Navigational
equipment required:By Andrew Herd
Navigational
equipment required:Standard basic avionics fit plus ADF. No DME is required.
The tutorial is written for Steve Small's Cessna 182RG flight model combined with the DreamFleet Cessna 182RG panel, although the Microsoft default Cessna 182RG could be used. Both these aircraft have a lush avionics fit - if you want to try something a bit sparser, Fred Banting's Mark 1 Beaver would be a good choice.
Penticton.zip - extract all these files into your \FS2000\pilots folder. You might also like to try Rob Abernathy's cyyf.zip which transforms Microsoft's rather boring default airport into something much more interesting - and includes some of the obstacles that make this approach what it is.
Penticton.zip - extract all these files into your \FS2000\pilots folder
This is a non-standard NDB approach which potentially involves some steep descents. A crosswind scenario and a missed approach are included.
Please make sure you have Indicated Airspeed (IAS) set. If you have True Airspeed set, the instructions which follow will make no sense at all. Also, ensure that you do not have gyro drift checked under the realism settings, unless you are proficient at making corrections for this. Do not use the GPS on pain of death - and if the panel you are using is equipped with DME do not set it as you will learn more without it. If you do not have appropriate approach plates, click on the image at the top of this page to view a Final Approach plate courtesy of Georges Lorsche.
Situation 1: select flight Penticton182rg
In the first situation you are approaching the YYF NDB in IFR conditions on
a course of 140 degrees at an altitude of 7800 feet, which is the Minimum Safe
Altitude for the sector defined by the courses 090 and 180 to the YYF NDB. In
general the entry to the approach structure (i.e the route shown on the approach
plate) is by VOR or NDB navigation along airways shown on the en-route charts,
or by connecting procedures known as transitions, but for the purposes of this
tutorial I have placed the aircraft manually.
The aircraft is stable with 120 knots on the Airspeed Indicator (AI), and you are far enough away from the NDB to be able to get sorted out. All the radios are set up, with the exception of the NAV1 set, which I have intentionally left unset. If you are usign the DreamFleet Cessna 182RG panel, which I recommend, set the second NDB radio to 312 now and zoom the timer and the HI. The purpose of this exercise is to practice an NDB approach and we are going to assume that the ILS at Penticton is out. Note that the airport elevation is 1129 feet, so we are not going to fly the altimeter down to zero, or you won't with me on board, anyway.
The first thing to notice is that this is not a common or garden NDB approach. The description line reads "NDB NDB-A" which means that there is a problem hidden in this benign-looking approach. If you check the plan view, it isn't that the final approach segment is out of alignment; the problem is that the descent rate for a straight-in approach from the FAF at the UNT NDB is a stunning 628 feet per nautical mile - twice the rate regarded as normal. That is why no straight-in minima appear on the approach plate and only circle-to-land minima are published.
The other reason the approach is non-standard is that two NDBs are involved. The majority of NDB approaches only have one NDB and don't involve any frequency shuffling - you just fly out from the beacon, do the procedure turn and start your descent to the airport. The use of two NDBs is very unusual, but in this case much of the approach is executed below hilltop height, and there is a pressing need to be very sure of where the aircraft is at all times.
Initial Approach Fix
Your
first task is to maintain your course and altitude to YYF by watching the ADF
needle, the HSI and the altimeter. Manifold pressure should be 23 inches and
RPM at 2400, which will give you an IAS of around 115 knots. Trim the aircraft
so that it will fly hands off, and watch the ADF. YYF is your Initial Approach
Fix (IAF) and you will begin the approach here. If you look at the profile view,
you will see that the thick vertical line above the YYF NDB has the figure 7500'
next to it - and 6371' in parentheses, which is the height above the airport.
