Lead Radial

[luvflyin]

You’re flying this one from TUS on the Feeder. How would you do it?

 

[MauleSkinner]

RNAV to DRIBB, HILPT, start my turn to the LOC crossing the Lead Radial.

 

[luvflyin]

RNAV to DRIBB, HILPT, start my turn to the LOC crossing the Lead Radial.

Ok. How about you’re using a GPS Navigator that doesn’t fly a real Parallel Entry but joins the inbound course outbound and you’re in a pretty fast airplane. I’m wondering if you’d already be past NIKEE before intercepting the Localizer. Do you have a Simulator you could try this on?

 

[MauleSkinner]

Ok. How about you’re using a GPS Navigator that doesn’t fly a real Parallel Entry but joins the inbound course outbound and you’re in a pretty fast airplane. I’m wondering if you’d already be past NIKEE before intercepting the Localizer. Do you have a Simulator you could try this on?

First off, how is that not a “real” parallel entry?
Second, how fast is “pretty fast”?
With almost 5 miles between DRIBB and NIKEE, that shouldn’t be a problem.

 

[asicer]

Ok. How about you’re using a GPS Navigator that doesn’t fly a real Parallel Entry but joins the inbound course outbound and you’re in a pretty fast airplane. I’m wondering if you’d already be past NIKEE before intercepting the Localizer. Do you have a Simulator you could try this on?

The GPS I fly will ask if you want to fly the HILPT and then if you say "yes" it will choose its own entry (parallel, teardrop, etc).

 

[Jim K]

Ok. How about you’re using a GPS Navigator that doesn’t fly a real Parallel Entry but joins the inbound course outbound and you’re in a pretty fast airplane. I’m wondering if you’d already be past NIKEE before intercepting the Localizer. Do you have a Simulator you could try this on?

I'm thinking that's why they published the lead radial. Once you get to TUS 260, you need to start your turn to intercept the localizer whether you've gotten back to the inbound course of the hold or not.

 

[sourdough44]

Back in the day, it was ‘1% of groundspeed’. That would still work, one can figure distance with DME from the station, for the lead radial. If one plane is 100 knots, the next 200, the LR will be different.

The other method is to eyeball it, message AOB to join. I like to take into account overshooting or undershooting winds.

Doing ‘whatever it takes’, within a safe flight profile is another consideration.

 

[Clip4]

With just VOR/LOC from TUS to Dribb, tear drop descending 5000 in the HILPT, use R258 or R257/if you want an LR. Otherwise just be on the needle for the 60° LOC intercept.

With RNAV, turn when it says to.

 

[luvflyin]

I'm thinking that's why they published the lead radial. Once you get to TUS 260, you need to start your turn to intercept the localizer whether you've gotten back to the inbound course of the hold or not.

That’s not the reason. If there was no HILPT the LR would still be there for the JIPSY DRIBB segment.

 

[Clip4]

I'm thinking that's why they published the lead radial. Once you get to TUS 260, you need to start your turn to intercept the localizer whether you've gotten back to the inbound course of the hold or not.

If you are flying a typical SEL airplane, the turn at R260 is to soon. Dribb is 23 NM from the station. The distance from the lead radial to the LOC on the approach is 1.53 NM. A turn at R257.5 is ~1 NM from the LOC.

 

[texasclouds]

Edit: you are right, TUS to DRIBB is indeed a feeder route.

I guess if your flight plan included TUS from the east, you could do the hold to turn around. I would ask for vectors to final.

 

[midlifeflyer]

With a GPSS coupled autopilot I'll do the parallel entry it will prompt at DRIBB. I'm just along for the ride unless it does something completely unexpected.

Without a GPSS coupled autopilot, teardrop entry for the HILO at DRIBB.

Completely old school, depends a bit on whether I have NAV1 and NAV 2 in addition to the required ADF, but basically, TUS R256 to DRIBB (identified by crossing the LOC or the 305 bearing from ROBLES), teardrop entry to the HILO, then intercept the LOC. TERPS is above my pay grade but I think the lead radial is mostly about having only one NAV; it's a prompt to switch from TUS to the localizer.)

 

[midlifeflyer]

The hold shown on the chart is for the missed approach. The transition from JISPY has NoPT.

JIPSY?

You’re flying this one from TUS on the Feeder. How would you do it?

 

[Palmpilot]

The hold shown on the chart is for the missed approach. The transition from JISPY has NoPT.

It's a dual-purpose hold. Note that "NoPT" is not depicted on the feeder from TUS.

 

[Plano Pilot]

It's a dual-purpose hold. Note that "NoPT" is not depicted on the feeder from TUS.

Sorry, my bad. Parallel.

 

[luvflyin]

First off, how is that not a “real” parallel entry?
Second, how fast is “pretty fast”?
With almost 5 miles between DRIBB and NIKEE, that shouldn’t be a problem.

You parallel the holding course. Not join it like GPS Navigators like to do. Learjet.

