I was looking to upgrade from the single-engined Cessna Caravan to a twin-engine aircraft. I had considered the Beechcraft Baron B58 (which comes with X-Plane), the Cessna C340 and the Beechcraft King Air B200 (both of which have models made by Carenado). But other than the extra engine, they didn't seem to offer much more of interest. Meanwhile I've realized most of the other players flying online on IVAO (https://webeye.ivao.aero/) are flying airliners, so it would be nice to take a step closer to the big boys.

So after spending some time on the forums and reading reviews, I settled for this "twin engine" aircraft:

It's the ATR 72-500, an aircraft that is already quite familiar to many in Malaysia, as it is quite commonly found serving local and regional routes (I haven't personally been on one though). The ATR 72-500 is a twin-turboprop engine aircraft, built by a joint-venture between the french Aerospatiale (now owned by Airbus) and Aeritalia (now Alienia Aermacchi). The name ATR stands for "Aerei da Trasporto Regionale" or "Avions de transport régional" depending on which language you prefer.

The model in X-Plane is produced by McPhat Studios and published by Aerosoft. It uses Ultra-HD textures, making it one of the most detailed 3D aircraft models you can buy for X-Plane. Here are some videos to show it off (set the resolution to 1080p if you can):

While the detailing and modeling are top of their class, the ATR72-500 is considered "lite" in terms of aircraft systems simulated -- i.e. not everything in the real aircraft is present in the model. So some switches visible in the cockpit are just "dummy" switches. They're mostly to do with stuff non-essential to flying. The idea was to be able to get you up in the air without having to spend 20 minutes on the ground configuring the aircraft. Given that I've flown mostly General Aviation aircraft and this is my first airliner, that's probably a good thing for me.

The model was not available on Steam (an online software store), despite being published by Aerosoft. So far most of my X-Plane purchases have been on Steam, which I find useful as it manages the installation and updates for me, and I only have to remember one login. To get the ATR 72-500 model, I had to create an ID on Aerosoft's own website and purchase and download the model from there, and unzip it into my X-Plane Aircraft's folder. It costs EUR25.17.

You can download a number of other Ultra High-Definition liveries for the model from the McPhat Studios web page. I also found quite a few liveries available on the XPlane.Org forums, so I added the Malaysian airlines to my collection:

Inside the ATR 72-500

Ok enough with the external cosmetics, let's actually board the aircraft. There are two doors on the model, a front cargo door and a rear passenger door, which you can open with shift-F1 and shift-F2 respectively. It's interesting to note that passengers board the ATR72 from the rear of the aircraft, which means that unlike the 737, the ATR can't use aerobridges available at larger airports, as the wings get in the way. The rear doors come with built in steps, so you don't need ground services to provide passenger stairs. There are no cargo bays below the passenger compartment, and instead luggage is stored in the front of the aircraft, behind the cockpit.

When you step into the cockpit, you're greeted by a myriad of switches and dials:

Wow, how am I ever going to figure all this out? It's no 747-200 but coming from the small General Aviation planes this still does look daunting.

X-Plane's View System

The first thing was to sort out the views. With a standard 45 deg field of view, you can't see many instruments at a time if you want to view them in detail. In smaller aircraft, I've managed to get by with using the mouse and arrow keys to move my point of view and perspective as and when I needed to. But this is a much larger cockpit, so a different strategy was needed.

I ended up kicking myself for not learning how to use X-Plane's view system sooner. It's so simple. It uses the number keys on the numeric keypad. You first set up your point of view and perspective, and then hold down the control key and a number key of your choice. X-Plane saves the view settings under that number. To return to this view, simply press the number key (without control) on the numeric keypad.

I set up my views like this:

  1. FMC Panel and NAV settings
  2. Radios
  3. Outside Chase View
  4. Pilot's main instrument gauges
  5. Engine monitoring
  6. Levers
  7. View out from Pilot's side
  8. View out from center of cockpit
  9. Overhead Switches

Saitek Throttle Quadrant

In anticipation of going "twin-engine", I purchased an additional Saitek Pro Throttle Quadrant. This gives you an additional three levers, so you can assign them to separate engines and independently control them. In X-Plane, you can actually fly with a single lever controlling both engines, which is actually simpler, but you lose some of the realism that flying a twin offers -- e.g. the S.O.P. for the ATR 72-500 is to begin taxing with only one engine started, and you can also simulate a single engine failure properly with independent controls.