7500 feet is the minimum altitude from which you can begin the approach, although
you can begin at a higher altitude should you find it necessary. Notice the
"racetrack": this is a holding pattern based on the NDB - this is
where you run to after a missed approach. Because the holding pattern is drawn
with a thin line, it means that it isn't part of the approach procedure. As
you fly to the NDB, you should keep within 100 feet of altitude and five degrees
of course if you can. This is good practice, and you will need to fly to very
tight limits to complete this approach successfully. Watch the ADF needle -
before long the pointer will begin to fall, and when it reaches about 90 degrees
to one side or the other, I want you to do a turn to starboard all the way around
onto a course of 340.
Outbound leg
The
first trap to beware of is that the ADF needle points at the NDB whether you
are approaching it from north, south, east or west. Both we and the tower at
Penticton, however, want us to fly on a course of 340 to the UNT NDB and there
will be words when you get down if you don't manage it. So once you have completed
the turn, enter the UNT NDB frequency of 312 into the ADF (if you are using
the DreamFleet 182 RG, just swap frequencies), alter course to 340 on the HI,
twist the ADF card to the same heading and take a look to see where you are
at. In all likelihood, the ADF needle will be pointing five or more degrees
to the right, which means that the Cessna is positioned to the left of the line
made by a course of 340 drawn between the two NDBs. The NDBs are close together
and there isn't a lot of time to get on track, so here is how you do it. If,
when your DG shows a heading of 340, the ADF shows a deflection of 5 degrees
right when the radio is tuned to 312, turn the aircraft right TEN degrees to
360 on the HI and fly that heading until the ADF needle is deflected ten degrees
left (to 330) - then turn back onto 340 on the HI and you will be on track with
the ADF needle pointing straight up.
Once
you are happy you are on course, reduce manifold pressure to 15 inches, cut
the RPM to 2000 and begin a descent to 6500 feet. Given that the procedure turn
must be completed within 12 miles of the threshold, and that you want to stabilise
the aircraft before beginning the turn, you have perhaps 7 nm to make your descent.
If you crossed the NDB at 7500, you have only a thousand feet to lose. If you
crossed the NDB at 7500, you have only a thousand feet to lose. At 7000 feet,
an IAS of 120 knots translates into a groundspeed of nearly 133 knots, which
means that you will cover the distance in just over three minutes, translating
into a descent rate of 333 feet per minute.
Once you are established outbound from YYF, watch your course and altitude
as you fly the VSI, and make sure that you don't descend below 6500. When the
ADF needle swings, start to level off, increase mainfold pressure and your RPM
to cruise settings again and raise the flaps so that you have a safety margin
of airspeed for making the turns. Allow about twenty seconds to elapse after
you fly over the beacon and then turn left onto 295 - as you do, reset the timer.
DO NOT FORGET THIS! We are now going to do what is called a "procedure
turn." Although the courses and altitude on procedure turns varies, the
basic method doesn't. Fly this one and you have done 'em all. Fly outbound for
one minute, again, making sure you don't descend below 6500 feet. One piece
of advice is: do not go hell for leather outbound. The slower you go, 
the
more room you leave yourself to get round. While you are on the outbound leg,
reset the heading bug on the HI and the ADF card to 160, which is your inbound
course. When the timer reaches a minute, open the throttle a little and make
a turn onto 115, concentrating on not losing any altitude as you go around.
Then hold 115 and fly back - not for one minute, but for as long as it takes
for the ADF needle to fall to 205 degrees on the ADF card. Why 205? Because
45 degrees is the intercept angle for the course back to Penticton and 160 plus
45 is 205. While you are waiting for that to happen, stop and reset the timer,
because you are going to need it one more time.
When the ADF needle nears the target, turn right onto 160, check your alignment with the NDB (bear in mind that you may be close enough to it that the needle will already be swinging) and fly back towards the airfield. Once you are established inbound, you can start a cautious descent to 5900 feet, but you are not permitted to go below that until you cross the UNT NDB (you will know that you have when the ADF needle swings right around and points back). UNT is the Final Approach Fix, or FAF and this is shown by the propellor-like cross where the descent profile intercepts the NDB.
