Attempted a DME arc today

Challenged

Challenged

Pattern Altitude
Joined
Apr 4, 2011
Messages
1,901
Location
Louisiana
Display Name
Display name:
Challenged
I'm currently working on my Instrument ticket, so I went up with my instructor and I flew a DME Arc approach for the first time today. I have to say it was pretty interesting and I thought it was a cool experience. I did a pretty good job with it, but I think I could have been a little cleaner if I had a heading bug on my DG, as I found myself a little lost after a couple of turns since the weather was bouncy.

While we were on the DME arc approach, the controller asked if we would mind flying a surveillance approach next, but unfortunately I had to get back on the ground for prior commitments, so we couldn't help her out with that. I had never even heard the term surveillance approach before going up today, so I was sorry that we couldn't do that one as well. It seems like it would be a good procedure for both pilots and controllers to practice every so often.
 
Challenged said:
I had never even heard the term surveillance approach before going up today,
Click to expand...
Most instructors don't teach the use of a surveillance approach, simply because it isn't on a checkride, but now that you know of their existence, try to do at least one; they are good for basic instrument heading/altitude control practice while talking to ATC, and in real life, a no-gyro surveillance approach can be a life-saver.
 
Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10.
Twist 10, turn 10. Twist 10, turn 10.
 
BellyUpFish said:
Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10. Twist 10, turn 10.
Twist 10, turn 10. Twist 10, turn 10.
Click to expand...

I remember my first arc....I think we spent 30 miles turing and twisting.

Now I personally fly it by using the DME as my primary referance (Getting closer, widen out. getting farther, tighten it up) and periodically twist the OBS so I know where I am.
 
Challenged said:
While we were on the DME arc approach, the controller asked if we would mind flying a surveillance approach next, but unfortunately I had to get back on the ground for prior commitments, so we couldn't help her out with that. I had never even heard the term surveillance approach before going up today,
Click to expand...
For those unfamiliar...
2. A SURVEILLANCE APPROACH (ASR) is one in which a controller provides navigational guidance in azimuth only. The pilot is furnished headings to fly to align the aircraft with the extended centerline of the landing runway. Since the radar information used for a surveillance approach is considerably less precise than that used for a precision approach, the accuracy of the approach will not be as great and higher minimums will apply. Guidance in elevation is not possible but the pilot will be advised when to commence descent to the Minimum Descent Altitude (MDA) or, if appropriate, to an intermediate step-down fix Minimum Crossing Altitude and subsequently to the prescribed MDA. In addition, the pilot will be advised of the location of the Missed Approach Point (MAP) prescribed for the procedure and the aircraft's position each mile on final from the runway, airport or heliport or MAP, as appropriate. If requested by the pilot, recommended altitudes will be issued at each mile, based on the descent gradient established for the procedure, down to the last mile that is at or above the MDA. Normally, navigational guidance will be provided until the aircraft reaches the MAP. Controllers will terminate guidance and instruct the pilot to execute a missed approach unless at the MAP the pilot has the runway, airport or heliport in sight or, for a helicopter point-in-space approach, the prescribed visual reference with the surface is established. Also, if, at any time during the approach the controller considers that safe guidance for the remainder of the approach cannot be provided, the controller will terminate guidance and instruct the pilot to execute a missed approach. Similarly, guidance termination and missed approach will be effected upon pilot request and, for civil aircraft only, controllers may terminate guidance when the pilot reports the runway, airport/heliport or visual surface route (point-in-space approach) in sight or otherwise indicates that continued guidance is not required. Radar service is automatically terminated at the completion of a radar approach.
Click to expand...
See AIM 5-4-11 for more, and check the "Radar Minimums" section of your approach ("Terminal Procedures") book for a list of the airports in your area where an ASR is available. Controllers are generally very happy to give them because they have currency requirements to meet on them like our "6HIT" instrument recent experience requirements.​
 
Controllers are generally very happy to give them because they have currency requirements to meet on them like our "6HIT" instrument recent experience requirements.
Click to expand...
I'm in the latter stages (I hope) of Instrument Training and flew a surveillance approach a few weeks ago at ABI. Actually, it was a "no gyro" surveillance approach. As you say, the controller was more than happy to do it.

It was very interesting and gave me even more confidence in the ATC system than I already had.
 
I'm not a big fan of the twist 10, turn 10 stuff. Seems overly complicated for what is a very simple thing. Pay attention to the distance and the groundspeed and you can just bring yourself around without a bunch of actions. You want a groundspeed of 0.

