Using wing flaps in Class G Airspace

Jaybird180

Jaybird180

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Jaybird180
What's the purpose of this regulation:

Sec. 91.126 — Operating on or in the vicinity of an airport in Class G airspace. said:
(a) General. Unless otherwise authorized or required, each person operating an aircraft on or in the vicinity of an airport in a Class G airspace area must comply with the requirements of this section.


(b) Direction of turns. When approaching to land at an airport without an operating control tower in Class G airspace—
(1) Each pilot of an airplane must make all turns of that airplane to the left unless the airport displays approved light signals or visual markings indicating that turns should be made to the right, in which case the pilot must make all turns to the right; and
(2) Each pilot of a helicopter or a powered parachute must avoid the flow of fixed-wing aircraft.

(c) Flap settings. Except when necessary for training or certification, the pilot in command of a civil turbojet-powered aircraft must use, as a final flap setting, the minimum certificated landing flap setting set forth in the approved performance information in the Airplane Flight Manual for the applicable conditions. However, each pilot in command has the final authority and responsibility for the safe operation of the pilot's airplane, and may use a different flap setting for that airplane if the pilot determines that it is necessary in the interest of safety.

(d) Communications with control towers. Unless otherwise authorized or required by ATC, no person may operate an aircraft to, from, through, or on an airport having an operational control tower unless two-way radio communications are maintained between that aircraft and the control tower. Communications must be established prior to 4 nautical miles from the airport, up to and including 2,500 feet AGL. However, if the aircraft radio fails in flight, the pilot in command may operate that aircraft and land if weather conditions are at or above basic VFR weather minimums, visual contact with the tower is maintained, and a clearance to land is received. If the aircraft radio fails while in flight under IFR, the pilot must comply with §91.185.
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Can anyone share any history on this?
 
Please also note that it appears (to me anyhow) to have been just 'stuck in there' although it is inconsistent in style from the preceeding and proceeding regulations.
 
It is a noise issue. Takes more power to get to the runway with a higher flap setting. All they are trying to do is lessen the noise impact on the neighborhood.
 
bnt83 said:
Noise is a safety issue?
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Yes. Landings become very unsafe when the airport neighbors close the airport because of noise issues. :wink2:

In any event, notice that this only applies to turbojet aircraft, not C-150's, so it doesn't affect many people here, and those that it does should already understand it.
 
Greg Bockelman said:
It is a noise issue. Takes more power to get to the runway with a higher flap setting. All they are trying to do is lessen the noise impact on the neighborhood.
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Maybe with a 195, but not anything with modern flaps...:D If they really work to enhance lift at lower airspeeds, you can land power-out with full flaps.
And how and why would they issue a blanket noise-abatement procedure for any and every airport lying within or near Class G airspace?

It's bizarre, but my guess is it's a response to some statistic for flap-related accidents... probably more to do with attempted go-arounds from short runways with tall obstructions; probably mostly high-elevation airports.
 
Ron Levy said:
In any event, notice that this only applies to turbojet aircraft, not C-150's, so it doesn't affect many people here, and those that it does should already understand it.
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Woops, I didn't see that on the first read... so is it a noise thing? Do jets need more power to maintain desired descent rate/angle with full flaps? Or am I right that it has to do with flap-related mishaps?
 
Greg Bockelman said:
It is a noise issue. Takes more power to get to the runway with a higher flap setting. All they are trying to do is lessen the noise impact on the neighborhood.
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This....it is why alot of the ancient jets (DC-8s for example) are prohibted from using max flap settings unless in an emergency.
 
rottydaddy said:
Woops, I didn't see that on the first read... so is it a noise thing? Do jets need more power to maintain desired descent rate/angle with full flaps? Or am I right that it has to do with flap-related mishaps?
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Every airplane needs more power to maintain a fixed angle of descent with more flaps.

And every airplane will hang around at low altitude longer in a go-around with the flaps hanging down full. Go-arounds are where the real noise gets made. Especially with jets.
 
rottydaddy said:
Woops, I didn't see that on the first read... so is it a noise thing?
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Yes.
Do jets need more power to maintain desired descent rate/angle with full flaps?
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Yes -- just like props, but when they power up that much, it gets way noisier than when I do that in my Tiger.