Once you are past the FAF you can descend again, this time to a minimum of 3800 feet - unless you can go visual earlier. Start the timer, but resist the temptation to tune the YYF NDB frequency, because the plate tells us to wait until the mid-point between the NDBs until we do so. Given that the chart helpfully tells us that the distance is 6.6 nm, and that at this altitude and temperature, 80 knots indicated translates to 84 knots across the ground, you would cover the distance in about 4 minutes 45 seconds. At this point, if you are flying the DreamFleet RG, you should start planning for a missed approach by dialling 356 in the second ADF. This is the frequency for the Okanagan NDB (they have great beer there, by the way) and the DreamFleet dual ADF setup allows you to swap it in real quick should you need to.
Inbound leg - decisions
Now
notice that no straight-in minimums are published. This does not preclude you
from doing a straight in landing, using the circling minimum, as long as you
have the runway in sight early enough to do a normal approach. However, my suggestion
is that unless you have lead in your boots you ain't gonna make it. In the 7.6
miles which are left between the FAF at the UNT NDB and touchdown, you are going
to have to lose 4,800 feet, which can only be achieved at a comfortable descent
rate by dropping the gear (we are going to have to do it sooner or later, anyway)
and pulling full flaps. If you do this, then the airspeed will stay around 80
knots, stretching the approach time to a relatively leisuredly 5 and a three quarter
minutes, and allowing a slowest possible descent rate of a potentially slightly
less ear popping 1000 feet per minute, which would allow you to intercept the
glideslope from above about 2.5 nm from the threshold.
Circle-to-land
If
you decide not to attempt a straight in approach, then you should plan to
"circle-to-land" which means that you should fly down to 3800 and
then enter as normal a traffic pattern round the field as conditions permit,
assuming you are visual at the MDA. There are benfits to doing things this way.
A descent from 5900 to 3800 feet can be made at a very comfortable 700 feet
per minute; all you have to remember to do is to open the throttle a little
at MDA and pick up some flap so that you have sufficent reserve of airspeed
to go around. Take a look at the circle-to-land box. There is a grid with the
letters A, B, C and D in it, with maximum speeds next to it and a single MDA
covering all four categories. The letters refer to what are known as "approach
categories" and they are calculated by multiplying the stall speed in landing
configuration by 1.3 - which puts the Cessna in category A. The MDA section
reads 3800' (2671') -3 which means that you may not descend below this height
until the aircraft is in a position to make a normal descent to intercept a
normal final approach. The 2671 figure is your actual height in feet above the
airport, and the figure 3 means that you cannot execute the procedure unless
you have 3 miles vis. Remember that you can only circle-to-land if the aircraft
is configured for landing and furthermore, in a category A aircraft you must
remain within 1.3 miles of the runway (this isn't on the chart, but that is
how it is) while you are doing the circuit, even though the visibility is greater
than that. And finally, notice that you may not circle to the east of the airport
at all - runway 34 has a right hand circuit if you examine the airport chart.
This means that you need to be extremely careful watching for traffic.
You
can begin your descent below 3800 under three conditions:
1. You can see the airport
2. You can see the threshold
3. You can clear obstacles on the approach by the required amount and the aircraft
is in a position to carry out a landing.
Given that the plate shows a tower of 1820 feet near the southern end of the runway, which you would be required to clear by at least 300 feet, this means that you shouldn't descend lower than 2120 feet as you begin your downwind leg if you have to fly over that tower. Assuming that you are stable at 80 knots, this would mean that you would have to lose 1100 feet on the leg before you could make a turn onto base at a maximum of 45 seconds after the threshold passes abeam your left shoulder (another way of judging this is to begin your turn onto base as the threshold begins to slide out of a three-quarter back view). Fortunately the tower doesn't exist in Flight Simulator, so you can begin the downwind leg at a normal circuit height. After that, all you have to do is turn onto final, throttle back and sink right down onto those numbers.