With each new day, there are less and less aircraft with DME. If you're using a 430 for the arc you need to be flying the CDI based on the course on the screen..not the distance to fix. I've seen some owners with 430s that don't realize this. Soon the art of a DME arc using an actual DME box will be forgotten.
 
jesse said:
I'm not a big fan of the twist 10, turn 10 stuff. Seems overly complicated for what is a very simple thing. Pay attention to the distance and the groundspeed and you can just bring yourself around without a bunch of actions. You want a groundspeed of 0.
Click to expand...
That works fine with the right DME, but not all of them, especially the older ones where distance isn't read out to two decimal places, or maybe even not digitally at all. Also, GPS's don't have a GS relative to station readout, and if you have a GPS but no "real" DME, you are still eligible to be tested on basic DME arc techniques, not just arcs on published procedures with a nice magenta line to follow. While "turn 10, twist 10" isn't the final answer, it's a great help at the beginning for learning how to track DME arcs. Once you get the hang of it, you'll develop your own, more advanced techniques, but my experience suggests it's the best way to begin.
 
Last edited:
Jeanie said:
How could you have a ground speed of zero?
Click to expand...

They're talking about the speed shown on your DME box. It shows how fast you're closing in on, or moving away from, a DME station -- not your actual speed over the ground. So, for example, if your distance from the station remains constant (as it should in a DME arc), the speed shown on your DME box (if so equipped) will be zero. It's just running a simple distance-from-station divided by time equation.
 
When I upgraded the avionics I got rid of the ADF, replaced the GNS400 with a 430W and had the option to pull the DME out...decided to keep it and I am glad I did. I have redundancy for DME and if either the DME itself or the GPS goes TU, I have the other equipment to stay legal for those approaches requiring DME. The arcs are fun, although not too many around here, but great practice in flying precisely, altho I'm still not consistently at 0 GS from the station (working on that).
 
DutchessFlier said:
When I upgraded the avionics I got rid of the ADF, replaced the GNS400 with a 430W and had the option to pull the DME out...decided to keep it and I am glad I did. I have redundancy for DME and if either the DME itself or the GPS goes TU, I have the other equipment to stay legal for those approaches requiring DME. The arcs are fun, although not too many around here, but great practice in flying precisely, altho I'm still not consistently at 0 GS from the station (working on that).
Click to expand...

But now you can't listen to AM radio to figure out if there's a stadium TFR to bust :lol:
 
I tried to fly a DME arc today off the garmin 250xl.... Worked fine. Prolly not legal if had been "real" but it was fun. I managed to keep right between 9.9 and 10.2 miles which I thought was OK for a first time in a 152 in weird wind and thermals. Pretty nifty.
 
Jeanie said:
I tried to fly a DME arc today off the garmin 250xl.... Worked fine. Prolly not legal if had been "real" but it was fun. I managed to keep right between 9.9 and 10.2 miles which I thought was OK for a first time in a 152 in weird wind and thermals. Pretty nifty.
Click to expand...
If that GPS is IFR certified, it's completely legal as a sub for a real DME for pretty much all purposes, including this one. See AIM section 1-2-3 and Table 1-1-6.
 
Nope it's not an IFR gps... It's only a 250XL but it works well enough for what I've needed.
I guess in an emergency it could be used for "situational awareness" but I'd have to be behind the situation to get into that kind of an emergency.

And we did the turn 10 twist 10 routine
 
Jeanie said:
Nope it's not an IFR gps... It's only a 250XL but it works well enough for what I've needed.
I guess in an emergency it could be used for "situational awareness" but I'd have to be behind the situation to get into that kind of an emergency.

And we did the turn 10 twist 10 routine
Click to expand...
Good training/practice anyway, and +/- 0.2 nm is outstanding work.
 
In general I prefer to be in a real plane as opposed to a sim, however, my own ability to fly DME arcs is almost entirely due to Microsoft flight simulator. Obviously, it's no an approved device, but I was absolutely horrible at DME arcs until I spent a bunch of time practicing them in FS. Since then, they haven't been so bad in the real plane.

FWIW.

~ Christopher
 
jwriteclub said:
In general I prefer to be in a real plane as opposed to a sim, however, my own ability to fly DME arcs is almost entirely due to Microsoft flight simulator. Obviously, it's no an approved device, but I was absolutely horrible at DME arcs until I spent a bunch of time practicing them in FS. Since then, they haven't been so bad in the real plane.

FWIW.

~ Christopher
Click to expand...

I think the sim is great for instrument practice and emergencies. (Emrgencies because you can sometimes more acurately simulate the situation safer) Just don't start saying 'with you' or think it'll help you learn how to land...

<---<^>--->
 
You must log in or register to reply here.
Back
Top