up the runway. Yes there is a displaced threshold......

So these guys are doing a short field landing? (!!!!!)

hubba hubba!

b .
 
beasly said:
Nope, much higher.

Airtran just came by, at least 500 ft higher.

MCO does have a 3-way (tiered ?) vasi, could that be it?

b.
Click to expand...

That would put Airtran at 1000' and 1.5mi out, a 6 (?) degree glideslope. They'd have the GPWS going off like crazy... Eyes can deceive especially when you have no frame of reference (the sky)
 
TFaudree_ERAU said:
Could it be that the larger airplanes just LOOK to be lower? Same as the larger airplanes LOOK to be slower.

I believe that when landing south at MCO, the typical clearance on a visual approach is to maintain 2500' until south of the ORL VOR.
Click to expand...


Yeah, I thought about that, BUT, to "keep the dream alive" on my days off I will drive around MCO a couple of times, hit the B1B exhibit on Cargo road and time my drive on Cargo road so that I can smell the jet fumes when the jets take off and land (pissing off the people with jobs because I drive the speed limit)

I do not think the perspective is an issue, as the UPS ramp (and Fed Ex) are near a local road and you can see the airplanes up close.


Cordially,

b.
 
E_Dawg said:
The small planes probably just look farther away due to their relative size. Larger planes also tend to look like they're moving slower. At 1.5mi pretty much everyone's going to be at around 500 feet.
Click to expand...

He's 1.5 miles from ORL, not MCO.

Beasly,

Stand 5 feet away from a real train track and tell me how close the train looks when it blows by at 50 mph.

Stand 5 feet away from a model train track and tell me how close the train looks when it blows by at 50 mph (relative to scale).

No different than what you're describing with the airplanes.

Trust me, I went through indoc at ORL for Flight Express. We sat in the hangar on our breaks every day and watched airplanes pass over. I can say without a doubt that they were all at the same altitude regardless of size.
 
beasly...

I used to live under the FAF for 36L at MEM.

During the morning push, MEM gets everything from CRJs to MD-11s.

Due to size, the CRJ always looks higher and faster than the MD-11.
 
TFaudree_ERAU said:
He's 1.5 miles from ORL, not MCO.

Beasly,

Stand 5 feet away from a real train track and tell me how close the train looks when it blows by at 50 mph.

Stand 5 feet away from a model train track and tell me how close the train looks when it blows by at 50 mph (relative to scale).

No different than what you're describing with the airplanes.

Trust me, I went through indoc at ORL for Flight Express. We sat in the hangar on our breaks every day and watched airplanes pass over. I can say without a doubt that they were all at the same altitude regardless of size.
Click to expand...
 
ctab5060X said:
beasly...

I used to live under the FAF for 36L at MEM.

During the morning push, MEM gets everything from CRJs to MD-11s.

Due to size, the CRJ always looks higher and faster than the MD-11.
Click to expand...

I think you are right, but I need to disprove my supposition.

At the hangers at ORL, you don't have the large oak trees I have in my front yard by which to judge relative scale--


Let me think about this a bit.

Thank you ALL! great stuff.


b.
 
What about the 3 bar vasi angle...?

From my AIM, the near and middle bars provide a 3 degree slope while the middle and far bars provide a 4.5 degree slope.

Does anybody use these middle and far bars? Could that account for the lightweights that seem higher?

b.
 
beasly said:
At the hangers at ORL, you don't have the large oak trees I have in my front yard by which to judge relative scale--
Click to expand...

No, but I have been at the controls of a jet aircraft going into MCO landing on 18R on enough occasions to know that they instruct aircraft to maintain 2,500 until south of the ORL VOR. If someone is at a different altitude, they are deviating from their clearance.

beasly said:
What about the 3 bar vasi angle...?

From my AIM, the near and middle bars provide a 3 degree slope while the middle and far bars provide a 4.5 degree slope.

Does anybody use these middle and far bars? Could that account for the lightweights that seem higher?

b.
Click to expand...

You found, read, comprehended and quoted the text from the AIM, but you didn't see the answer to your question?

"Three-bar VASI installations provide two visual glide paths. The lower glide path is provided by the near and middle bars and is normally set at 3 degrees while the upper glide path, provided by the middle and far bars, is normally <sup>1</sup>/<sub>4</sub> degree higher."

I don't know what you're looking for us to say to "disprove [your] supposition". We've all cited practical examples of why we think you may be experiencing an optical illusion, but you continue to doubt us. Aircraft landing on the same runway have absolutely NO reason to be at a different altitude over the same point, regardless of size, parking location, runway configuration, aerodynamics, or anything else.
 
Well, my understanding is that the middle and far bars are designed to compensate for larger aircraft with cockpits higher off the ground, e.g. 747.
 
A few things:
1st- No runway at MCO has a displaced threshold.
2nd- Any plane landing on the 17's will be higher at the point it crosses you view from your yard regardless of the type of plane then any plane landing on the 18's.
3nd If a little guy is landing on 18R behind a heavy he might go a dot high on the ILS but not 500 feet.
 
From the perspective of someone who lives around 19DME off of IADs 1's and a person who flies into Dulles alot it has to do with style of flying.

I know when we come into IAD if we have the airport 30 miles out, they sometimes will clear us for the visual. Some people will set pattern altitude of 1900 feet and hurry on down and at 20 miles out they are at pattern altitude flying along at 250. Then there are the guys that just intercept the glide slope and follow it down.

Basically the guys who get down to pattern normally like to come screaming in at 250 and just pull the power levers to idle a dot below the slope, get it dirtied and then head down. Then the guys that follow glide slope have to manage speed a little better.

This may be how other airlines do it. I know sometimes I see wide bodies at what seems like pattern altitude right above my house. Then when I go to work I see why.
 
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