Which speed keeps ATC happy?

Center_Mid · May 21st, 2007, 11:59

Over the weekend, I was flying my club's 172 on the 13R ILS into Boeing Field in Seattle. I'm about four miles from the outer marker and the controller asks me what max speed I could maintain for spacing. I look at my airspeed and power configuration and quickly estimate that I could maintain 120 KIAS. So, I respond with 120. However, as the approach continues, I notice my groundspeed on the GPS is showing around 110-113 knots. No matter what I did power-wise, I would get 120-125 indicated but never more than 113 over the ground.

I had a Caravan, a Lear, and another 172 behind me on the ILS. I heard ATC slow the Caravan down for me and I would guess the Lear had to slow, too. I felt a little bad about clogging the pipeline, especially since it was just a practice ILS in VFR conditions.

My question is: next time, should I estimate what groundspeed I could maintain or stick with indicated?

TFaudree_ERAU · May 21st, 2007, 12:05

The controller works with ground speed. But...remember that all those airplanes behind you on approach are experiencing the same headwind you are. If you are told to maintain 120 KIAS and the wind is holding you at 113 ground speed, then the Lear behind you is doing 160 KIAS and 153 across the ground. Seven knots is seven knots. Stick to indicated.

BajtheJino · May 21st, 2007, 12:08

Indicated.

Cessnaflyer · May 21st, 2007, 12:27

What club are you in, in Seattle?

GaTechKid · May 21st, 2007, 13:50

Indicated

Center_Mid · May 21st, 2007, 13:56

I'm at Galvin.

SteveC · May 21st, 2007, 14:24

ATC will always talk to pilots with regard to indicated speed, not groud speed. Same with headings versus ground track. Fly the headings and indicated speeds that they give you and let them worry about correction for the winds. They're (usually) pretty good at it.

DE727UPS · May 21st, 2007, 14:41

I used to go to Bremerton a lot for the ILS rather than mix it up at BFI. You really wanna get some attention. Try holding at NOLLA at 2000 feet...just to exercise your right to be there. You're outside the B and outside BFI's D, just barely...

Center_Mid · May 21st, 2007, 14:55

Quote:

Originally Posted by DE727UPS

I used to go to Bremerton a lot for the ILS rather than mix it up at BFI. You really wanna get some attention. Try holding at NOLLA at 2000 feet...just to exercise your right to be there. You're outside the B and outside BFI's D, just barely...

Hehe, that'd be a good way to get to know everyone up close 'n personal.

Cessnaflyer · May 21st, 2007, 15:20

Quote:

Originally Posted by Center_Mid

I'm at Galvin.

Galvin has a club now?

Center_Mid · May 21st, 2007, 16:13

Quote:

Originally Posted by Cessnaflyer

Galvin has a club now?

Sort of. You pay a membership fee and get a discount off the retail hourly rate. That's about it. It's not a "club" in the social sense.

surreal1221 · May 21st, 2007, 17:57

Whatever speed keeps you from generating a CA on the scope. . .

Cessnaflyer · May 21st, 2007, 22:14

Quote:

Originally Posted by Center_Mid

Sort of. You pay a membership fee and get a discount off the retail hourly rate. That's about it. It's not a "club" in the social sense.

Same thing as when I used to rent from there.

Do they provide any lube for you when you pay for their aircraft?

Center_Mid · May 22nd, 2007, 03:27

Quote:

Originally Posted by Cessnaflyer

Same thing as when I used to rent from there.

Do they provide any lube for you when you pay for their aircraft?

I just put it on the Underhills' bill.

Doug Taylor · May 22nd, 2007, 03:40

Quote:

Originally Posted by Center_Mid

I just put it on the Underhills' bill.

Me too, they're going to be so pissed!

Cav · May 22nd, 2007, 08:37

Quote:

Originally Posted by Center_Mid

I just put it on the Underhills' bill.

You wrang?

DE727UPS · May 22nd, 2007, 13:22

I'll have the steak sandwich and.....the steak sandwich.