The add-on model (PZ45) is slightly different than the one that comes with the Saitek Yoke set, in that it connects directly via USB (the original connects to a mini-din port on the yoke base). It shows up as a USB HID device, with three analog axes and 6 buttons. I had a bit of an issue with my desk however: due to the position of my yoke/keyboard and monitor, I did not have enough space to mount two quadrant's side by side on my right hand side. I solved it with a bit of DIY -- I dug out the rotary tool and cut out a piece of stiff plexi-glass to use as a base to hold the two quadrants next to each other, so that I only need to have one clamped to my desk. The end result was a bit shoddy and I mis-drilled some holes, but the result is quite sturdy and the holes are not visible.

I assigned the axes and buttons as follows:
The ATR 72 doesn't actually have a fuel mixture lever, rather that lever is called the "condition" lever which ranges from Fuel Shut Off (0%), FTR/Feather (25%), Auto (about 70%) and "OVRD" at (100%). The "PROP" lever actually controls the "PWR MGT" knob on the dashboard, which can be set to "MCT" (Maximum Continuous), "TO" (Take-Off), "CLB" (Climb), and "CRZ" (Cruise). I chose not to map the PROP lever and just use the on-screen knob.

Having the starters on dedicated buttons is very useful as most start procedures require you to engage the starter while monitoring some other reading and responding when it reaches a certain level. With the position of the starters on most aircraft and the limited view onscreen, it's not possible to use the on-screen starter switch while monitoring anything else.

I also installed the X-assign plugin (http://forums.x-plane.org/index.php?app=downloads&showfile=12551). This allows you to save your control settings on a per-aircraft basis. This way I can have different assignments set for the twin-engine ATR-72 vs the single-engine Bonanza A36, for example. The plugin takes care of loading the settings every time a different aircraft is loaded.

I wonder what I'll end up doing when I move up to a four-engine 747 or A380? (Update: The 747 and A380 need just one lever per engine, there is no Condition lever. So I should be fine).

First Flight

The immediate urge is of course to take the plane up for a test-flight. But since I've got my X-Plane set up to start up with a "cold and dark" cockpit, the initial challenge is to figure out how to start the engines.

The model comes with 2 documents, a 75-page "manual" that describes the aircraft's systems and features, and a briefer 28-page "Procedures" manual, which has checklists for the "normal" things such as starting up, taxing, taking off, cruising, descent, approach, landing, and shutdown. The checklists are written in the usual terse style that assumes you know what's what and where in the aircraft. I didn't and so it wasn't of much help.

So what do you do when you have a new toy but don't want to bother studying the manuals? You search YouTube! I found this (https://www.youtube.com/watch?v=Khew5rG-e0E) helpful video that shows you the exact sequence of button and knob presses to start the engines. The video is a great help as you can actually see which button or switch needs to be toggled. So i followed the steps in the video ... and the propellers are spinning! The sound is not as great as a Cessna Caravan, but that could be because you're not sitting a few feet away from the engine and the cabin is also pressurized, thus insulating yourself from most outside sound. Engines running, I released the parking brakes and the aircraft started to taxi out of the hangar ...

... and I immediately felt how much heavier this aircraft is, and how slowly it responds to controls. I was pushing the rudder pedals (which drive both the rudder on the tail and the nosewheel tiller) all the way to the left and the aircraft was hardly turning. This can't be right, how on earth do you navigate around an airport like this? It was not a PC hardware problem as I could see the rudder pedals and tiller move in response to the controls. The plane kept going forwards, and it was only when I was at 40 knot ground speed did it seem respond. It looks like the tail rudder was working, but not the steering to the nosewheel. Something was very obviously wrong.

Ok lets cheat, and re-start the sim with the aircraft positioned on the runway. That way I don't need to taxi. Aligned on runway 33, i started the engines and powered up the plane for take off. The aircraft rolled down the runway, and the first thing I noticed was how smooth and straight it ran. After a reasonable airspeed (I guess, as I hadn't read the manual) I pulled back on the yoke and the aircraft was airborne. By having two engines spaced out on the wings (instead of on the fuselage) there was none of the torque or prop wash induced sliding and banking that needed to be countered.

