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FLIGHT SIMULATOR X - Notes from a virtual Air Traffic Controller and occasional virtual pilot

 

Page 1

The down-side of ATC sessions
Ways to mess up a game
Look before you leap
Sequence and simple checks for a flight

Page 2

To Take-off, Perchance to land
Watch your speed
Circuits, Flips, and Trips
Show me the way

Page 3

That dial is going backwards
On approach
Two white, two red, three green
Come on down

Page 4

Standard words and phrases
Commonly used aviation abbreviations
Murphy's Laws 1 - 4
Radio/Mic Check

Page 5

George is flying
Who are you?
Are we there yet?
Landing delays

Page 6

The Phonetic Code
Numeric Pronunciations
Clock Headings
Worded compass headings


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THAT DIAL IS GOING BACKWARDS!

When the altimeter goes counter clockwise it can mean only one thing - you are losing height.  If that is the case, and descent is intentional, then you are almost certainly proving the truism "What goes up, must come down" and you will be landing soon.  It has been said that the four most useless things to a pilot are: Runway behind you; Altitude above you; Fuel on the ground; and 1 second ago!  The chances are that most of us do not realise just how many ways there are to get it wrong.  Let me start with a few:  Lose height too quickly and you land short of the runway, or hit it too hard.  Lose height too slowly and you overshoot or run out of tarmac.  Approach too slowly and you stall.  Approach too fast and the 10000 feet of asphalt is all too soon behind you...  There are so many ways to get it wrong.  Oh yes, remember to put the landing gear down as well.

 

The basics of landing a plane are pretty much the same for all aircraft but each different type of aircraft will behave its own way, with many variations.  It is when you move outside those variations that you'll come to grief.  But stick with simple concepts and make use of any assistance you can and it gets easier.  Try to get the aircraft lined up with the runway well in advance, it is easier to deal with other things if the plane is already pointing at the runway.

 

Ideally the plane should be at about 300 feet altitude for every mile away from touch down (with a 3 degree glideslope that is) so try to make sure the plane is at a suitable height to descend safely.  Make sure you know how to operate the brakes, flaps, spoilers (speed brakes) and reverse thrust.  Be aware of the runway length - trying to land a B747 on a 5000 feet runway will always be 'challenging'.  If the airfield is equipped with landing aids, use them, it is not a sign of weakness or poor piloting skills.  As a rule I have found that the best pilots make use of any help they can get.  The use of ILS/DME or GPS allows a pilot to 'see' a runway well before it comes into visual range.  I have found that almost without exception a pilot who knows or asks for details of navaids like ILS is far more likely to make a successful landing.  Take-off is optional, but landing is mandatory, so don't be afraid to reject a landing if it is not going well. 

 

I have lost count of the amount of times I've seen awful landings because the pilot just 'had' to get down.  On the other hand I tip my hat to the few pilots who know better and 'go around' or call out "Missed approach", you can always have another go.  As ATC a missed approach is inconvenient, but not as inconvenient as a runway blocked by a wrecked aircraft!  So my last word here is know how to TOGA (Take-off/Go around).  There are several reasons why you might elect to go-around.  Perhaps that turn onto finals was not tight enough or it was planet sized and you are not well lined up with the runway.  Perhaps you are too high to make a safe, controlled approach.  Perhaps you are coming in too hot, that is, too fast.  Perhaps there has been a runway incursion, that is, something is on the runway.  Perhaps you feel that the slow light aircraft you were following is now too close and may not clear the runway in time.  Perhaps 100 feet up you make a last anxious check for 3 greens only to discover you never did select 'gear down'.  Maybe the Tower spots something you didn't and tells you to go-around.

 

Maddening as that might be, you can only land well once.  But unless fuel or time is a concern, you can always have another go at approach.  The missed approach procedure varies from place to place but a general guide would be to apply power, stop your descent, start to climb, raise the landing gear and select a suitable flap setting.  Stay on runway heading more or less, climb to about 2000 feet or the circuit height, and contact the Tower for further instructions.


