ppl_03_e2
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ID: 3658
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 13: PRACTICAL NAVIGATION
Track Error (°) |
= |
Distance Off Track (nm) × 60 |
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Distance Along Track (nm) |
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Track Error (°) |
= |
2 × 60 |
= 5° (by approximate mental arithmetic) |
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23 |
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So, changing heading by 10° to starboard, from 348° (M) onto 358° (M) should take you directly to Hawarden.
The Closing Angle Method of Correcting Track Error.
If the wind forecast has been inaccurate, while you have accurately held your planned heading, there is a further method of heading correction you may use, if you find yourself off track. You can, if you wish, use a method which assesses corrections relative to your destination only. This method of heading or track error correction is called the Closing Angle Method.
In the Closing Angle Method, an assessment of the amount of correction to be applied is based on the proportion of the total leg distance already flown, and the closing angle to the destination, as illustrated in Figure 13.12.
If, during a flight from A to B, a pilot pinpoints himself off track at a position X, he must establish two things.
•The closing angle with the destination (or next turning point).
•The proportion of the total leg distance already covered.
Figure 13.12. The Closing Angle Method of Track Error or Heading Correction.
In Figure 13.12, the pilot has estimated (using drift lines or the 1 in 60 Rule) that the closing angle with his destination, B, is 5°. He has established, too, that he has flown ¼ of the total leg distance.
Using the Closing Angle Method of heading correction, the pilot simply inverts the fraction of the leg-distance already flown (so ¼ becomes 4), and multiplies the inverted fraction by the closing angle. Therefore, in Figure 13.12, the heading correction to arrive at B from X is 4 × 5° = 20° to port. For subsequent track checks, figures used must be relative to the previous fix - see page 248.
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Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 13: PRACTICAL NAVIGATION
Let us try a practical example of using the Closing Angle Method of track-error and heading correction.
If, after spotting your third checkpoint, the lake at Ellesmere, you pinpoint your position as being 2 miles to the left of your desired track, what would be the heading to steer to fly directly to Hawarden?
Figure 13.13. Two miles to the left of track at Ellesmere.
You know from your flight planning that the lake at Ellesmere is 33 nautical miles (nm) along the total leg distance of 49 nm from Ludlow to Hawarden. That is 2/3 of the leg distance, as near as makes no difference.
Being 16 nm from Hawarden, and using the 1 in 60 Rule, you estimate your track error with respect to Hawarden (in other words, your closing angle to get to Hawarden) as being 8°.
Track Error (°) |
= |
2 × 60 |
= 8° (by approximate mental arithmetic) |
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16 |
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As with drift angle lines, a closing angle line originating from the turning point/ destination makes finding the closing angle quicker and easier. In accordance with the closing angle method, you multiply 8° by the inverse of the fraction 2/3 in order to obtain the heading correction that you need to make, to track directly to Hawarden.
Heading Correction (°) = |
8° × 3 |
= 12° |
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2 |
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Consequently, you alter heading by 12° to starboard and, if you had been steering 348° (M) up to that point, you would steer 360°(M).
This technique is also called the New Track Reference technique, as it puts the aircraft on a new track (hopefully fairly close to the original) to the turning point. If subsequent heading checks are carried out on the same leg, the calculation is slightly modified: the change in closing angle since the previous fix is multiplied by the inverse of the proportion of track flown since the previous fix. You should note that all the methods of making heading correction that you have learned in this chapter are approximations, but that for VFR mental dead reckoning, over relatively short
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ID: 3658
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 13: PRACTICAL NAVIGATION
legs, say, less than 100 nm, the methods are accurate enough for successful visual navigation.
Revision of ETA.
It has been mentioned several times that any elapsed time errors that are noted at the half way point along a leg are doubled in order to obtain the error at the next turning point or destination. For instance, if you are 2 minutes early at the mid-way point, you will arrive at destination 4 minutes early.
In order, however, to revise ETA based on an elapsed time error that you might record at any point along the leg of a navigational flight, you can use the inverse fraction operation from the closing angle method that you have just learned. For instance, if you observe that you are 2 minutes late at a checkpoint, 2/3 of the way along a leg, you multiply the elapsed time error by the inverse of 2/3, that is, 3/2, which tells you that you will be 3 minutes late on completion of the leg. Likewise if you are 11/2 minutes early at the 1/4 leg point, you will 4/1 × 11/2 = 6 minutes early when the leg is completed.
Any elapsed
time error at the half-
way point along a leg
is doubled to obtain the time error on completion of the leg.
ARRIVAL AT HAWARDEN.
After making the heading correction at Ellesmere Lake, and with the visibility being excellent, you soon pick out the town of Wrexham, in front of you in the distance. Being happy with your track and timings, and knowing that with a tail wind component, you should arrive at Hawarden in about 9 minutes, you inform whatever station you have been speaking to, that you are changing frequency to the Hawarden frequency which is entered in your flight log. You have studied the Hawarden airfield plan during the flight planning stage (See Page 214) and have a copy of it on your knee pad, so you already have the basic information about the airfield, such as runway orientation, landing distances available, circuit height, noise restrictions etc. You are also aware from your pre-flight study of the 1:500 000 chart that Hawarden provides a full air traffic control service and will, therefore, provide you with information and instructions for the approach to land. The aerodrome even has a VHF Direction Finding facility, if you should need to use it.
Hawarden ATC will tell you how they wish you to join the circuit; but if you were joining an airfield without full air traffic control, you might wish to consider joining the circuit pattern by adopting the standard overhead joining method described in the Civil Aviation Authority’s Safety Sense Leaflet
No 6: ‘Aerodrome Sense’, and in Volume
1, Air Law, in this series of manuals.