At 400 feet I raised the landing gear but there was no increase in airspeed. I switched to an external view again and saw the landing gear still down! I tried dragging the onscreen lever and also pressing the "G" key, but it didn't want to budge. More bugs! Grrr ...

I decided to return to the airport (For some reason, despite just being a Sim, once you're in the air you always feel you have to fly properly back to the airport before ending your session. Deliberately crashing or simply exiting the sim feels "wrong" somehow!). I did a 180 degree turn north of Subang airport, and aligned the aircraft to the runway for final approach. Despite flying much faster than I was used to, everything about flying the aircraft felt smooth and calculated, probably due to being much larger and having a balanced pair of engines. I lowered the flaps to reduce speed ... and nothing happens. Switching to external view confirmed that the flaps were still up. Just to be sure this wasn't X-Plane trying to simulate a failure, I went into the "Aircraft -> Failures" menu and pressed the "reset functions to operational" and tried it again, but still no luck. This appeared to be something wrong with the software itself.

I pulled back the power lever to nearly zero, and brought the plane down onto the runway. Again, everything felt smooth and the plane flew very well, but how am I supposed to fly with no nose wheel control, no gear and no flaps? It's a joke.

At that point, I get a phone call (in real life silly, don't you know you're not allowed to use your phone in the aircraft? *grin*) and left to meet my colleague at the nearby mamak stall (cafe). I got there first, so started reading through the manual, all the while thinking what a waste of money this plane was, when I came across this paragraph:

6.12 Hydraulic System

The aircraft has two hydraulic systems, designated blue and green. The common hydraulic tank is located in the hydraulic bay, in the landing gear fairing. Each system is pressurized by an ACW electric motor driven pump. Normal operating pressure is 3000 PSI. Note: In this model there is only one electrical pump (Plane-Maker doesn’t allow to have more than one).

The hydraulic system supplies:
• Wing flaps
• Spoilers
• Nose wheel steering
• Landing gear extension/retraction

Note: Flight controls are mechanically driven.

Whaaa ... that list looks familiar! In the smaller planes I've flown, most of the systems are either driven mechanically (usually there are cables that connect the control yokes and levers to the aircraft systems, e.g. pulling on the yoke causes the relevant control surfaces to move -- it's that simple) or driven by electric servos, which use electrical power. Since one of the first things you do in starting up an aircraft is to switch on battery power, they usually work.

But in the case of the ATR 72-500, some systems (exactly the one's that I was experiencing problems with) are hydraulically driven, i.e. they depend on pressure on fluids in pipes to transmit movement. That pressure has to come from a hydraulic pump somewhere, which means there is probably a switch in the cockpit to control that.

I got home and fired up the sim again, and found the hydraulic power switch. Turned them on (pressing either switch turns both pumps on, due to the X-Plane limitation mentioned in the manual). I tried moving the yoke and flaps, but it still didn't work. Having a bit more confidence that this was not a software bug, I figured there must be something else I'd missed out. On a hunch I guessed that maybe battery power was not enough to power a hydraulic pump, and looking through the checklist I realised that I hadn't switched on the generators. I turned those on and with the hydraulic pump on, the nosewheel could steer the aircraft! Yay!

I followed the yellow lines to the runway threshold (I find it amazing how pilots are able to keep the nosewheel pretty much on the yellow lines when not only are they sitting at an offset to the center of the plane, but they can't even see the nosewheel from where they sit), tried the flaps and yes they work too. Took off and this time the landing gear came up!

I hadn't figured out how the autopilot works yet so it took a bit of effort to keep the aircraft at a level altitude, but I headed south-ish, and in hardly minutes I was approaching KL International Airport (WMKK). I made a perfect landing at KLIA airport's runway 15L, even with reverse thrust the aircraft didn't have any tendency to go off center (thanks to two engines). Got off at the nearest runway exit, and took the taxiway to the other end of the runway to fly back to Subang. With KLIA's 4km long runways, it takes almost as long to taxi to the other end as it does to fly back to Subang!

Safely parked back at Subang's Skypark Terminal, I shutdown the sim. Lesson learnt: RTFM -- Read the F***** Manual!