(a) Parallel Procedure. When approaching
the holding fix from anywhere in sector (a), the
parallel entry procedure would be to turn to a heading
to parallel the holding course outbound on the
nonholding side for one minute, turn in the direction
of the holding pattern through more than 180 degrees,
and return to the holding fix or intercept the holding
course inbound.

 

[luvflyin]

If you are flying a typical SEL airplane, the turn at R260 is to soon. Dribb is 23 NM from the station. The distance from the lead radial to the LOC on the approach is 1.53 NM. A turn at R257.5 is ~1 NM from the LOC.

Yeah, ya gotta apply the logic check. The Approach will be built to accommodate fast planes the will fly it and the LR designated for that to prevent overshoots. Less than standard rate turn will accommodate slow planes to mitigate undershoot as well as calculating your own LR.

EDIT: Or with a slow mover, say 90 knots, you could probably just forget the the Lead Radial thing. Wait for the LOC Needle to move and then start your turn. I don't know Trig and the math required to calculate radius of turn. But I'm sure someone can do it.

 

[luvflyin]

With a GPSS coupled autopilot I'll do the parallel entry it will prompt at DRIBB. I'm just along for the ride unless it does something completely unexpected.

Without a GPSS coupled autopilot, teardrop entry for the HILO at DRIBB.

Completely old school, depends a bit on whether I have NAV1 and NAV 2 in addition to the required ADF, but basically, TUS R256 to DRIBB (identified by crossing the LOC or the 305 bearing from ROBLES), teardrop entry to the HILO, then intercept the LOC. TERPS is above my pay grade but I think the lead radial is mostly about having only one NAV; it's a prompt to switch from TUS to the localizer.)

The LR is there to prevent overshoots. Waiting for the Loc needle to start moving before starting the turn will create overshoots on steeper angles of intercept.

 

[luvflyin]

JIPSY?

You sometimes plug situations into Simulators and give us the results. If you get the time and are willing, I’d like to see what happens with a fast mover. I dunno, say a 180 knots. Would that be unrealistic? Runways long enough that Learjetty type planes could use the airport. If you can, just let the Navigator do it’s join the holding course out bound thing. And then use heading mode to cross the fix and parallel the course out bound

 

[midlifeflyer]

The LR is there to prevent overshoots. Waiting for the Loc needle to start moving before starting the turn will create overshoots on steeper angles of intercept.

I'm not completely sure about that. Grab a VOR approach with a DME arc. Do you see a lead radial? I think you only see them when the arc and the FAC use different navaids.

 

[luvflyin]

I'm not completely sure about that. Grab a VOR approach with a DME arc. Do you see a lead radial? I think you only see them when the arc and the FAC use different navaids.
View attachment 115985

I don't think that it's different Navaids in and of itself. It's that the Final Approach Course is a Localizer. It's the narrow range of signal. Time to rattle @RussR 's cage. When ya have time can you give us the skinny on this?

 

[MauleSkinner]

You parallel the holding course. Not join it like GPS Navigators like to do. Learjet.

I’ve never flown a GPS navigator that does that.

 

[midlifeflyer]

I don't think that it's different Navaids in and of itself. It's that the Final Approach Course is a Localizer. It's the narrow range of signal. Time to rattle @RussR 's cage. When ya have time can you give us the skinny on this?

That would make sense too.

 

[TCABM]

From FAA Order 8260.19H, Ch8, Section 8-2-5

h. Lead radials. In addition to the angle of interception requirements of Order 8260.3, paragraph 2-4-2.a(1), a 2 NM lead radial (1 NM for Copter procedures) must be published with arc initial approaches when the DME is not collocated with the facility providing the procedural course guidance. The lead radial provides information for aircraft with single receiving equipment to change the receiver to the localizer or other facility providing the course guidance and to ensure the aircraft is within the clearance coverage area of localizer (LOC) facilities before changing frequency or accepting on-course indication.

 

[luvflyin]

I’ve never flown a GPS navigator that does that.

I’ve never seen one that does. They don’t know how to do a ‘parallel’ entry.

 

[luvflyin]

From FAA Order 8260.19H, Ch8, Section 8-2-5

Ah. Wonder how many Approaches out there have DME Arcs from a facility not collocated with the facility providing the procedural course guidance and that is not a Localizer.

 

[NealRomeoGolf]

Ah. Wonder how many Approaches out there have DME Arcs from a facility not collocated with the facility providing the procedural course guidance and that is not a Localizer.

Like the Loc/Dme BC at UIN to runway 22? Localizer on field. Arc is made by VOR not on the field.

 

[asicer]

RNAV to DRIBB, HILPT, start my turn to the LOC crossing the Lead Radial.

Since you're RNAV, won't your GPS navigator tell you when to turn inbound?

 

[MauleSkinner]

I guess the bottom line, as always, is don’t let your GPS navigator take you someplace you don’t want to go.