ON APPROACH

The standard approach to most airfields is a 3 degree angle glideslope, this angle covers the majority of airfields although there are some notable exceptions, London City (EGLC) for example has a glideslope of 5.5° (due to tall buildings, airspace restrictions and noise abatement).  The tables below were calculated using trigonometry and although they may initially appear complex the maths involved are quite simple, the tables have uses for both pilots and controllers alike. 

 

The columns in green denote distance in nautical miles, statute miles, and kilometres.  The row in yellow denotes the approach angle; I have highlighted the 3 degree column for convenience.  The rows and columns in blue line up approach angles versus distance, and in combination read off altitude.  The altitudes have been rounded up or down to the nearest 100 feet.  An aircraft approaching a runway that has a standard 3 degree glideslope needs to be (rounding figures off to the nearest hundred feet) at a height of 300 feet per mile distance from touchdown.  (In truth the true figure is 319 feet per mile for a 3 degree glideslope but few altimeters will read that precisely!)  So for example a plane making a normal approach to an airfield with a 3 degree glideslope should be at:  1600 feet 5 miles out; 3200 feet 10 miles out; 4800 feet 15 miles out, and so on.

 

Distance

Approach angle (degrees)

Dist.

Approach angle (degrees)

km

sm

nm

2.5

2.6

2.7

2.8

2.9

3.0

3.1

3.2

3.3

3.4

3.5

nm

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

1.9

1.2

1

300

300

300

300

300

300

300

300

300

400

400

1

200

300

300

400

400

500

500

600

600

3.7

2.3

2

500

600

600

600

600

600

700

700

700

700

700

2

400

500

600

700

800

1000

1100

1200

1300

5.6

3.5

3

800

800

900

900

900

1000

1000

1000

1100

1100

1100

3

600

800

1000

1100

1300

1400

1600

1800

1900

7.4

4.6

4

1100

1100

1100

1200

1200

1300

1300

1400

1400

1400

1500

4

800

1100

1300

1500

1700

1900

2100

2300

2600

9.3

5.8

5

1300

1400

1400

1500

1500

1600

1600

1700

1800

1800

1900

5

1100

1300

1600

1900

2100

2400

2700

3000

3200

11.1

6.9

6

1600

1700

1700

1800

1800

1900

2000

2000

2100

2200

2200

6

1300

1600

1900

2200

2600

2900

3200

3500

3800

13.0

8.1

7

1900

1900

2000

2100

2200

2200

2300

2400

2500

2500

2600

7

1500

1900

2200

2600

3000

3400

3700

4100

4500

14.8

9.2

8

2100

2200

2300

2400

2500

2500

2600

2700

2800

2900

3000

8

1700

2100

2500

3000

3400

3800

4300

4700

5100

16.7

10.4

9

2400

2500

2600

2700

2800

2800

3000

3100

3200

3200

3300

9

1900

2400

2800

3300

3800

4300

4800

5300

5800

18.5

11.5

10

2700

2800

2900

3000

3100

3200

3300

3400

3500

3600

3700

10

2100

2700

3200

3700

4300

4800

5300

5900

6400

20.4

12.7

11

2900

3000

3200

3300

3400

3500

3600

3700

3900

4000

4100

11

2300

2900

3500

4100

4700

5300

5800

6400

7000

22.2

13.8

12

3200

3300

3400

3600

3700

3800

3900

4100

4200

4300

4500

12

2500

3200

3800

4500

5100

5700

6400

7000

7700

24.1

15.0

13

3400

3600

3700

3900

4000

4100

4300

4400

4600

4700

4800

13

2800

3400

4100

4800

5500

6200

6900

7600

8300

26.0

16.1

14

3700

3900

4000

4200

4300

4500

4600

4800

4900

5000

5200

14

3000

3700

4500

5200

6000

6700

7500

8200

8900

27.8

17.3

15

4000

4100

4300

4500

4600

4800

5000

5100

5300

5400

5600

15

3200

4000

4800

5600

6400

7200

8000

8800

9600

29.7

18.4

16

4200

4400

4600

4800

4900

5100

5300

5400

5600

5800

5900

16

3400

4200

5100

5900

6800

7700

8500

9400

10200

31.5

19.6

17

4500

4700

4900

5000

5200

5400

5600

5800

6000

6100

6300

17

3600

4500

5400

6300

7200

8100

9000

10000

10900

33.4

20.7

18

4800

5000

5200

5300

5500

5700

6000

6100

6300

6500

6700

18

3800

4800

5700

6700

7700

8600

9600