Cessnaflyer · May 22nd, 2007, 19:09

Quote:

Originally Posted by Center_Mid

I just put it on the Underhills' bill.

Haha well they sell enough wood things to pay for it

PurduePilot · May 22nd, 2007, 22:32

Which speed makes ATC happy?

... the one that keeps you in the air!

TonyWilliams · May 22nd, 2007, 23:25

Indicated or Mach speed

Matt777 · May 23rd, 2007, 06:00

Quote:

Originally Posted by Center_Mid

Sort of. You pay a membership fee and get a discount off the retail hourly rate. That's about it. It's not a "club" in the social sense.

I guess you've never been there at midnight when the secret flying club meets. :P

If you felt really bad about slowing everyone down on the ILS you could just ask to sidestep to 13L and cancel... remember to brace for the wake turbulence though if it's a 75 or a heavy (I'm sure you know the 747 LCF story).

jtrain609 · May 23rd, 2007, 11:00

Quote:

Originally Posted by TonyWilliams

Indicated or Mach speed

That's a lie and you know it

ATC: Amflight 8031 maintain best forward speed
Amflight: Ok sir, we're at it right now
*Our Chieftain starts and descent, thus speeding up from 120 to 180*
ATC: Amflight 8031 why are you speeding up, you said that was your best forward speed! Slow to 120
Amflight: Sorry sir, we can go down, or we can slow down, but not both.
ATC: Amflight 8031 turn right 330 I'm going to have to spin you

It doesn't matter what we do, we piss you guys off!

Center_Mid · May 23rd, 2007, 11:40

Quote:

Originally Posted by Matt777

If you felt really bad about slowing everyone down on the ILS you could just ask to sidestep to 13L and cancel... remember to brace for the wake turbulence though if it's a 75 or a heavy (I'm sure you know the 747 LCF story).

As soon as I got on with tower I tried that, but there was multiple traffic for 13L, too. Busy day.

TonyWilliams · May 23rd, 2007, 18:45

Quote:

Originally Posted by jtrain609

That's a lie and you know it

It doesn't matter what we do, we piss you guys off!

Well, ya gotta be sure what their asking, and we gotta be sure we understand what we giving.

If the controller said max forward, that's what I'll do (with a little margin).

ATC's lack of accurately controlling the situation is not my problem

blee256 · May 23rd, 2007, 23:43

Quote:

Originally Posted by Center_Mid

I had a Caravan, a Lear, and another 172 behind me on the ILS. I heard ATC slow the Caravan down for me and I would guess the Lear had to slow, too. I felt a little bad about clogging the pipeline, especially since it was just a practice ILS in VFR conditions.

Dont worry about the lear and caravan. Let ATC keep the spacing between you the guys. Do the best you can on the speed. If you were really gonna screw up the caravan and lear, atc would have pulled you off the practice approach. So dont sweat it.

And when ATC asks for speed, its indicated and turns to heading are via your mag compass

May 21st, 2007, 11:59	#1
Center_Mid Junior Member Join Date: Jun 2003 Location: Seattle, WA Posts: 213	Which speed keeps ATC happy? Over the weekend, I was flying my club's 172 on the 13R ILS into Boeing Field in Seattle. I'm about four miles from the outer marker and the controller asks me what max speed I could maintain for spacing. I look at my airspeed and power configuration and quickly estimate that I could maintain 120 KIAS. So, I respond with 120. However, as the approach continues, I notice my groundspeed on the GPS is showing around 110-113 knots. No matter what I did power-wise, I would get 120-125 indicated but never more than 113 over the ground. I had a Caravan, a Lear, and another 172 behind me on the ILS. I heard ATC slow the Caravan down for me and I would guess the Lear had to slow, too. I felt a little bad about clogging the pipeline, especially since it was just a practice ILS in VFR conditions. My question is: next time, should I estimate what groundspeed I could maintain or stick with indicated? __________________ "To alcohol - the cause of and solution to all of life's problems." (H. Simpson)

