Tricks of the trade; Let's fly the NDB 28 KUES

[dmrogers]

Hey folks,
A question for you on instrument procedures:

Let’s assume you are shooting an NDB app. If you’d like to get specific we can speak about the NDB runway 28 at KUES (http://204.108.4.16/d-tpp/0510/05078NG28.PDF has the chart)

You are cruising in a minimally equipped IFR aircraft, no DME, with an approach speed of 120kts. (upgrade your airplane, cheapskate)

You have just exited a hold at BAE, direct to Waukesha NDB, Cleared for the full procedure approach. (Not sure which is harder here; flying the approach or pronouncing the approach.) You notice a substantial amount of westerly correction must be applied to track to Waukesha.

Crossing Waukesha you turn to your outbound heading and start the clock. You estimate a minute and a half for your outbound leg, a minute in the procedure turn outbound, and then turn inbound to track the 115 bearing to the NDB. The inbound is taking noticeably longer than usual.


Milwaukee approach was really bored and had been watching your every move on the radar screen, casually noting that you busted the 10 mile ring from Waukesha. You continue the app, bust out at 1500msl, put her down, then taxi to the FBO.

Well, no “real” harm done, but style points were lost, and technically the rules were broken. No one enjoys loosing style points. Are there any experienced aviators that have a functional technique to avoid this faux pas, while IMC? Is there any other method other than simple guess work?

 

[EatSleepFly]

Is there any other method other than simple guess work?

A clock and a few brain cells.

 

[onthebeach]

A few suggestions

>>You notice a substantial amount of westerly correction must be applied to track to Waukesha.<<

Any IAP requires situational awareness and pre-planning. The requirements go up considerably when you are flying a minimally equipped aircraft. You should know the winds aloft and how they will affect you before starting the approach. In this case, it appears you were surprised by the wind's effect on the aircraft, i.e., "The inbound is taking noticeably longer than usual," is a sign that you were behind the planning curve before you began the approach.

>>Milwaukee approach was really bored and had been watching your every move on the radar screen, casually noting that you busted the 10 mile ring from Waukesha.<<

This is an example of using all your resources. You could have asked the approach controller (or other facility providing radar coverage for the approach) to fix your position for you relative to either IJMOM or UES. They will provide this service on a workload-permitting basis...instant "DME."

>>You continue the app, bust out at 1500msl, put her down, then taxi to the FBO.<<

If you broke out at 1500 "msl", you really have problems, since the lowest MDA is 1900 "msl". Perhaps you meant 1500 "agl."

>>Well, no “real” harm done, but style points were lost, and technically the rules were broken. No one enjoys loosing style points.<<

Cute saying, but in reality you busted the protected airspace on which the approach minimums were predicated and thus could have had obstacle clearance below TERPS standards. Add in a sloppy altimeter, a wrong altimeter setting, a colder than standard day OAT, and some sloppy altitude keeping, and you might have a close shave. It's a serious matter and should be taken seriously. If this actually happened to you, I'd advise filing a NASA form if you're within the deadline for doing so.

>> Are there any experienced aviators that have a functional technique to avoid this faux pas, while IMC? Is there any other method other than simple guess work?<<

Aside from my comments above, you might also consider making the procedure turn inbound turn to the LEFT, instead of the RIGHT, i.e., fly the "barb" outbound (070) for the time you select...which should be considerably less time than normal in this situation...going back to preplanning...then turning left to 250 instead of right. With a westerly wind in this situation that will give about 15 to 20 seconds less time for the wind to "set" you easterly, toward the 10-mile circle. There is nothing incorrect or not allowable about this technique.

Also, you might consider a 90-270 type of course reversal in this situation; with a strong crosswind it would work well.

Last but not least, realize that the MDA is almost 1000 feet above the field. You are going to have to see the runway(s) well out...at least a couple of miles in a single engine plane, 3 miles or so in a twin, and even more in a turboprop or jet...to be able to establish a stablized approach and land straight-in. In the scenario you've given, if you did break out at 1500 "agl" (and also assuming legal and adequate visiblity), you could circle to 28 by flying a complete pattern, i.e., upwind, crosswind, downwind, base, and final to 28.

