91.129, Large-Turbine Aircraft, VASIs, oh my.

C150J

C150J

Well-Known Member
91.129 specifically deals with "Operations in Class D Airspace," but states:

(2) Each pilot operating a large or turbine-powered airplane approaching to land on a runway served by an instrument approach procedure with vertical guidance, if the airplane is so equipped, must:
(i) Operate that airplane at an altitude at or above the glide path between the published final approach fix and the decision altitude (DA), or decision height (DH), as applicable; or
(ii) If compliance with the applicable distance-from-cloud criteria requires glide path interception closer in, operate that airplane at or above the glide path, between the point of interception of glide path and the DA or the DH.
(3) Each pilot operating an airplane approaching to land on a runway served by a visual approach slope indicator must maintain an altitude at or above the glide path until a lower altitude is necessary for a safe landing.

Couple of questions:

1) I can't find this reference in any other reg... can someone prove me wrong? Does your ops manual have similar language? Ours does.

2) Did this used to mention the middle marker as a point at which one could transition to visual cueing?

3) if VASIs generally assure terrain clearance out to 4NM and the GS and VASI aren't coincident, I would argue that an "eyes-outside" approach starting at 4NM in VMC is probably safer than referencing electronic guidance. For example, CLT's ILS to 23 (which is the decommissioned 18C LOC/GS from my understanding) SUCKS. You will go full-deflection yet be right over white... if you follow the GS to DA, you will land nearly outside of the TDZ.


Besides my opinion in question 3, why does it specifically relate to class D operations only? Any insight is greatly appreciated! Thanks guys!

J.
 
Thanks! I definitely agree with you, but it just frustrates me that this isn't a stand-alone reg and is buried in language relating to Class D airspace. Also, according to 2-1-2 in the AIM, we're supposed to have a solid OCS on VASIs from 4NM out (4SM for PAPIs, oddly enough)... I'd rather look outside at this point personally, especially if the two forms of guidance aren't coincident.
 
Just wanted to vent about 91.175 too, which states that we must land in the TDZ as a 121 operator... I'd argue that the CLT ILS 23 won't let you do that if you follow it to DA.
 
C150J said:
Besides my opinion in question 3, why does it specifically relate to class D operations only? Any insight is greatly appreciated! Thanks guys!

J.
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It's not just related to Class D operations only. Look at how the regulations are written. Sometimes they are building blocks on other regulations. Class D operations just happen to be the lowest common denominator between Class B, C, and D operations.

For example:

91.130 Operations in Class C airspace
(a) General. Unless otherwise authorized by ATC, each aircraft operation in Class C airspace must be conducted in compliance with this section and §91.129.

AND

91.131 Operations in Class B airspace
(a) Operating rules. No person may operate an aircraft within a Class B airspace area except in compliance with §91.129 and the following rules:
 
C150J said:
Just wanted to vent about 91.175 too, which states that we must land in the TDZ as a 121 operator... I'd argue that the CLT ILS 23 won't let you do that if you follow it to DA.
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You can also argue that since runway 23 has a VASI that 91.129(3) comes in to play.

(3) Each pilot operating an airplane approaching to land on a runway served by a visual approach slope indicator must maintain an altitude at or above the glide path until a lower altitude is necessary for a safe landing.
Click to expand...
 
C150J said:
Just wanted to vent about 91.175 too, which states that we must land in the TDZ as a 121 operator... I'd argue that the CLT ILS 23 won't let you do that if you follow it to DA.
Click to expand...

Have you checked out FSIMS? I haven't messed with it much but I know that publication is why people must do 2 ILS during recurrent in a jet.
 
Also note that this says "until a lower altitude is necessary for a safe landing." Frankly, I think touching down as early as possible on the runway without undershooting is a good step towards making your landings safer (i.e. more ALD), others will argue with that, for sure, but basically, once it becomes "necessary for safety" you can descend below the VISUAL glideslope. Basically, I say keep it on glideslope until you're at the point where at idle power you'll hit the numbers. That leaves you plenty of margin for error, in smaller machines you also won't nail the lights (can't speak to big airplanes), and its good practice.
 
ppragman said:
(can't speak to big airplanes), and its good practice.
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We predicate our landing data on touching down 1,000 feet from the threshold, so the fixed distance markers are our equivalent to "the numbers." Thanks for all the replies... I never really noticed it, but there is an "OR" in 91.129. Thanks CTAB for pointing out the building-block approach to airspace regs (makes much more sense).
 
ppragman said:
I say keep it on glideslope until you're at the point where at idle power you'll hit the numbers. That leaves you plenty of margin for error, in smaller machines you also won't nail the lights (can't speak to big airplanes), and its good practice.
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Even in a wimpy RJ you'll risk taking out approach lighting if you put it on the numbers.

Our FOM states that if it's available you use the glideslope to the middle marker and then the VASI to the 1000 foot touchdown markings. That said, our former POI (and still one of our FSDO Feds) will beat you with the crash axe if she catches you dropping below the glideslope at ANY point during an approach (even on 23 in CLT).
 
BobDDuck said:
Even in a wimpy RJ you'll risk taking out approach lighting if you put it on the numbers.

Our FOM states that if it's available you use the glideslope to the middle marker and then the VASI to the 1000 foot touchdown markings. That said, our former POI (and still one of our FSDO Feds) will beat you with the crash axe if she catches you dropping below the glideslope at ANY point during an approach (even on 23 in CLT).
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We did it in fighters.......shifting below GS and placing the aimpoint on the threshold on short final to land on the numbers when in VMC. But I agree, thats far and away different from doing it in a large aircraft.
 
BobDDuck said:
That said, our former POI (and still one of our FSDO Feds) will beat you with the crash axe if she catches you dropping below the glideslope at ANY point during an approach (even on 23 in CLT).
Click to expand...

Did some more research. Turns out the reg has changed. It USED to say "middle marker" and "AND" where it says "OR" now, so the new language gives you the flexibility to follow the VASI in. Frustrating about your former POI.
 
C150J said:
Did some more research. Turns out the reg has changed. It USED to say "middle marker" and "AND" where it says "OR" now, so the new language gives you the flexibility to follow the VASI in. Frustrating about your former POI.
Click to expand...

Where did you find that information? If you don't mind me asking.
 
You gotta get creative on 23 in CLT and land before "the hump" or else its a lot of runway sloping away from you the rest of the way.
 
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