I spent the next few days combing through the procedure manual and the aircraft manual, and came up with the following summary sheet, condensing everything into four A4 pages. I also included the minimum speeds for take off and landing (which depend on the total weight of the aircraft):

I had these sheets printed and laminated for easy reference (I might do this for all aircraft from now on). I've attached an A4 PDF and the source document to this note in case anybody wants it.

Second Flight

On my next flight I decided to investigate the autopilot. On all the aircraft I've flown in X-Plane, the autopilot has behaved rather similarly (with the exception of the Cessna 172 on which you only had "altitude hold" and were not able to set a particular vertical speed to ascend or descend to a target altitude). The main differences between the different aircraft so far have been in how the controls are laid out, depending on which auto-pilot system it is emulating.

The ATR 72's autopilot is not much different. Known as the AFCS (which stands for "Automatic Flight Control System") it has its main controls at the top of the cockpit dashboard. The autopilot requires that the inverters are running; the symptom otherwise would be that when selecting any of the controls the display would briefly light up and then go black again.

The autopilot can be used in a few ways. It can be set to fly the aircraft on a specific heading:
  1. Press the "HDG" button (a) to activate heading autopilot.
  2. turn the HDG knob (b) until the course you want to fly is shown in the HDG direction indicator (c).
  3. You can control the maximum bank angle allowed to make turns to achieve this heading by toggling the BANK button (d). The display (e) changes form "HDG SEL LO" (half bank) to "HDG SEL HI" (full bank).
The autopilot can be set to keep the aircraft level at the current altitude:
  1. Press the ALT button (f). The current altitude is reflected in the display ("ALT SEL ...").
The autopilot can be set to climb or descent to a particular altitude:
  1. Press the "ALT" button (f). The current altitude is reflected in the display (g).
  2. Turn the ALT knob (h) until the altitude in the display reflects the altitude you want to reach.
  3. Turn the VS selector (i) until the VS indicator in the display (j).
The above settings will only take effect once the autopilot is toggled active using the AP button (k).

Flying by setting your heading will point your plane in the right direction, but there is no guarantee that you will end up where you intend to. This is because when flying at speed, the aircraft needs quite a distance to turn, and by the time the turn is over you may be a few nautical miles off your intended course. Winds can also cause your aircraft to end up off course. Any discrepancy between the initial heading and the intended heading gets larger the further the aircraft flies.

Therefore, to navigate accurately, the autopilot can make use of VOR (VHF Omnidirectional Range) stations, which are ground-based radio transmitters that act as a "beacon". It transmits a different signal in each directional radial. The aircraft's NAV1 and NAV2 radios can be used to tune into VORs. Turning the (l) and (m) knob on the autopilot control panel changes standby the frequencies, and pressing the (n) and (o) button swaps the standby frequencies with the actual frequencies.

A specific radial can be chose by turning the CRS1 (p) or CRS2 (q) knobs. The currently selected course direction is displayed in the Electronic Horizontal Situation Indicator as (r) and (s).

When the NAV radios are tuned to a particular VOR (and the VOR's signal is within range), the following instruments can be used in the aircraft:

Radio Magnetic Indicator (RMI)
The arrows on the RMI indicate the bearing of the VOR from the aircraft. The yellow needle points to the VOR tuned in to NAV1, and the green needle points to the VOR tuned into NAV2. The two knobs at the bottom must be horizontal to display VOR bearings, if they are vertical they instead display the ADF1 and ADF2 bearings instead. Either needle will point flat to the left if they are not able to tune in to their respective NAVAID.
Distance Measuring Equipment (DME)

This calculates the slant distance from the aircraft to any VOR/DME station that is tuned into by NAV1 or NAV2. The name of the VOR and the distance to it is displayed in the Electronic Horizontal Situation Indicator (see below), ( (a) for NAV1 and (b) for NAV2). The EHSI also displays icons (blue circle (c) for NAV1 and green circle (d) for NAV2) indicating the bearing of the VOR from the aircraft.

VOR Course and Course Deviation Indicator
The aircraft's navigation equipment can tune in to a particular radial from the VOR, and determine the aircraft's offset to the radial. The deviation appears in the Electronic Attitude Director Indicator (see below), as a yellow icon over the 5 dots at the bottom. When the yellow icon (a) is over the center dot, the aircraft is exactly over the radial selected by the CRS1 indicator.