10500

11500

35.2

21.9

19

5000

5200

5400

5600

5800

6000

6300

6400

6700

6900

7000

19

4000

5000

6000

7000

8100

9100

10100

11100

12100

37.1

23.0

20

5300

5500

5700

6000

6200

6400

6600

6800

7000

7200

7400

20

4200

5300

6400

7400

8500

9600

10600

11700

12800

38.9

24.2

21

5600

5800

6000

6200

6500

6700

6900

7100

7400

7600

7800

21

4500

5600

6700

7800

9000

10100

11200

12300

13400

40.8

25.3

22

5800

6100

6300

6500

6800

7000

7200

7500

7700

7900

8200

22

4700

5800

7000

8200

9400

10500

11700

12900

14100

42.6

26.5

23

6100

6400

6600

6800

7100

7300

7600

7800

8100

8300

8500

23

4900

6100

7300

8500

9800

11000

12200

13500

14700

44.5

27.6

24

6400

6600

6900

7100

7400

7600

7900

8100

8400

8700

8900

24

5100

6400

7600

8900

10200

11500

12800

14100

15300

46.4

28.8

25

6600

6900

7200

7400

7700

8000

8200

8500

8800

9000

9300

25

5300

6600

8000

9300

10600

12000

13300

14600

16000

km

sm

km

Altitude (ft) above runway height

nm

Altitude (ft) above runway height

 

In an ideal situation a plane making a precision ILS approach should be established on the localiser, and better still close to the glideslope, at a range of about 7 miles (and at a height of 2200 feet).  At this range or point, often known as the final approach fix (FAF), a plane would then be handed over to the Tower controller for landing clearance.  In theory the plane should be more or less lined up on the runway and at the correct height at this point.

 

From a pilots perspective making an approach to a runway equipped with VOR/DME, or ILS/DME (with 3 degree glideslope), the pilot needs to be at a height (above the runway threshold) of 300 feet per mile from touchdown.  So, for example, an approaching plane 5 miles out at a height of 2000 feet is too high and will need to increase the rate of descent.  (As a rule I have found that if a plane is more than twice the desired altitude for a given distance landing is still possible but ‘chasing the glideslope’ presents problems that only the better pilots can resolve.)  An approaching plane 10 miles out at a height of 2500 feet is too low and will have to decrease the rate of descent, while not ideal, this situation is preferable to being too high.  An approaching plane using a VOR/DME approach can still make an accurate approach by referring to the DME readout and using the distance reading to gauge the ideal height to be at.  Obviously, if ILS is being used the instruments provide further clues as to the approach profile.

 

Most autopilots have an 'APP' (Approach) button.  Using this function the autopilot can fly the approach for you.  But, there is a catch, the APP function cannot do ALL the flying for you:  The plane must be within 30 or so degrees of the runway heading, and the farther out you are the better; The ILS frequency MUST be entered into the Nav 1 radio; You must set the course correctly on the instrument or autopilot panel; You must switch on the APP function underneath the glideslope; And you must disengage the autopilot just before landing.  The approach function on the autopilot is NOT the same as autoland.  Also, autothrottle (if used) must be disengaged before landing as well.

 

It should be pointed out now that altimeters have different settings.  The first is what is known as QFE that is the altimeter setting used so that it reads zero at the airfield/runway itself.  This setting may be used but it is worth noting that by default FSX sets the altimeter to QNH which is the altimeter setting for the atmospheric pressure at sea level.  So if the airfield is 500 feet above sea level and QNH is set, the altimeter will read 500 feet.  Conversely, if the altimeter is set to QFE it will read zero at the same airfield.  In other words, QNH and QFE are different settings and will give you different altimeter readings at a given location, unless you are landing at sea level.

