250 Below 10

[big pimpn']

On the whale, we have to accelerate to 280 plus on heavy takeoffs due to operational necessity. Otherwise we would have to leave our flaps down through 10k which is ludicrous. We’ve been doing this for many years and this has never been an issue.

(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.

 

[PBRstreetgang]

Thanks for the info and ref to the reg's. Does anyone know if military controllers have 'permission' from the administrator to waive speed restrictions? much like the those restrictions are removed in MOA's/restricted areas and specific low level routes? thanks again.

"Public use", (military) aircraft are exempt from the FARs. Compliance is usually built into their SOP, they don't get violated by the FAA, just "THE BOSS".
PBR

 

[Lrjtcaptain]

We authorize heavies all the time to exceed the 250kt rule in Class B. Get a B747-400 to RJAA without doing a 280KT climb...good luck. We authorize it all day every day.

 

[AC560]

"Public use", (military) aircraft are exempt from the FARs. Compliance is usually built into their SOP, they don't get violated by the FAA, just "THE BOSS".
PBR

"(Exemption to Federal Air Regulations 91.177 issued to DOD, May 18, 1978)-Operations below 10,000 feet Mean Sea Level at Indicated Air Speed in excess of 250 knots, in noncompliance with Federal Air Regulations 91.117 (a), are authorized for military aircraft, including Reserve and Air National Guard components, only under the following conditions:...

"g. If the airspeed required or recommended in the airplane flight manual to maintain safe maneuverability is greater than the maximum speed described in Federal Air regulations 91.117, the airplane may be operated at that speed."

I believe there was a case a couple years ago where 2 guys at an airshow lost their civilian certificates for a 91.117 violation.

We authorize heavies all the time to exceed the 250kt rule in Class B. Get a B747-400 to RJAA without doing a 280KT climb...good luck. We authorize it all day every day.

So you say to a 744 on departure going to RJAA "Fly 280kts heading 360" or does the pilot advise you that is what he is doing. My understanding has always been the requirement is for the pilot to advise per AIM 4-4-12 there is no authorization from ATC. If you have this authority what was the logic for the IAH high speed departure test a couple years back?

 

[westwind driver]

(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.

How about an MD-80? 747?

You do not have to put flaps out to follow the rule as indicated above. A heavy 737 can't slow to 200 and keep the flaps up, so you don't have to when flying under Class B. Just fly the minimum clean speed. An MD-80 taking off heavy will need about 260 knots clean maneuver speed. Only a dolt would leave the flaps out to comply with the 250 rule in that case.

Where do you get your numbers?

MD80 series (reference the -83 here) If you look at the charts, assuming MGTOW of 149,500#, using the 150,000# chart, 33 degress C at sea level, Altimeter 30.06, dry runway, no wind, Flaps 15

Here are your speeds:

V1: 143
VR: 147
V2: 154
Flap Retract: 169
Slat Retract: 202
Final Segment: 223
Clean Maneuver: 252

The airplane will fly just fine cleaned up at 250 and climb no problem. Once you hit 10k push the nose over for a 300-320kt climb.

I don't think the Maddog is like a true heavy that has to have the slats out up till around 280. Comming out of Charlotte, ATC has to cancel a 280 speed restriction.

As for the 250/10k rule, well... Been into North Dakota airports and had controllers tell us no speed restriction below 10,000, and this was on the descent. Ultimately, if this question went to court, I would think the PIC is required to adhere to FAR/AIM regardless of what ATC tells you. Just MHO.

 

[westwind driver]

Interesting ASRS report here:

http://asrs.arc.nasa.gov/docs/cb/cb_249.pdf

 

[Singlecoil]

Where do you get your numbers?

MD80 series (reference the -83 here) If you look at the charts, assuming MGTOW of 149,500#, using the 150,000# chart, 33 degress C at sea level, Altimeter 30.06, dry runway, no wind, Flaps 15

Here are your speeds:

V1: 143
VR: 147
V2: 154
Flap Retract: 169
Slat Retract: 202
Final Segment: 223
Clean Maneuver: 252

The airplane will fly just fine cleaned up at 250 and climb no problem. Once you hit 10k push the nose over for a 300-320kt climb.

I don't think the Maddog is like a true heavy that has to have the slats out up till around 280. Comming out of Charlotte, ATC has to cancel a 280 speed restriction.

As for the 250/10k rule, well... Been into North Dakota airports and had controllers tell us no speed restriction below 10,000, and this was on the descent. Ultimately, if this question went to court, I would think the PIC is required to adhere to FAR/AIM regardless of what ATC tells you. Just MHO.