To track a VOR radial manually, you would tune that VOR radial into the CRS selector, and then fly the aircraft at an angle towards the radials path while observing the yellow icon. When the yellow indicator is over the center dot, turn towards the CRS heading. You will now be "tracking" the radial.

The autopilot can automate this manuever for you; simply press the NAV button (t) on the autopilot control panel. The aircraft will fly towards the radial, and once on it, will "track" the radial so that the yellow dot remains always centered. Compared to using the "heading" mode of the autopilot, this has the advantage that the autopilot will correct the effect of winds, etc on the aircraft. The downside is that the aircraft must be within range of the VOR transmitter.

When using the VOR Course setting, remember that the aircraft can be centered on two radials, one "from" the VOR and the other "to". The autopilot will always fly the aircraft towards the heading specified in the CRS setting, so be sure to have the correct one. When reading navigation charts, and flying "to" a VOR, the course we want to fly is the reciprocal of the direction indicated on the radial at the VOR end, which means you will need to add or subtract 180 from it to get the actual course setting.

Finally there is the ILS system. If NAV1 is tuned into the frequency of an ILS localizer and the APP "Approach" button (u) is pressed,, and the aircraft is located within the "beam" of the localizer, the autopilot, will guide the aircraft (regardless of whether HDG or NAV mode is set) so that it is aligned with the localizer (which is usually aimed at the runway approach path). Similarly, when it is crosses the ILS glidescope beam, it will align the aircraft vertically with the beam to bring the aircraft down to the runway on the correct descent angle.

To test out the autopilot on the ATR 72, I planned a flight from Subang (WMSA) to Ipoh (WMKI). My flight would take me from Subang WMSA's runway 33, flying the runway heading to the Batu Arang VOR (VBA 114.7, range 25nm), and then turning on radial 301 towards the SUKAT fixed point. We keep flying this heading (losing VBA after 25nm). Tune CRS1 to Ipoh VOR (VIH, 117.3, range 130nm), and set CRS1 to 184, and when we are centered on this radial, we will know we are at SUKAT. Here, we turn to heading 336. I then set CRS1 to the 040 radial. When we cross this (which would be at the TEPUS fixed point), I turn to heading 040. This leads into the ILS (IPO, 110.5) localizer beam. To intercept the ILS glideslope, I descend to 2400ft at a rate of -800 fpm, at least 11.2 nm before VIH, for final approach to Ipoh WMKI's runway 04.

Flying this way is quite possible -- it's how it used to be done -- but involves a lot of monitoring and fiddling with knobs in-flight. And if you make a mistake, it can take quite a bit of effort to get back on track.

Third Flight

For my third flight, I decided to investigate the Flight Management Computer (FMC). The smaller planes I've flown in had a Garmin GNS-430 in which you could program your flight plan (the set of waypoints you want to travel through), and it would then control the autopilot and navigate the course, changing headings as you reach each waypoint. The ATR72-500 has in its place, a FMC system, which is something like the GNS-430 on steroids.

The ATR72-500 makes use of the standard X-Plane FMC, which I have read is clunky and not so friendly. There is a third party upgrade called X-FMC (http://www.x-fmc.com/) which improves on this. Since it was free, I decided to give it a try and installed the plugin. X-FMC is designed to work most X-Plane aircraft (even those not originally designed with an FMC) and requires a configuration file to specify the aircraft's parameters. The ATR72-500 comes with a config file for X-FMC.

X-FMC is toggled on and off using the F9 key, and the following pop-up appears (being a program add-on, it is not integrated directly into the cockpit):

For this flight I planned a trip from Subang Airport (WMSA) to Penang Airport (WMKP).

The X-FMC interface consists of a keypad and function keys, with menu keys on the left-side and right-side of the display. On startup, I press the FMC key which then displays the IDENT screen, consisting of configuration information. Press the POS INIT key and XFMC asks to key in the reference airport (the airport that I'm are departing from). Either the on-screen keypad or your keyboard (after using the mouse to "dial-in" info on the Garmin GNS-430 this is such a refreshing change!). Press the "REF AIRPORT" once done, and then press the ROUTE key. On the next screen X-FMC expects the destination airport ("WMKP") followed by the ACTIVATE key. A beep sounds and the EXEC button will light up. Pressing it causes X-FMC fills in the heights of both airports from its database.

