Part 91.117 Speed Restriction

[AC560]

Part 91.117
(d) If the minimum safe speed for any particular operation is greater then the maximum speed prescribed in this section, the aircraft may be operated at this minimum speed.

More a question out of curiosity then anything else to the guys flying the big iron out there but would be some specific instances when minimum safe speed would exceed 250 knots? How would you clear it through ATC? Certainly not a situation I would ever see flying but have always been curious.

 

[PilotSkydiver]

You might want to ask some of the classic drivers... I believe the min safe speed w/o flaps for the 747/100 is like 265 or so and they have an exemption from the faa.. just something I heard hope it helps...

 

[jsingel]

T-38 (US Air Force) had a speed waiver for 300KIAS below 10,000.

 

[Lead Sled]

You might want to ask some of the classic drivers... I believe the min safe speed w/o flaps for the 747/100 is like 265 or so and they have an exemption from the faa.. just something I heard hope it helps...

No waiver was required. There was a thread on the NBAA website several years ago discussing this very subject. (It's only been that last few years that this has even come up for us bizjet types, we haven't had any aircraft where this was even an issue.) Several airline pilots chimed in and contributed to the discussion. The following quote was typical of what they all said: "...If your weight nets a required clean min speed above 250 kts below 10,000' you can accelerate to that speed, period. There is no requirement that you fly with flaps/slats out so you can stay below 250 or 200 kts below the lateral limits of Class B, etc." The bottom line is that the intent of 14 CFR 91.117 is not to force jet aircraft to leave flaps/slats out to climb. They are expected to clean up and fly at clean MMS until 10000'.

For us, the issue was what about when we operate out of one of the airports that are underneath the lateral limits of Class B Airspace where there is a 200 KIAS limit? I was one of the very first pilots to get typed in the Gulfstream G200 back in 2000. The G200, at higher takeoff weights, requires airspeeds of around 220 KIAS to retract the slats and Krueger flaps. Although I believed what the airline pilots were telling us, I also wanted to avoid the opportunity of having to spend "quality time" at the local FSDO so I contacted a good friend of mine who is an FAA inspector. I asked him the following specific question: "...is it necessary to maintain a configuration (slats and Kruger flaps deployed) that will allow the aircraft to comply with the 200 KIAS speed limit when operating beneath the lateral limits of Class B airspace or is it acceptable to fly the aircraft in the "clean" configuration even though the minimum safe airspeed in the clean configuration is above the 200 KIAS limit?" He refered the question to another inspector at another office, who sent me the following reply:

"...The FAR's do not prohibit that operation. Now that I have said that let me explain the finer points about working with ATC and the FAA.
1. If you are at a low altitude and exceed 200 or 250 there is a record made by ATC and ATC may question you. However your flight in question will end up as an
investigation at the FSDO. When you are contacted regarding the "possible fracture" of 91.117 and you tell them what you told me it will probably be closed with no action.

2. You have 2 choices (1) configure the airplane to maintain the speed limits or (2) fly clean at the higher speed.

3. If you maintain speed limits and configure the airplane to do so, no problem end of subject.

4. If you clean the airplane up and accelerate to the speed required be absolutely positive you tell ATC on each frequency you operate on the reasons for exceeding the speed limits while in the airspace discussed in 91.117. Remember ATC spaces aircraft distances based on speed. This should preclude a FSDO investigation.

If you read 91.117(d) it does not specify the aircraft configuration. All it says is "...any particular operation..."

The decision is yours. Hope this helps."

There are those who think that 91.117 (a) authorizes individual air traffic controllers to authorize deviations from the rule. NOT! ATC is NOT the "Administrator" and controllers can not authorize deviations.

There are some other exemptions, such as operational necessity & emergencies that allow you to deviate. Personally, I've deviated from the rule many times, back when I was a Life Flight pilot flying Citations and MU-2 air ambulances. When the flight nurse or physician told us to "step on it" that's exactly what we did. We just told ATC that we needed to keep our speed up. We'd keep the speed at the barber pole until it was necessary to start slowing down for landing. All the FSDO guys wanted from us was the usual deviation letter.

'Sled

 

[atldc9]

I've got to disagree on this one. The POI of my company has been clear, and we have had 2 crews violated from other FSDOs for exceeding the 200 knot restriction below a Class B airspace. The guidance for us is that configure whatever way you need, but you must maintain the speed limit. Just because out clean speed might be 220 doesn't authorize us to use that as our speed limit so that we don't have to stay dirty.

 

[Lead Sled]

I've got to disagree on this one. The POI of my company has been clear, and we have had 2 crews violated from other FSDOs for exceeding the 200 knot restriction below a Class B airspace. The guidance for us is that configure whatever way you need, but you must maintain the speed limit. Just because out clean speed might be 220 doesn't authorize us to use that as our speed limit so that we don't have to stay dirty.

Interesting...