Or am I right that it has to do with flap-related mishaps?
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Nope - but a good guess anyway, the way the FAA thinks.
 
MAKG1 said:
Every airplane needs more power to maintain a fixed angle of descent with more flaps.

And every airplane will hang around at low altitude longer in a go-around with the flaps hanging down full. Go-arounds are where the real noise gets made. Especially with jets.
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I'll say it again, how is noise a safety issue? A pilot of a commercial flight will ignore procedures that specifies flaps because of noise abatement? Riiiiihhhhggggtttttt :rolleyes:
 
rottydaddy said:
Do jets need more power to maintain desired descent rate/angle with full flaps? Or am I right that it has to do with flap-related mishaps?
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Nothing to do with mishaps and everything to do with jets...especially the older jets of the 50s and 60s. When you pull the power way back to idle or close to idle, the time it takes to spin back up and respond can take quite a bit longer than a prop. The early jets were notorious for this (for example the Air Cal 737 that geared up at SNA back in the 80s on a botched go-around).

The solution is to add drag (flaps) so that you can keep the power up and thus your engines are ready to give you what you need, when you need it. The DC-8s for example had flap settings of 40 or 50 degrees for this reason.....problem is that with that amount of drag, the engines are...well, very loud.

So basically the FAR is saying.....be a good neighbor and use the minimum you need to safely land the airplane....but at the same time leaving the PIC with the final authority to use as much as needed to safely operate the aircraft.
 
bnt83 said:
I'll say it again, how is noise a safety issue? A pilot of a commercial flight will ignore procedures that specifies flaps because of noise abatement? Riiiiihhhhggggtttttt :rolleyes:
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Did someone say it's a safety issue?
 
Palmpilot said:
Did someone say it's a safety issue?
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see here

Greg Bockelman said:
It is a noise issue. Takes more power to get to the runway with a higher flap setting. All they are trying to do is lessen the noise impact on the neighborhood.
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However, each pilot in command has the final authority and responsibility for the safe operation of the pilot's airplane, and may use a different flap setting for that airplane if the pilot determines that it is necessary in the interest of safety

Implying that using a different flap setting in the interest of safety is related to noise in this thread, which I find incorrect.
 
rottydaddy said:
Woops, I didn't see that on the first read... so is it a noise thing? Do jets need more power to maintain desired descent rate/angle with full flaps? Or am I right that it has to do with flap-related mishaps?
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See Post #4.
 
Fearless Tower said:
So basically the FAR is saying.....be a good neighbor and use the minimum you need to safely land the airplane....but at the same time leaving the PIC with the final authority to use as much as needed to safely operate the aircraft.
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I think that accurately sums up the situation.

Remember that the FAA's mission includes both safety and the promotion of aviation, and if noise issues which could have been mitigated safely lead (even indirectly) to the closure of airports, that is contrary to the promotion side of their mission.
 
bnt83 said:
Noise is a safety issue?
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Who said it was a safety thing? Read it again. It says that the PIC is responsible for the safety of the flight, and if more flaps are necessary to operate safely, then the PIC is within his rights to use them.

But the issue is one of noise.
 
Greg Bockelman said:
Who said it was a safety thing? Read it again. It says that the PIC is responsible for the safety of the flight, and if more flaps are necessary to operate safely, then the PIC is within his rights to use them.

But the issue is one of noise.
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Ok I'll buy that. But everyone here is focused on the approach and approach flap setting which seems backwards.
 
Except that most of the noisy ones are gone and the new engines are turbo-fans.
MAKG1 said:
It can be. It won't kill you (usually), but it can injure you to the point of permanent disability. Fairly easily when considering turbojets.
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MAKG1 said:
Yup, and the reg specifically calls out turbojets. Not turbines as appear elsewhere.
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For regulatory purposes, "turbojets" includes turbofans but not turboprops. So, the reg under discussion applies to aircraft with turbofan engines, not just those with pure turbojets.
 
Late to the party, but yes, it's all about noise. Smaller flap settings require less power. That generates less noise. The big but is that I can use a greater flap setting if I feel it's required for safety.
 