Before I can specify my actual flight route, I need to know where it starts and where it ends. This depends on the SID (Standard Instrument Departure) and STAR (Standard Terminal Arrival Route) that I plan to use, so we take a quick peek at the airport charts. The northbound SID for WMSA towards WMKP is the SUKAT departure, which leaves you off at the SUKAT waypoint:
Meanwhile, at WMKP, arrivals from the south (NURLA 1A procedure) begin their approach at the NURLA waypoint:

Back in X-FMC, I tap in the following route:

Because I've installed the Navigraph FMS data files, X-FMC is also aware of all the SID and STAR procedures at most airports. Pressing the DEP/ARR button, I click on WMSA DEPT, and specify runway 33, and press EXEC. X-FMC the presents me all the SIDs that depart out of runway 33:

I select SUKAT/SUKAT and press EXEC. Then I press DEP/ARR again, and choose WMKP ARR, runway 04, and press EXEC. Here I choose the NURL1A/NURLA approach procedure.

Flight route done, I press the PERF button next. Here I can set the cruising altitude (8000 ft), and X-FMC will calculate the amount of fuel used (it will also warn if there is insufficient fuel in the aircraft). I can also key in the amount of reserve fuel I need (in 1000s of lbs; with the ATR-72 consuming an average of 200 lbs per hour of flight, keying in 0.2 gives me 1 hour reserves). The Cost Index here is the desired cost index (1-999, high value = no savings). Once all these parameters have been keyed in, pressing the GR WT ADV will result in X-FMC calculating our Ground Weight (in lbs).

On the next screen, THRUSTLIMIT, you can enter the FLEX temp (not sure what this is), and how much take of power to use (TO = full power, TO1 = -5% of full, TO 2 = -10% off full). There are also three Climb profiles to chose from depending on how much thrust to use during initial climb).

On the third screen in the PERF pages, you can choose the amount of flaps to use for take-off (15). Once you've done this, X-FMC calculates your V1, VR, and V2 speeds. You have to acknowledge each of these to complete the pre-flight entry.

X-FMC can also manage vertical navigation, i.e. your altitude at the various stages of the flight. To do this however, it requires an aircraft with auto-throttle, which the ATR-72 does not have. So we will have to manage the vertical navigation aspect of the flight manually.

We're now done programming X-FMC, and can begin our flight. I power up the engines (according to my new checklist, so everything works properly now!).

Prior to take off, we set the flaps to 15 degrees, set the Power Management knob to Take Off (TO) and program the initial autopilot settings:

  • heading = 335 deg,
  • altitude = 6000 ft (we need to cross VBA at or below 6000ft)
  • VS SEL
  • VS = 1000 ft
  • Release the parking brakes, and we're off to taxi to runway 33.

Flaps set to 15 deg, and push the power lever to 100%. Rotate at 136 kt, and we're airborne! With a positive rate of climb, raise the landing gear and set the Power Management knob to CLIMB (CLB). I tap the AP button so the aircraft maintains runway heading and constant climb rate.

Next I press F9 to bring up X-FMC, disable the VNAV, and press the AP button on X-FMC. X-FMC will now manage the auto-pilot settings, by ensuring the aircraft stays on the desired track, and changing the HDG setting at each waypoint.

There are two sets of information displays in X-FMC, the "LEGS" screen shows the upcoming waypoints to the destination, including those of the SIDs and STARs. The "PROG" screen's first page shows the distance to, ETA and estimated fuel at the last waypoint, upcoming waypoint, and destination airport. The second "PROG" screen shows current derived data such as the wind at current altitude, cross wind component, and so on.

Flaps up at 185 kts. Once past VBA, I have to set the autopilot desired altitude to 8000 ft, and also specify a vertical speed so the aircraft will climb.

I did notice that X-FMC initiated the turn rather early. The Garmin GNS-430 in the smaller planes I've flown were able to ensure that the turns were made exactly over the waypoint and the resulting path was pretty much on the outbound track. Eventually though, X-FMC will correct for the mistake and the plane will line up with the desired track, but it does take some time. If there are a series of tight turns to be made, X-FMC tends to make a mess -- in which case it is better for these turns to be executed manually, using FMC as a guide / flight director.