Like I said, there was quite a bit of discussion on this exact topic on the NBAA threads with several contibutions by 121 guys. This together with what I was told by an air carrier inspector. The FAA, you gotta luv 'em. By the way, did the violations hold up? where's JAFI when we need him?

'Sled

 

[mar]

Here's my question

At the risk of self-incrimination...

On departure, how would you even know you're still within the lateral limits of Class B airspace.

I mean, who keeps track of that stuff. Besides I think ATC would rather you just get up and GO and get out of their hair.

And that's what we do and no one has said anything to us.

As for AC560's original question: If we're heavy, when I contact departure I just tell them "we'll require a high speed climb today" just as a sort of courtesy call but I think they're usually expecting it anyway.

 

[atldc9]

I'm not sure if this will work, but I requested and recieved an interpretation of 91.117. I will try to put it below:

U.S. Department Eastern Region 1 Aviation Plaza
of Transportation Office of Regional Counsel Room 561
Jamaica, NY 11434
Federal Aviation Telephone: 718-553-3268
Administration Facsimile: 718-995-5699

Dear Mr.
This responds to your request for an interpretation of § 91.117(d) of the Federal Aviation Regulations (14 CFR). You ask whether that provision would allow for operations in excess of 200 knots indicated airspeed (KIAS) in Class C or D airspace if an aircraft's operational limitations would require a higher speed in a "clean configuration," i.e., when the flaps or slats and gear are retracted. You further inquire whether a higher airspeed would be acceptable if the Class C or D airspace were beneath Class B airspace. We interpret § 91.117(d) as requiring operations at or below 200 KIAS if a normal configuration would allow safe operations at that airspeed, but that Air Traffic Control (ATC) may approve operations at higher speeds if traffic allows.
Section 91.117(b) prohibits operations in excess of 200 knots at or below 2,500 feet above ground level within four nautical miles of the primary airport of a Class C or Class D airspace area that is not within a Class B airspace area, unless otherwise authorized or required by air traffic control. For Class B airspace, the maximum airspeed is 250 knots, as per § 91.117(a). Section 91.117(d) allows operations above the respective 200 or 250 knot limit "if the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section."
The need for the maximum speed provisions in § 91.117 is to allow ATC to provide safe and efficient control services for the mixture of aircraft that maybe operating in the airspace, whether landing, departing, or in transit. To the extent an aircraft has the capability of operating within the prescribed maximum airspeeds, complying with those limits facilitates ATC's handling of all traffic within the designated airspace. The Administrator or ATC may approve operations at higher airspeeds when circumstances can accommodate a deviation without compromising safety. At some airports, environmental concerns may also impact allowing operations at higher airspeeds. Authorization for operations at airspeeds in excess of the limits prescribed in § 91.117 can be sought on a sporadic, per flight basis, or through a waiver pursuant to § 91.905.
Accordingly, we read paragraphs § 91.117(b) and (d) conjointly as prohibiting operations in excess of 200 KIAS within four nautical miles of the primary airport of a Class C or Class D airspace area that is not within a Class B airspace area, for any aircraft that is capable of achieving a configuration for safe operation at 200 KIAS or less. The same prohibition applies in Class C or D airspace underlying the floor of Class B airspace, although the limit increases to 250 knots in Class B airspace. For operations in excess of these limits, to allow for greater efficiency in a clean aircraft configuration, for example, the operator may seek authorization from the controller at the time of operation or, on a broader basis, through a waiver of the maximum limits where justified without compromising safety.
I trust that this response satisfactorily answers your question. Should you require any clarification, please contact Stephen Brice in this office at 718 553-3268, or by e-mail at [email protected].
Sincerely,

Loretta E. Allcalay
Regional Counsel

 

[NoahWerka]

Going into Into SFD one day, Going thru 11,000ft. Daytona Approach specifacily said, "Maintain Present Speed". We were doing 325kts. in the descent above 10,000ft. We asked if we were waived the 250 kt. resriction below 10,000ft. The reply was, " Maintain Present Speed". We questioned the clearance below 10,000 ft. Again, the reply was, "Maintain Present Speed". It being one of those days that it was 3000fr and 2mi. vis., we complied. We still qustioned the controller as to : " Maintain Present Speed". We told him we were doing 325Kts. His reply was, "The sooner I get you out of my airspace, the sooner I can go home"

 

[kevdog]

Going into Into SFD one day, Going thru 11,000ft. Daytona Approach specifacily said, "Maintain Present Speed". We were doing 325kts. in the descent above 10,000ft. We asked if we were waived the 250 kt. resriction below 10,000ft. The reply was, " Maintain Present Speed". We questioned the clearance below 10,000 ft. Again, the reply was, "Maintain Present Speed". It being one of those days that it was 3000fr and 2mi. vis., we complied. We still qustioned the controller as to : " Maintain Present Speed". We told him we were doing 325Kts. His reply was, "The sooner I get you out of my airspace, the sooner I can go home"

I do not believe a controller can waive the 250 restriction below 10,000 in descent. They do the above from time to time though.