 

[GravityHater]

Style points, a good term but I have to suggest a harsher one because in such a situation you really have lost the guaranteed terrain separation when you exceed the 10nm ring. Im not saying I've never busted the ring (esp in training) but I do all I can to not do so anymore.
I think it all comes down to the outbound leg. There is no minimum for the outbound leg that I have ever heard. I only use 1.5 mins in a slow plane with a headwind outbound... I get way too bored and want to get things happening! In calm winds with a 120kts speed I'll use 1 minute or sometimes only 30 seconds.
PS You should never be surprised a whole lot by winds in the approach - usually you will know from your briefing what to expect at destination.

 

[dmrogers]

A clock and a few brain cells.

keep in mind you have no ground speed indication

 

[dmrogers]

>>You notice a substantial amount of westerly correction must be applied to track to Waukesha.<<

Any IAP requires situational awareness and pre-planning. The requirements go up considerably when you are flying a minimally equipped aircraft. You should know the winds aloft and how they will affect you before starting the

Good reply!

You noticed all of the pilot observations as well as the "self talk" during the APP that could have been followed to make revisions to the pilot’s “standard” app procedure.

I must confess that the MDA was accidental, due to this approach first being written on the NDB app at KMKE, but being switched once I realized that plate is no longer available for download. Live and learn.



As a foot note, I think I must mention that this situation is purely hypothetical, and I did not intend to imply that I am, nor do I know, a specific pilot who has broken these FAR’s or procedures. I intend to post several hypothetical situations in the interest of conversation, and education.

An important issue was raised as well. http://asrs.arc.nasa.gov/forms.htm is the pilot’s key to likely immunity should the FARs be unintentionally violated, keep in mind that your get out of jail card is limited.

Is this helpful/ enjoyable to anyone?

 

[A Squared]

>>>>>> keep in mind you have no ground speed indication

Yeah, you *do* have a groundspeed indication. the time (using the clock) it takes you to travel between identifiable points. WHy do you think you were doing all that timing of checkpoints on yout Private Pilot cross countries? It wasn't just some sort of pointless hazing.


To bust the 10 mile zone with the timed legs you mentioned will take a groundspeed of approximately 240 knots. 120 knots of wind at 1900 ft agl is a bit unusual. If you haven't noticed a 120 knot tailwind, perhaps you should be paying a little closer attention to what is going on.

Cute saying, but in reality you busted the protected airspace on which the approach minimums were predicated and thus could have had obstacle clearance below TERPS standards.

well, maybe you busted the protected airspace. Depends how far outside the 10 nm you went. If you are within 1000 feet of the correct PT altitude you have 16 NM before you hit something. if you are *at* the correct PT altitude you have 18 miles befroe you hit something.

I'm not suggesting you should use these distances, nor that you should intentionally not stay within 10 nm, just that there's not going to be a brick wall at 10.0 nm from the fix.

 

[dmrogers]

Yeah, you *do* have a groundspeed indication. the time (using the clock) it takes you to travel between identifiable points. WHy do you think you were doing all that timing of checkpoints on yout Private Pilot cross countries? It wasn't just some sort of pointless hazing.


Out bound from the NDB, what is this point that one can measuring their time to, in order to calculate ground speed? This scenario specifically notes that IMC conditions prevail.

Having two identifiable points would certainly make this easy. Lets rule out cross radials from the nearby vor...and attempt to define this point in space that we have measured to. Using *only* the required equipment for this app makes it difficult to judge such things as speed/distance.


ps..Also keep in mind that you riding the turbulence generated by a 120kt low level wind ; )...I suppose I should have upped the app speed a bit for this scenario. Noted. I am learning all sorts of lessons regarding clarity from this one post.
.