The reg contradicts its self. It tells you to use minimum flaps per landing configuration yet gives the PIC final authority to do whatever the hell he/she wants. It is rare we can go into a class G airport with less than full flaps just due to the nature of the airport. The Lear QRH actually gives DB levels for different flap settings and weights. Because of airports like LGB that have DB level curfews that we have to comply with, this is a great help. I will see if I can upload a picture of it so you guys can see.
 
jonnyjetprop said:
Late to the party, but yes, it's all about noise. Smaller flap settings require less power. That generates less noise. The big but is that I can use a greater flap setting if I feel it's required for safety.
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You might do that to keep the engines spooled up, if you were concerned about the possibility of wind shear etc...
 
You never, ever spool down the engines until in the flair in jets. It is a major criterion for what constitutes a stabilized approach. High bypass turbofans aren't as critical as the old straight pipe engines, but it still takes time to spool things up.

dell30rb said:
You might do that to keep the engines spooled up, if you were concerned about the possibility of wind shear etc...
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What I don't understand, assuming all the above is true about noise and such, why is this only applicable to airports in Class G? What about E? Or C/B?

It just seems kind of out-of-place.
 
jonnyjetprop said:
You never, ever spool down the engines until in the flair in jets. It is a major criterion for what constitutes a stabilized approach. High bypass turbofans aren't as critical as the old straight pipe engines, but it still takes time to spool things up.
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To clarify I meant... spooled up more :)

Takes a higher power setting to achieve the same glideslope with more flaps out.
 
RussR said:
What I don't understand, assuming all the above is true about noise and such, why is this only applicable to airports in Class G? What about E? Or C/B?

It just seems kind of out-of-place.
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See:

14 CFR 91.127(a)
14 CFR 91.129(a)
14 CFR 91.130(a)
14 CFR 91.131(a)

If it applies to Class G airports, it applies to every airport.
 
So Thurmond Munson was killed from landing at controlled airport.
 
mikea said:
So Thurmond Munson was killed from landing at controlled airport.
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???

What does forgetting to extend the flaps have to do with this?

NTSB said:
The National Transportation Safety Board determines that the probable cause of the accident was the pilot's failure to recognize the need for, and to take action to maintain, sufficient airspeed to prevent a stall into the ground during an attempted landing. The pilot also failed to recognize the need for timely and sufficient power application to prevent the stall during an approach conducted inadvertently without flaps extended. Contributing to the pilot's inability to recognize the problem and to take proper action was his failure to use the appropriate checklist and his nonstandard pattern procedures which resulted in an abnormal approach profile.
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Besides, I don't believe the current FAR (as written) applied back in 1979.​
 
An old friend replied off list: "Since they leave it up to me, I think I'll stick with whatever flap setting gives me the slowest possible groundspeed at landing."

He flies and has flown stuff this rule would apply to. Unless the airport has noise monitoring and an overriding rule/penalty, I'd have to say I agree.

If fate has decided you're going to have a bad day and hit something on the ground, might as well hit it slower. Screw the noise.
 
"NO motorist shall ever exceed the speed of 65 Miles Per Hour, except that motorists can drive as fast as they determine is safe"

Super rule Cletus.
 
Captain said:
"NO motorist shall ever exceed the speed of 65 Miles Per Hour, except that motorists can drive as fast as they determine is safe"

Super rule Cletus.
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That might actually be relevant if cars had an MCA or stall speed subject to gusts.
 
It's the spirit of the rule that I was commenting on. I'll try again;

"No employee shall drink Cokes at work, except that any employee may drink a Coke if they want."
 
Captain said:
It's the spirit of the rule that I was commenting on. I'll try again;

"No employee shall drink Cokes at work, except that any employee may drink a Coke if they want."
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So, now want = safe?

Still not equivalent. There are no safety situations that require a Coke, though there are some that preclude that.

The point of the exception is obviously to avoid prohibiting safety. You would prefer the reg would prohibit flaps at a short field that requires it? A determination of safety does not free you from consequences. Like busting Class B avoiding a midair is a textbook use for 91.3(b), but you may have to justify the decision afterward.
 
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