 

[Clip4]

Yeah, ya gotta apply the logic check. The Approach will be built to accommodate fast planes the will fly it and the LR designated for that to prevent overshoots. Less than standard rate turn will accommodate slow planes to mitigate undershoot as well as calculating your own LR.

EDIT: Or with a slow mover, say 90 knots, you could probably just forget the the Lead Radial thing. Wait for the LOC Needle to move and then start your turn. I don't know Trig and the math required to calculate radius of turn. But I'm sure someone can do it.

Distance from the station / 60 = distance between each degree (radial).

 

[luvflyin]

Like the Loc/Dme BC at UIN to runway 22? Localizer on field. Arc is made by VOR not on the field.

Yeah. But it’s still a Localizer. Lead Radial needed based just on that. What we’d be looking for is something like the Final Approach Course is a VOR. Not a VORTAC or a VOR/DME, just a VOR. But they needed an IAF and Initial Approach Segment that connected to the Enroute Structure and a DME Arc is all that was available. So they used a nearby VORTAC or VOR/DME for the Arc.

 

[midlifeflyer]

Ah. Wonder how many Approaches out there have DME Arcs from a facility not collocated with the facility providing the procedural course guidance and that is not a Localizer.

Probably none, although I guess a DME arc off a VORTAC to a different VOR is possible.

 

[midlifeflyer]

Since you're RNAV, won't your GPS navigator tell you when to turn inbound?

Yes, it will anticipate the turn inbound to meet the FAC and, if set for auto switch, will switch nav sources to the LOC once inbound to the FAF.

But there are pilots who treat all that as a backup when switching from pink to green needles.

 

[Hang 4]

Probably none, although I guess a DME arc off a VORTAC to a different VOR is possible.

What about the ILS 25R at DAB? It uses the OMN VORTAC for the arc to the Localizer. I have to admit, not really tracking this discussion (pun intended)

 

[NealRomeoGolf]

Yeah. But it’s still a Localizer. Lead Radial needed based just on that. What we’d be looking for is something like the Final Approach Course is a VOR. Not a VORTAC or a VOR/DME, just a VOR. But they needed an IAF and Initial Approach Segment that connected to the Enroute Structure and a DME Arc is all that was available. So they used a nearby VORTAC or VOR/DME for the Arc.

VOR 12 at KBRL. Arc is off the VOR that also provides guidance into the runway. The VOR is in another state.

Edit: I need to go fly this one. Not even a 30 minute flight to get over there.

 

[luvflyin]

VOR 12 at KBRL. Arc is off the VOR that also provides guidance into the runway. The VOR is in another state.

Edit: I need to go fly this one. Not even a 30 minute flight to get over there.

There’s lots of Approaches like that.

 

[luvflyin]

What about the ILS 25R at DAB? It uses the OMN VORTAC for the arc to the Localizer. I have to admit, not really tracking this discussion (pun intended)

Looks like you need an LP, Lead Post. Start at post #20

 

[midlifeflyer]

Looks like you need an LP, Lead Post. Start at post #20

I thought your post was fairly clear about looking for a lead radial that is not to a localizer final approach course. But based on the responses showing lead radial that is to a localizer course, I guess not.

 

[midlifeflyer]

You sometimes plug situations into Simulators and give us the results. If you get the time and are willing, I’d like to see what happens with a fast mover. I dunno, say a 180 knots. Would that be unrealistic? Runways long enough that Learjetty type planes could use the airport. If you can, just let the Navigator do it’s join the holding course out bound thing. And then use heading mode to cross the fix and parallel the course out bound

I ran it 200 KTS. I'm not sure what you mean by the juxtaposition of the two things I bolded in your post.

Parallel entry for the HILO as expected. The interesting part is, at that speed, the airplane never returned to the inbound course or to DRIBB. Instead, turn anticipation turned to intercept the FAC directly from the holding side of the HILO (the magenta line).

 

[luvflyin]

I ran it 200 KTS. I'm not sure what you mean by the juxtaposition of the two things I bolded in your post.

Parallel entry for the HILO as expected. The interesting part is, at that speed, the airplane never returned to the inbound course or to DRIGGS. Instead, turn anticipation turned to intercept the FAC directly from the holding side of the HILO (the magenta line).

View attachment 116005

That’s what I was wondering about. Would it start the turn at the LR, before being on the inbound course and what the effect would be. How close to NIKEE would it put you on the Localizer. Looks like about 2.5 or 3 miles out. You shouldn’t leave 5000 until on the Localizer. Were you able to intercept the Glideslope from below? Or did you have to get it from above?
What I meant was let the Navigator do its thing which probably would have been turn anticipation approaching DRIBB from TUS and rolling out on the holding course outbound. Not a ‘true’ parallel entry, but it seems to be how all Navigators do it. I wanted you to also do it crossing DRIBB and then turn to a paralleling heading outbound. Go for a minute and the turn back inbound. That would have you crossing the LR a little further West and subsequently the Localizer a little farther out from NIKEE.