91.117 - Aircraft Speed

S

skyhigh600

New Member
Sec. 91.117 - Aircraft speed.
(a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).
(b) Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots (230 mph.). This paragraph (b) does not apply to any operations within a Class B airspace area. Such operations shall comply with paragraph (a) of this section.
(c) No person may operate an aircraft in the airspace underlying a Class B airspace area designated for an airport or in a VFR corridor designated through such a Class B airspace area, at an indicated airspeed of more than 200 knots (230 mph). (d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.


Two questions
(1) Realizing that ATC is not the administrator/faa, when can or would 250kts below 10,000 ft ever be authorized (in US airspace for this argument)? How would it be authorized? I've been told that Houston Tracon has been waiving this speed limit for years now...do they have an LOA or something of the sort from the FAA?

(2) I have been told specifically by an FAA inspector (when asked) :bandit:that ATC can waive the 250kt speed limit below 10,000 ft when in class B airspace. I didn't buy it, and when I pointed to the language in the regs for 91.117(a), "...by the administrator..." he said that ATC was "...delegated authority..." [FAR 1] by the FAA, and thus could waive it in their airspace?

Referring to AIM 4-4-12(h):
Pilots are reminded that they are responsible for rejecting the application of speed adjustment by ATC if, in their opinion, it will cause them to exceed the maximum indicated airspeed prescribed by 14 CFR 91.117(a),(c), and (d).

Note the absence of reference to 91.117(b) where the language is "...unless otherwise authorized or required by ATC...".

Wrapping this all up...is there some specific reg that trumps all the above saying ATC can wavie 250kts under 10,000 ft that I am missing here??? :panic:

Thanks!!
 
1) that was a test, I'm 99% sure they don't do it anymore
2) from what I picked up, ATC may ask you to fly faster but it is up to the pilot to obey the FAR's
 
The Houston thing was a test and they canceled it. The only time you can go faster than 250 knots below 10K is if it is an emergency and it requires it or if for some crazy reason your flying below 250 knots would adversely affect the safe outcome of the flight. You will have some splaining to do in both those scenarios though. I think military training routes can do more than 250 below ten but they obviously have the permission of the "administrator" or whatever they call it. ATC can never cancel a speed restriction or any FAR for that matter...
 
Well, there are exceptions to every rule.

I can only speak to the 747, but I'm sure other heavies are in the same boat.

Once we clean up, even at light weights, we accelerate above 250, or it'll fall out of the sky.

Of course, we ask ATC for a "high speed climb", but we might be doing anything from 251 up to around 300. Again weight dependant.
 
If'n you're outside of US airspace, it ain't a law (sorta ...12 miles offshore, e.g. East Coast routes). More importantly, bring on the gambling and fireworks!!
 
As was mentioned, some airplanes can't fly below 250kts clean. One that comes to mind is the T-38, and no, they're not all military.

I'm sure waivers are issued for airshows as well.
 
Polar742 said:
Well, there are exceptions to every rule.

I can only speak to the 747, but I'm sure other heavies are in the same boat.

Once we clean up, even at light weights, we accelerate above 250, or it'll fall out of the sky.

Of course, we ask ATC for a "high speed climb", but we might be doing anything from 251 up to around 300. Again weight dependent.
Click to expand...

I am sure ATC looks the other way more often than not. ;)
 
It always struck me as backwards. Why can't ATC waive the restriction. In every other country, they can do it. Why not in the US. I believe Concorde (RIP) used to get it regularly, and I believe that for any other aircraft, (usually heavy) the crew simply needs to advise ATC of the min clean speed.
 
We do it all the time. Typically our clean speed with slats retracted is well above 250kts if we're heavy. We'll notify ATC, but of course don't need specific permission to accelerate beyong 250 since the regs already allow us.
 
Here is the letter granting speed limit exemption to the DoD (at least, the first page of it. I used to have both pages but I can't find the second one right now). I'm sure there is a more current letter than this, especially given the airspace re-organization in the mid 90s, but I don't have a copy of it.