 

(Two scales are used with altimeters: Inches of Mercury; and Millibars.  (To add to the confusion barometric pressure is sometimes expressed in Hectopascals, which are the same as millibars apart from the name!)  All scales are in widespread use though in reality inches of Mercury is largely confined to North America.  The standard setting is 29.92 inches, or 1013.2 millibars, this measurement being the worldwide average atmospheric pressure.  It is common for aircraft to reset their altimeters to this standard setting so that all aircraft are using the same reference for altitude, this setting can be particularly critical when aircraft are flying along airways for example.)


TWO WHITE, TWO RED, THREE GREEN...

Most airfields have some sort of visual landing aid available such as PAPI, APAPI, VASI, or LITAS lights.  Perhaps the most common visual landing aid in the UK and many other countries is PAPI (Precision Approach Path Indicator).  This system allows a remarkably accurate approach to be made if you follow the lights and adjust your descent accordingly.  PAPI is a single row of 4 lights, usually on the left side of the runway, next to the touchdown zone.  These lights can often be made out from up to 20 miles away, day and night, and are also visible in all but the worst weather.  The indications are simple and give you instant clues of how to adjust your descent profile.

 

PAPI indication

Meaning

Action required

llll

Too low

Level off or climb

llll

Slightly low

Slightly decrease rate of descent

llll

Correct approach angle

Maintain current approach profile

llll

Slightly high

Slightly increase rate of descent

llll

Too high

Increase rate of descent

 

If you make an accurate, precise approach using the PAPI light system your landing should be well within the touch down zone, on target with the fixed distance runway markers that are usually about 300 metres from the runway threshold.  As if to emphasise the accuracy of PAPI, the difference between a correct approach angle and being slightly high or low is just one fifth of a degree.  This equates to just 100 feet at five miles range.

 

Other approach lighting systems work with similar principles but are less accurate, the general rule being that if you see white AND red indications you are more or less on the correct approach angle.  In any of these systems used a general rule is: All reds = too low, All whites = too high.  I have included an account of these lights since many new FSX virtual pilots do not know what they are for, for all landings they are almost indispensable.


APAPI (Abbreviated Precision Approach Path Indicator) is a simplified PAPI system often found at smaller airfields.  Instead of a row of 4 lights APAPI uses just two lights in a row with fewer overall indications.  The level of accuracy of APAPI is less than that of PAPI though it is still a useful approach aid.  In practice it is still more accurate than VASI.

 

APAPI indication

Meaning

Action required

ll

Too low

Level off or climb

ll

Correct approach angle

Maintain current approach profile

ll

Too high

Increase rate of descent


Another type of visual landing aid is VASI (Visual Approach Slope Indicator).  This is a simpler, less accurate system of lights that form two bars or rows of lights adjacent to the landing zone, one in front of the other.  As opposed to PAPI, VASI has only three indications that are illustrated below.  VASI was in widespread use many years before PAPI appeared on the scene and although much better than no approach aid at all the use of VASI is slowly being phased out.  While there are standards and criteria to be met by all landing aid lighting systems you would have to check airfield specific charts and information to find out what system is in use at a given airfield.

 

VASI indication

Meaning

Action required

llll

llll

Too low

Level off or climb

llll

llll

Correct approach angle

Maintain current approach profile

llll

llll

Too high

Increase rate of descent


There are 4 other variations of approach lighting, only 2 of which I have seen in FSX…

 

PVASI (Pulsating Visual Approach Slope Indicator) gives a pilot 4 indications on approach.  These are:  Steady white = correct approach; steady red = slightly low; pulsing white = too high; pulsing red = too low.

 

LITAS (Low Intensity Two-colour Approach System) is a simplified and cheaper VASI with low wattage lamps.  Instead of 2 rows of lamps there are just 2 lamps but the indications are the same as VASI.  The low wattage lamps mean that it is less visible and has a shorter range than other systems but in practice it has been found to be visible in daylight in all but direct sunlight.

