In this article, YouTuber and flight simulation guru Novawing24 introduces us to the basic elements of IFR (Instrument Flight Rules) within the world of FSX: Steam Edition.
Note that I used the term “art”, because IFR is more than just following the visual clues of the world around us, or simply pushing a few buttons. In this article I am going to introduce you to some of the tools which will aid you in flying on instruments. Technically, we could simply plug our flight plan into a GPS and let the wonders of modern technology guide us, however we will not be doing this today. To start off, I will first run through the four main elements we will be interacting with – DME, VOR, ADF and ILS (can you tell pilots love their TLA’s?)
DME – Distance Measuring Equipment
A DME allows you to know the distance between you and the site of the DME. DME works by you inputting the DME frequency into your NAV radio. This sends a signal to the station which the station then returns. The time taken for the signal to be returned allows the calculation of not only how far away you are from the site, but also your groundspeed and time to or from the site. Each DME site has a unique Morse code identifier that should be checked before you use it for navigation. As well as being used for en-route navigation, DMEs are utilized in conjunction with other navigation aids to form part of an approach by providing azimuthal (vertical) information.
VOR – VHF Omni-directional Radio range
A VOR is a ground based transmitter that sends a signal out in 360⁰. As the signal from these stations is VHF (Very high Frequency) it is line of sight only, something to be very aware of when travelling over varied terrain or at lower altitudes. In the cockpit of most aircraft there is a VOR gauge that will show a “TO” or “FROM” flag to indicate if you are travelling towards or away from the VOR. If the VOR is out of range, or the signal is masked by terrain, a red flag will appear in its place.
Often a VOR is collocated with a DME so the same frequency will give you both sets of information. Navigation using VOR is fairly logical. On the gauge, dial up your desired heading or radial to or from the VOR. The gauge consists of a needle that moves left or right and will be centred when you are on course. The gauge is actually quite logical as you manoeuvre the aircraft towards the needle to get on course. Aircraft often have two VOR receivers and gauges in the cockpit, one linked to your HSI (horizonal situational indicator) and one that is only used for VOR (see below)
ADF – Automatic Direction Finding
ADF and the accompanying ground component – a Non-Directional Beacon (NDB) – is perhaps the oldest instrument navigation aid out there. In recent years the use of ADF/NDB navigation has declined with the rise of VOR and GPS navigational aids so this type of instrument navigation is not as common as it once was. ADF navigation differs from VOR in that the needle should always point to the NDB (unless it is out of range, then it should sit horizontally).
Additionally, ADF is not as accurate as VOR, and requires more attention to be paid to it to be used successfully including paying close attention to the affect wind velocity is having on your aircraft to ensure you stay on track. This is due in part to the ADF needle being “heavy” and that by its very nature there is a +/- 5⁰ variance. If the needle is pointing to the left you will need to turn the aircraft left until the needle is indicating just to the right of track. You will then need to turn the aircraft slightly left again onto a revised heading to allow for the prevailing wind velocity to actually maintain the required course track.
As a side note for those who have OZx’s Australia packs, they include several AM radio stations which can be dialled in on your ADF to aid in navigation. The ADF/NDB combination is fast disappearing from the aviation world, though is still seen extensively in Eastern Europe and Russia as approach aids (usually in the form of 2-4 NDB’s along the approach corridor).
ILS – Instrument Landing System
ILS is essentially a combination of a VOR and DME with an additional element to aid pilots to remain at a safe elevation when approaching the runway for landing. ILS is VHF frequency based but with a much shorter range. The DME component tells the pilot how far away from the threshold we are, the VOR component will let us know whether we need to turn left or right to line up with the runway while the additional elevation component will allow us to remain on the glideslope for our approach. When displayed on a gauge it is essentially the same as a VOR display with a needle left or right (the Localiser) but with a second needle showing us the vertical (the Glideslope).
Like with VOR, you fly towards the needles, ideally maintaining them in a cross position during the whole approach. There is an additional safety feature provided for ILS approaches with a series of markers down the approach corridor (these are the coloured OMI lights you see in the cockpit). At the very minimum, an ILS approach will have an Outer and an Inner marker (and most have a Middle marker as well) that will illuminate in the cockpit. This allows you an extra layer of safety to check the aircraft is at the correct height for the approach.
An ILS approach requires you to dial in the runway heading (this usually differs from the runway number by up to 3⁰) much like you would when dialling in the radial for using a VOR. You should be receiving the localiser signal before you cross the Outer marker. From there, it is a case of adjusting the aircraft’s pitch and power in order to set a suitable rate of descent, then keep the two needles in the centre of the dial by adjusting yaw and roll all the way to the runway.
As you approach the runway the needles become much more sensitive, so more delicate adjustments are required. As a side note, on modern aircraft the HSI Glideslope “needle” may not stretch across the whole gauge and may only be along the outer edges.
Whew, that’s a lot of information isn’t it? Now I know that all seems very complex, but once you practice it, it becomes second nature. While we’re here though, let’s put these new found skills into practice with a quick trip around Hawaii in the Mooney Bravo.
So we are going to start on the island of Lanai (PHNY), fly from the VOR there (LNY) on the 107⁰ radial, to Upolu Point VOR (UPP). From UPP we will fly the 103⁰ radial for approximately 60 NM. This will place us at a point where we should be able to turn onto the ILS for Runway 26 at Hilo International (PHTO).
So once in the cockpit of the Bravo, we will set our initial NAV Radio frequency to LNY (117.7) and dial in the heading to the outbound radial we wish to fly 107⁰.
Once we are airborne and the aircraft is cleaned up, we will follow the direction of the needle until it begins to centre to know we are on course. The great thing about flying VOR to VOR is that one will complement the other. So after flying for about 40 NM we switch over to the UPP VOR (112.3) without changing our heading (because we still haven’t reached it yet). Now if everything has gone according to plan the needle will barely move, but the Flag will change from “FROM” to “TO”.
Watching our DME, we can see that we are now nearly over the top of the VOR, so now is the time to change the radial we will fly for our next leg. This leg is approximately 60 NM on the 103⁰ outbound radial. While you are within about a mile of the VOR the needle will behave strangely so turn the aircraft onto 103⁰ magnetic and once you are passed the VOR and the DME is increasing resume following the needle. As we enjoy the beautiful Hawaiian scenery we consult our charts to show that the ILS for 26 is 110.7 at 260⁰ so dial in the ILS frequency into the alternate NAV1 frequency ready to switch. The DME from UPP now shows us just under 60 NM away so we now switch the frequency to the ILS, adjust our heading on our HIS to 260⁰ and turn towards the runway.
As before we fly towards the needle and then as it centres we turn on course. From here we keep the two needles as close to a cross as we can as we approach the runway. Remember the closer you get to the threshold the more delicate your adjustments.
And there we have it! We have successfully conducted a flight between the islands using only instruments!
There are lots of ways to test yourself and practice. One of the best things to do is fly on instruments in good weather to practice the basics. If you use something like Plan-G you can take a screen shot of your flight path and save it. Then practice the same flight plan and procedures at night then screenshot the Plan-G view afterwards and compare how you did.
So that rounds out my basic introduction to flying on instruments, there are lots of great resources out there to help hone your skills including FS Academy: On Instruments available on Steam as well as the tutorial missions built into FSX:Steam Edition.
Until next time, pilots!