Situation 2: Arriving high at the IAF- select flight Penticton182rg9300
This
situation places you outbound on the 057 radial from the Princeton VOR, heading
toward the YYF NDB. If you arrive at the IAF at much over 9000 feet, you could
have trouble getting down to 6500 for the procedure turn. On some approaches,
this wouldn't be a problem, because 6500 is the minimum height for the
turn, but if you arrive at UNB too much higher than that, you will have trouble
losing enough altitude on the approach leg, which is steep enough if you begin
at the minimums. The trouble is that the more you pitch down on the descent,
the faster a clean aircraft will go, and the quicker you travel, the less time
you have, so the steeper you have to make the descent and so on, until all the
passengers are screaming and the wings come off. If you want to make friends
and influence people, the object of the exercise is to achieve a comfortable
descent rate in the region of 700 feet per minute or less. At 700 feet per second,
which is achievable as long as you can slow the aircraft enough to cover the
distance between the two NDBs in three minutes, you can cross the IAF at at
9600 feet and still get down to 6500 on time. So the solution is to drop 10
degrees of flap. You should hold a fairly stable approach at around 80 knots,
which will allow a comfortable descent rate to UNT.
Situation 3: Coping with a crosswind - select flight Penticton182rg8500
In
this situation I have added a crosswind to make the approach that little bit
tougher. If you are comfortable with the idea of flying a crosswind, then just
get on in there and try it. You are approaching the IAF from the west at a height
of 8500 feet, so maintain your course until the ADF needle swings and then turn
to 340 as usual. Given the wind direction and speed (from the east at about
ten knots), it would pay to begin the turn over the IAF a little early, as an
insurance policy against having to recover ground from a position west of track.
The weather is not quite as good this time; prepare for some gusts and the wind
will do its best to push you off course. This is an opportunity to practice
"bracketing" a course, but you only have about three minutes to get
things right - if you aren't used to flying in a wind, you can compensate by
maintaining a heading of about 345.
The big challenge of this situation is staying on track between the NDBs. The wind will swing southwesterly on approach, but on the whole it will tend to push you west the whole time. If you don't stay on track, the danger is that you will pass to the west of the UMT NDB, with the result that you may have difficulty completing the procedure turn. Once you are on the inbound course make sure you don't descend below the MDA and keep a close eye on your track - it is very easy to get blown off course on the inbound leg and the whole town will have a grandstand view of you as you try to crab back on track.
Situation 4: Missed approach - select flight Penticton182rgmissed
This
is the worst case scenario. The winds are much as before, but the cloud base
is on the deck and the visibility is not good. Make your descent from UNT as
usual, but you will find, unless you get very lucky with FS2000's cloud distribution,
that you are still IFR at 3800. You might just discern the threshold as you
cross the the Missed Approach Point (marked with a bold upper case M where the
descent profile crosses the YYF NDB,) but I wouldn't call the conditions suitable
for a visual descent, and the guys in the tower will have no-one else to distract
them from watching you, so don't try going any lower unless you plan to do a
great deal of explaining.
At this point your clipboard falls on the floor and slides under the seat. You did read the missed approach section, didn't you?
On a Jeppesen chart, the missed approach instructions are just below the descent profile. In this case, you need to climb out to the ON NDB on a track (note the word "track" not "course") of 152 degrees. You should reach the NDB at 6600 feet, then make a left turn to intercept a track of 321 back to the YYF NDB at 7500.
Clean up the aircraft, advance the throttle and pitch, then begin a climb up to the NDB as soon as you can. If you are using the DreamFleet RG panel, you can just swap frequencies, if you are in the default plane, you will have to exercise your mouse some. I am going to leave you to figure out how to fly this part of the scheme, but when you get to YYF, you can practice a teardrop entry into the holding pattern, because that is where tower will undoubtedly stick you while they work out where to get you down.
Enjoy
Andrew Herd