I get my numbers from memory from over 4 years ago, so I'm not surprised if they aren't super accurate. I do remember that the clean maneuver speed was sometimes over 250 knots, so section d of the FAR's applied. The point is, you are allowed to fly 252 knots in your example.

 

[westwind driver]

I get my numbers from memory from over 4 years ago, so I'm not surprised if they aren't super accurate. I do remember that the clean maneuver speed was sometimes over 250 knots, so section d of the FAR's applied. The point is, you are allowed to fly 252 knots in your example.

Pretty good memory to be that close Of course you would probably agree most aircraft of the MD80 size are pretty close in numbers?

I went back a read my post, and sorry if it sounded a$$holish. Didn't mean to come across like that. I was more though questioning if slat retract speed is say, 200 kts, and clean maneuver speed is say 250 kts, what is there to say that you couldn't fly at 230 kts. Not that you would, but can you?

I have performance charts for several aircraft I do not fly, and have never flown. So my experience with this is somewhat new.

If someone could explain why pilots want to fly at clean maneuvering speed (other than having to keep slats/flaps extended) maybe I could get a better understanding.

My experience has been limited to V2+20 flaps up, climb at 250/.65

Does any of this have to do with say exceeding 15 degrees bank flaps/slats retracted? Because of VSL?

Good discussion here I think.

 

[stupidpilot]

CMS(Clean Maneuvering Speed) allows the aircraft to meet the final segment climb gradient. If you lose an engine the extra drag could really hurt your performance and get you in a whole lot of trouble.

 

[milky]

As a military pointy nose pilot, you are expected to operate at a speed that is reasonable for maneuverability and visibility over the nose. For the Hornet, 300-350 knots is defensible. It is true that we cannot be violated by the FAA. Only by the CNO.

 

[Singlecoil]

Pretty good memory to be that close Of course you would probably agree most aircraft of the MD80 size are pretty close in numbers?

I went back a read my post, and sorry if it sounded a$$holish. Didn't mean to come across like that. I was more though questioning if slat retract speed is say, 200 kts, and clean maneuver speed is say 250 kts, what is there to say that you couldn't fly at 230 kts. Not that you would, but can you?

I have performance charts for several aircraft I do not fly, and have never flown. So my experience with this is somewhat new.

If someone could explain why pilots want to fly at clean maneuvering speed (other than having to keep slats/flaps extended) maybe I could get a better understanding.

My experience has been limited to V2+20 flaps up, climb at 250/.65

Does any of this have to do with say exceeding 15 degrees bank flaps/slats retracted? Because of VSL?

Good discussion here I think.

No worries, mate
In the MD you were limited to 15 degrees of bank until you reached clean maneuver speed, so yes you could fly 230 clean.
Also, have you ever noticed that the flap retraction speeds on takeoff (when you are heavy) are lower than the flap extension speeds when you are landing and lighter? In a 737 you are retracting the flaps at about 190 heavy, then 3 hours later you have to extend the first notch before 200 or so. So yes, you can definitely fly slower than the published speeds. In the 737NG, the flap extension speed might be 200, but you are good to 40 degrees of bank (25 plus a 15 degree overshoot) to the top of the yellow arc, which is much slower.

 

[GCD]

The IAH Class B high speed climb experiment was contested by ALPA for a safety issue. Most bird strikes occur below 10,000' and most windscreens are tested and certified for bird strikes at 250 KIAS or less.

The B747, however, has a three inch thick windscreen because of the operational need to climb clean at 278 KIAS during the final segment climb, which is well below 10,000'.

 

[GittinFatter]

Some of you folks are only thinking about desending and some are only thinking about climbing. Both groups need to think about both climbing and decending to carry on an intelligent argument.
A 747 that is carrying any weight at all will usually have a clean speed above 250 on T/O. A max gross clean speed will be about 280kts on take-off. I have had controllers waive the Speed when they want an altitude first on a desent. Controllers are a represenative of the "administrator".

 

[Say Again Over]

We authorize heavies all the time

Sorry MK you don't have the authority to waive this regulation, the PIC does by applying the reg.

 

[ultrarunner]

Where do you get your numbers?

MD80 series (reference the -83 here) If you look at the charts, assuming MGTOW of 149,500#, using the 150,000# chart, 33 degress C at sea level, Altimeter 30.06, dry runway, no wind, Flaps 15

Here are your speeds:

V1: 143
VR: 147
V2: 154
Flap Retract: 169
Slat Retract: 202
Final Segment: 223
Clean Maneuver: 252

On the -80's the faster speeds down low after takeoff are typically in a -88 version with forward and aft aux tanks. With these, and loaded for LAX or SFO or SEA you'd approach 170,000 lbs for take-off, if I recall.