 

[MauleSkinner]

Given that I suspect strong westerly winds, I would cross the NDB, turn to a 085 heading, fly for 1:30, and make my right turn back onto the final approach course. Upon intercepting the final approach course, I would target a 1000 fpm descent to minimums. With 20 knots of westerly wind, this would put you about 2 miles from the NDB, probably 1 1/2 miles from the end of the runway...right at the distance for the visibility minimum. Kind of steep for an approach with 1000-ft MDH, but apparently the TERPS say its doable.

On the other hand, it would take something in excess of 120 knots of west wind to blow you out of the 10 mile ring.

This worked pretty well at the airport where I started flying charter, but MDH was only about 500 feet

Fly safe!

David

 

[EatSleepFly]

Out bound from the NDB, what is this point that one can measuring their time to, in order to calculate ground speed? This scenario specifically notes that IMC conditions prevail.

Well, you say you were holding at the VOR, so how long did it take you to fly that 4.8nm between the VOR you were holding at, and the NDB?

Once you arrive at the NDB, you only turn 36 degrees left to go outbound. 36 degrees of heading change wouldn't change your groundspeed enough to be a factor.

 

[A Squared]

Out bound from the NDB, what is this point that one can measuring their time to, in order to calculate ground speed?

If you're outbound form the NDB, it's too late.

Having two identifiable points would certainly make this easy.

Howzabout the Badger VOR and the Waukesha NDB????????? You did say you came from the BAE vor didn't you?

It's 4.8 NM. in calm wind, it should take you 144 seconds. with a 120 knot wind from 295, it will take you 88 seconds. That's almost a minute difference. That should be within the timing capabilities of anyone who should be flying an airplane. no? also you'll have about a 35 degree wind correction on that transition. That should have been another clue that something extrordinary is happening.

Additionally, you said you were *holding* at BAE. Did ya happen to notice that the outbound and inbound legs were a little different timewise? THis isn't rocket sience, but you do have to be paying attention.


I think that the point you should be taking is that you shouldn't be arriving at the NDB without the foggiest clue what winds you're dealing with. The timing and estimating winds should have taken place *before* you were overhead the NDB.

 

[A Squared]

Kind of steep for an approach with 1000-ft MDH, but apparently the TERPS say its doable.

Not a problem, he's got a 120 knot headwind inbound. in a 120 knot airplane, his descent gradient is infinite.

 

[dmrogers]

Well, the winds are 270/170

with the perfect storm wind conditions I have accidentally created....the ground speeds/ crab angles would be this:

Wait never mind….on the route between BAE and the NDB at 120 kts, a 90 degree Wind correction angle wouldn’t make up for my drift…so let’s up the speed to 150 KIAS until the NDB.

From BAE to the NDB, we will hold a 233 heading to maintain course, a mere 82 degree Correction angle…making a ground speed of 102 kts.

Now we cross the NDB, turn outbound and slow her down to 120kias. To track outbound we will hold a 151 degree heading and make a groundspeed of 250kts.

Inbound, we will now fly a 258 heading and make a ground speed of 58 kts.

This is all after we managed to hold at the VOR without noticing the backward progression over the earth’s surface. “Approach N11238, do you still show us on your radar screen, or have to died and gone to Non-published hold hell?”

Prior to that you may have heard “N1234 Hold east of Badger VOR on the 270 radial, Expect Further clearance when you start moving.”

I think someone better get a urine sample to the lab before I post anymore hypothetical situations.

 

[MauleSkinner]

I think someone better get a urine sample to the lab before I post anymore hypothetical situations.

I would say that the major lesson here is that at typical lightplane speeds, staying within the protected area on a "normal" IAP is not that difficult.

If you're flying something with Cat D approach speeds nearing 160 knots, you have less margin, but it would still take nearly 40 knots of wind to push you outside of the 10 mile limit if you were totally ignorant of the wind.

That being said, I used to fly with a guy who not only couldn't stay within the 10 miles, he also only made it down to MDA about half the time before passing the MAP. It took several D-Cell Maglite-sized dents in the back of his head before he slowed down to appropriate speeds and increased his rate of descent past 500 fpm

Fly safe!

David