FAAspeedauthorization.jpg
 
Polar742 said:
Well, there are exceptions to every rule.

I can only speak to the 747, but I'm sure other heavies are in the same boat.

Once we clean up, even at light weights, we accelerate above 250, or it'll fall out of the sky.

Of course, we ask ATC for a "high speed climb", but we might be doing anything from 251 up to around 300. Again weight dependant.
Click to expand...

MD-11 needs to fly even faster than the 747s. Max TOGW clean MMS is 289kts.
 
skyhigh600 said:
Sec. 91.117 - Aircraft speed.
(a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).
(b) Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots (230 mph.). This paragraph (b) does not apply to any operations within a Class B airspace area. Such operations shall comply with paragraph (a) of this section.
(c) No person may operate an aircraft in the airspace underlying a Class B airspace area designated for an airport or in a VFR corridor designated through such a Class B airspace area, at an indicated airspeed of more than 200 knots (230 mph). (d) If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.


Two questions
(1) Realizing that ATC is not the administrator/faa, when can or would 250kts below 10,000 ft ever be authorized (in US airspace for this argument)? How would it be authorized? I've been told that Houston Tracon has been waiving this speed limit for years now...do they have an LOA or something of the sort from the FAA?

(2) I have been told specifically by an FAA inspector (when asked) :bandit:that ATC can waive the 250kt speed limit below 10,000 ft when in class B airspace. I didn't buy it, and when I pointed to the language in the regs for 91.117(a), "...by the administrator..." he said that ATC was "...delegated authority..." [FAR 1] by the FAA, and thus could waive it in their airspace?

Referring to AIM 4-4-12(h):
Pilots are reminded that they are responsible for rejecting the application of speed adjustment by ATC if, in their opinion, it will cause them to exceed the maximum indicated airspeed prescribed by 14 CFR 91.117(a),(c), and (d). Thats your answer, the regs do not give you the authority to fly above 250kts under 10000 (except for paragraph 91.117 (d) )
Note the absence of reference to 91.117(b) where the language is "...unless otherwise authorized or required by ATC...". Go back and re-read the full paragraph, its not talking about the 250kt below 10000 rule
Wrapping this all up...is there some specific reg that trumps all the above saying ATC can wavie 250kts under 10,000 ft that I am missing here??? :panic: NO

Thanks!!
Click to expand...

The test program in Houston ended in 2004. To be safe the only thing you can do is follow the regs. ATC will help you violate yourself in a heart beat!

I just read a story of a guy while on an ils broke out at 800 had a visual on the runways offered to cancel ifr and side step to a parallel runway to allow for faster traffic coming in behind him! Nice guy! But the A##@%*^e FAA inspector who heard this Violated the pilot for flying VFR in IMC condition! 800 foot cieling! ATC "approved" it

91.117 (d) if the minimum safe airspeed for a particular operation is greater then the maximum speed prescribed in this section, the aircraft may be operated at THAT minimum airspeed!
 
Chief Captain said:
Why can't ATC waive the restriction.
Click to expand...

To answer that question you must consider the reason for the 250kt speed limit.

The limit applies below 10,000' where the VFR visibility and cloud clearance requirements are lower. Above 10,000', where fast airplanes are going fast, VFR aircraft need greater visibility and must stay farther away from clouds. This allows for more time to see and avoid fast IFR airplanes as they come out of clouds or approach through the haze.

Within the 4nm/2500' 200kt speed limit area around an operating control tower, all aircraft are required to be in radio contact with the controller so the controller can base his authorization to exceed the 200kt limit on known traffic. Below 10,000' there is no such requirement for ATC communication so the controller can't replace the collision avoidance value of limiting speed to 250kts.

Within a Class B area the controllers do have the ability, and requirement, to separate airplanes which is why they were able to do the >250kt test. I don't know why they didn't continue or expand the procedure.
 
You must log in or register to reply here.
Back
Top