 

Another system to mention in passing.  (Three-colour Visual Approach Slope Indicator) may be encountered at some Russian and Ukrainian airfields and some other isolated locations.  Amber = too high; Green = correct approach angle; Red = too low.  This sounds simple but in practice has a major flaw – when slightly low the red and green can mix at certain angles and can look like yellow (mix red and green on a colour pallete and they make yellow).  The danger being that it may give the pilot the impression that he is too high when in fact he is already too low, the danger of this should need no further explanation!

 

To further add to the variety, there is another system called TVASI used in Australia.  It is more complex than any other system in use but is broadly comparable to PAPI.

 

Lastly, Three greens is a reference to aircraft with retractable landing gear…  Focussing on the approach lights may distract you from checking that the undercarriage is down!


COME ON DOWN

Still on the subject of approach and landing, the table below is another of those seemingly dry bits of data that can be off-putting.  However, a glance at the tables will hopefully make you realise that much about aviation can be boiled down to numbers and in this case the numbers can be useful.  If you have a target or preferable approach speed, and you know the glideslope angle, you can quickly read off required rate of descent.  The standard 3 degree glideslope has been highlighted in both cases to aid clarity.  So, for example, if your plane has an ideal approach speed of 70kts and the 3 degree glideslope applies, your rate of descent needs to be about 400 feet per minute.  Another example, you decide to aim for an approach speed of 130kts so your rate of descent will need to be 700 feet per minute.

 

App. angle

Approach speed (Ground speed, kts)

Degrees

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

2.5

200

300

300

400

400

400

500

500

600

600

700

700

800

800

900

900

2.6

200

300

300

400

400

500

500

600

600

700

700

700

800

800

900

900

2.7

200

300

300

400

400

500

500

600

600

700

700

800

800

900

900

1000

2.8

300

300

400

400

500

500

600

600

700

700

800

800

900

900

1000

1000

2.9

300

300

400

400

500

500

600

600

700

700

800

800

900

900

1000

1000

3.0

300

300

400

400

500

500

600

600

700

700

800

900

900

1000

1000

1100

3.1

300

300

400

400

500

600

600

700

700

800

800

900

900

1000

1100

1100

3.2

300

300

400

500

500

600

600

700

700

800

900

900

1000

1000

1100

1100

3.3

300

400

400

500

500

600

700

700

800

800

900

900

1000

1100

1100

1200

3.4

300

400

400

500

500

600

700

700

800

900

900

1000

1000

1100

1200

1200

3.5

300

400

400

500

600

600

700

800

800

900

900

1000

1100

1100

1200

1300

Rate of descent (ft/min)

App. Angle

Approach speed (Ground speed, kts)

Degrees

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

2.0

200

200

300

300

300

400

400

400

500

500

500

600

600

600

700

700

2.5

200

300

300

400

400

400

500

500

600

600

700

700

800

800

900

900

3.0

300

300

400

400

500

500

600

600

700

700

800

900

900

1000

1000

1100

3.5

300

400

400

500

600

600

700

800

800

900

900

1000

1100

1100

1200

1300

4.0

400

400

500

600

600

700

800

900

900

1000

1100

1100

1200

1300

1400

1400

4.5

400

500

600

600

700

800

900

1000

1000

1100

1200

1300

1400

1400

1500

1600

5.0

400

500

600

700

800

900

1000

1100

1200

1300

1300

1400

1500

1600

1700

1800

5.5

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

6.0

500

600

700

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

Rate of descent (ft/min)

 

From an ATC perspective the information above may be useful as well.  When offering a pilot assistance on approach, or simply monitoring a plane, the track of the aircraft is obvious enough and using the radar displaying the ILS centreline it is possible to tell a pilot how far away he is as well as whether he is left or right of centreline.  Using the data table in conjunction with other information about the aircraft it is thus possible to advise the pilot: speed; distance; left/right of centreline; too high/too low... important information necessary to make a successful landing.

 

Something seldom heard in FSX is a radar assisted approach which replicates a what is known as PAR (Precision Approach Radar) whereby the controller 'talks down' an aircraft to the point where the pilot can land himself, for example in fog or other limited visibility conditions.  On several occasions I have offered a radar assisted approach to pilots (though no one has ever asked for it) and in all cases it has made a landing possible where prior attempts had failed for whatever reason.


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© Derek Haselden 2017

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