Once we reach 8000 ft I set the Power Management to Cruise (CRZ). When we reach SUKAT, X-FMC programs the autopilot with a new heading, and the aircraft turns by itself.

The turn is still executed a bit too early though. I'm not sure if this is X-FMC related or aircraft related. I'll need to test X-FMC with another aircraft to know for sure.

With a ground speed of almost 270 kts, the ATR-72 500 covers distances much faster than the smaller planes I was used to, so things come up a lot sooner. That makes it's even more important to anticipate and prepare for the next stage.

Looking ahead, we need to begin our descent from 8000 ft at NURLA. The crossing at the next waypoint, part of the STAR, is at MEKAT, and is at or above 3100 ft. The distance between NURLA and MEKAT according to X-FMC is 22 nm. Assuming an airspeed of 200 kts, I used the calculator at http://aerotexas.com/desplan/desplan.php and got:

So about 5 nm from NURLA I pull the power lever back to Flight Idle (around 25%) on my throttle quadrant, and wait till the aircraft slows down, and then bring it up again to maintain a constant speed of 200 kts. At NURLA, X-FMC sets the autopilot on a new heading of 316 deg towards MEKAT, and I set the autopilot's desired ALT to 3100 ft, and vertical speed of -900 ft/m. Now that we are descending, the power lever has to be pulled back further to maintain a descent speed of 200 kts.

After MEKAT, I need to descend from 3100 ft to 2500 ft to enter the ILS's final approach path. The distance between the two points is 5nm, which give us a descent rate of 400 fpm assuming and airspeed of 150 kt. Therefore we need to slow the aircraft further.

As we near WMKP, I set the NAV1 to WMKP's runway 04 ILS frequency 109.9 and bring the flaps down to 15 deg. The Power Lever is set to Take Off (TO) again, in case we need to go around and require maximum power.

Darn, X-FMC has again turned too early ... leaving me way to the right of the approach path. I should have probably disabled X-FMC and done the last turn manually. Anyway, I press the AP button on X-FMC to disengage its control over the autopilot, and press F9 to hide the pop-up panel. The aircraft is still running on autopilot, flying the last heading set by X-FMC. To get on the correct path, I turn the HDG knob about 20 deg to the left. I also press the APP button, so that the aircraft will intercept the ILS localizer and turn onto the correct flight path.

I do a quick review of the ILS landing chart (Love the note "Butterworth WMKB. Do not mistake for WMKP"!).

I check my notes and at 37,000 lbs and 30 deg flaps, my final approach speed should be 95kts. Shortly, the aircraft captures the ILS glideslope and begins to descend.

Visibility outside is poor (WMKP METAR reports 4000m):

At 1000 ft, the runway is finally in sight. I switch off the autopilot and increase flaps to 30 deg to reduce speed further. The landing gear is lowered.

Air speed is around 120 kts ... but I'm now slightly below the ILS glideslope. Raise the nose a little and speed drops to about 100 kts. The runway is approaching fast! I'm slightly off the centerline but it's too late to fix that. The radio altimeter calls out 30 ft ... I pull the power lever to Flight Idle and raise the nose to flare.

Touchdown! I got a "good landing" score from the Landing Speed add-on (it "grades" the quality of your landings your landing based on how smooth it is). I step on the brakes and engage reverse thrust and the aircraft slows down dramatically (reverse thrust is probably not necessary given how long the runway is but it's kind of fun to engage).

I vacate the runway via exit C ...

... and head back towards the terminal building.

Aircraft is parked at an open stand -- no aerobridge for the ATR72-500 -- and engines shutdown. Doors opened and we're done!


The ATR-72 500 is a great plane ease into flying airliners from General Aviation aircraft. And two engines are definitely better than one!

  1. Occasionally, when making a turn under X-FMC, the aircraft turns the long way around, i.e. for a simple 90 degree turn to the left, the aircraft will instead make a 270 degree turn to the right. The X-FMC guys say they just set the heading on the aircraft's autopilot, how it turns is up to the aircraft, so it's not something X-FMC can fix. I'll need to test X-FMC on another aircraft to be sure if this is just an issue with the ATR-72 500.