May 21st, 2007, 12:05	#2
TFaudree_ERAU Old Skool Join Date: May 2006 Location: Virginia is for Lovers, yacht chasing on the weekends Posts: 1,774	Re: Which speed keeps ATC happy? The controller works with ground speed. But...remember that all those airplanes behind you on approach are experiencing the same headwind you are. If you are told to maintain 120 KIAS and the wind is holding you at 113 ground speed, then the Lear behind you is doing 160 KIAS and 153 across the ground. Seven knots is seven knots. Stick to indicated. __________________ Charter Member - JC Pilot Motion Picture Society (JC PiMPS)

May 21st, 2007, 12:08	#3
BajtheJino Senior Member Join Date: Feb 2007 Location: Country Inn and Suites Posts: 970	Re: Which speed keeps ATC happy? Indicated.

May 21st, 2007, 12:27	#4
Cessnaflyer Senior Member Join Date: Dec 2006 Location: Sammamish, WA Posts: 1,411	Re: Which speed keeps ATC happy? What club are you in, in Seattle? __________________ Chris, CFI, CFII Now I could let these dream killers kill my self-esteem or use it as the steam to power my dreams That's how you treat things, stay hungry.

May 21st, 2007, 13:50	#5
GaTechKid Old Skool Join Date: Aug 2003 Location: Frigid NWA Hub Posts: 1,882	Re: Which speed keeps ATC happy? Indicated __________________ "I'd rather screw my way around the country then blow my way around..." - Saab 340 Driver

May 21st, 2007, 13:56	#6
Center_Mid Junior Member Join Date: Jun 2003 Location: Seattle, WA Posts: 213	Re: Which speed keeps ATC happy? I'm at Galvin. __________________ "To alcohol - the cause of and solution to all of life's problems." (H. Simpson)

May 21st, 2007, 14:24	#7
SteveC Moderator Join Date: May 2003 Location: GRR Posts: 8,373	Re: Which speed keeps ATC happy? ATC will always talk to pilots with regard to indicated speed, not groud speed. Same with headings versus ground track. Fly the headings and indicated speeds that they give you and let them worry about correction for the winds. They're (usually) pretty good at it. __________________ . Life is painful. Suffering is optional.

May 21st, 2007, 14:41	#8
DE727UPS Old Skool Join Date: Nov 2000 Location: Spokane, WA Posts: 6,482	Re: Which speed keeps ATC happy? I used to go to Bremerton a lot for the ILS rather than mix it up at BFI. You really wanna get some attention. Try holding at NOLLA at 2000 feet...just to exercise your right to be there. You're outside the B and outside BFI's D, just barely... __________________ Click here to see how I became a UPS pilot http://www.jetcareers.com/content/view/65/132/

May 21st, 2007, 17:57	#12
surreal1221 Old Skool Join Date: Jul 2006 Location: Alpha Tango Lima Posts: 8,656	Re: Which speed keeps ATC happy? Whatever speed keeps you from generating a CA on the scope. . . __________________ AGI.MEI.CFI.CFII.FO.CRJ2 \| Josh \|The TRoP \| Ramble On \|ALPA \| Your DD-214 is where?

May 22nd, 2007, 13:22	#17
DE727UPS Old Skool Join Date: Nov 2000 Location: Spokane, WA Posts: 6,482	Re: Which speed keeps ATC happy? I'll have the steak sandwich and.....the steak sandwich. __________________ Click here to see how I became a UPS pilot http://www.jetcareers.com/content/view/65/132/

May 22nd, 2007, 22:32	#19
PurduePilot Senior Member Join Date: Oct 2000 Location: Sherborn, Massachusetts USA Posts: 1,309	Re: Which speed keeps ATC happy? Which speed makes ATC happy? ... the one that keeps you in the air! __________________ Neil Harrison

May 22nd, 2007, 23:25	#20
TonyWilliams Junior Member Join Date: Feb 2007 Location: Oxnard, California Posts: 32	Re: Which speed keeps ATC happy? Indicated or Mach speed

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