Before setting up your approach to |
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Hawarden, assure yourself |
beyond |
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doubt that you have identified the correct |
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aerodrome, and do not put your chart |
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away until you are absolutely sure that |
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it is indeed Hawarden that |
you are |
Figure 13.14. Arrival at Hawarden. |
approaching. |
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Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 13: PRACTICAL NAVIGATION
In visual
navigation, most of the
navigating should be done on the ground before the flight.
AFTER THE FLIGHT.
After your flight, when you are back at home or in the club house, do not fail to analyse the flight in detail. You can learn an awful lot from considering how the flight went: what worked well and what was not so good. Did you fly the headings and airspeeds accurately enough? Did you hold your altitude well? Did you carry out the HAT and FREDA checks at the right time, and regularly enough? Were your RT exchanges timely, proficient and effective? Did you monitor the drift and wind speed effectively at the start of each leg? Did you react correctly and effectively to any track or timing errors? And so on.
You will almost certainly conclude that most of the navigating needs to be done on the ground before you even take off.
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ID: 3658
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 13: PRACTICAL NAVIGATION QUESTIONS
Representative PPL - type questions to test your theoretical knowledge of Practical Navigation.
The following questions are based on a visual cross-country flight that you are planning to make from Cambridge aerodrome (EGSC) (N5212 E00019) to Fenland aerodrome (EGCL) (N5244 W00002), via the village of Elmswell (N5214 E00054) and the railway junction at Reedham (N5233 E00133). You plan to use Peterborough Sibson (EGSP) (N5233 W00023) as your destination alternate.
First of all, draw your route on your own ICAO 1:500 000 of Southern England and Wales, choosing suitable visual checkpoints. Draw 10° drift lines from your airfield of departure, destination airfield and turning points, as you think fit. When you have drawn your route, compare it with the route at Appendix 1, at the end of the book, then answer the following questions.
The answers to these navigation questions are given in Appendix 2, at the end of the book, either within the completed Flight Log, or beneath the Flight Log.
Having confirmed from the Met Report that the weather will be good for the whole flight, with a cloud base of 4000 feet, you begin your flight planning. The magnetic variation in the region of your flight is 2° West. After obtaining the Regional Pressure Setting (RPS) of 1011 millibars, you elect to fly the whole route at Flight Level 35 as, at that level, you will not pass through any of the Military Aerodrome Traffic Zones or Aerodrome Traffic Zones which lie on or near your route, and calculate that, at your planned Indicated Airspeed, your True Airspeed at Flight Level 35 will be 100 knots. The wind at that level is forecast to be 230° (T) at 15 knots.
1.Measure the True Track and distance, and calculate the Magnetic Heading and Ground Speed for the first leg from Cambridge to Elmswell, and enter the values in your Flight Log.
2.Measure the True Track and distance, and calculate the Magnetic Heading and Ground Speed for the second leg from Elmswell to Reedham, and enter the values in your Flight Log.
3.Measure the True Track and distance, and calculate the Magnetic Heading and Ground Speed for the third leg from Reedham to Fenland, and enter the values in your Flight Log.
4.Choose an appropriate Safety Altitude for each leg and enter them in your Flight Log.
5.How long will it take you to fly from overhead Cambridge (EGSC) to your first turning point at Elmswell?
6.How long will it take you to fly from overhead Elmswell to your second turning point at Reedham?
7.How long will it take you to fly from overhead Reedham to your destination at Fenland (EGCL)?
8.How long, after passing overhead Elmswell, and turning onto your new heading for the second leg, will you reach your visual checkpoint at the disused airfield of Thorpe Abbots?
9.On the third leg, after turning at Reedham, what will be the time lapse before crossing the railway line running from Kings Lynn to Ely?
10.How much fuel will your aircraft consume to complete the whole route, if its fuel consumption rate is 10 US gallons per hour? (Round up your calculations to the nearest whole gallon.)
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Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 13: PRACTICAL NAVIGATION QUESTIONS
11. You bear in mind the following considerations concerning fuel consumption:
a. Time to complete route: ? b. Planned diversion time from destination to alternate: 12 mins. c. 10% Contingency: ? d. Holding Fuel: 8 US gallons. e. Minimum Reserve (Landing) Fuel: 5 US gallons. f. Fuel Consumption Rate: 10 US gallons per hour.
What, then, is the minimum fuel you must carry for the planned flight? Round up each element of the calculation to the nearest gallon.
12.On the second leg, after 17 nm, you fix your position over the centre of a town you identify as Harleston. Assuming you have flown your planned compass heading from Elmswell and have made no obvious errors in your navigational calculations, what should be your heading correction to reach the next turning point at Reedham?
13.If, on the third leg, you were thee minutes late on crossing the Kings Lynn – Ely railway line, what would be your approximate timing error on arrival at Fenland, if you maintained your planned airspeed?
14.At Shipdham, maintaining Flight Level 35, you contact the Marham MATZ controller to inform him that you will be passing above the MATZ. He gives you the Marham aerodrome QFE of 1008 which you decide to set on your altimeter while you overfly the MATZ. How will you altimeter reading change as you set the QFE?
15.If, on the third leg, from a position where your planned track crosses the Kings Lynn to Ely railway line, you were to elect to divert to Peterborough Sibson (EGSB), what would be your new Magnetic Heading, your Ground Speed and time taken to arrive at your alternate?
16.Deciding, however, to fly straight on to Fenland, you are informed, when you make your joining call, that Fenland are using Runway 18 and that the surface wind is 210/15. What will be the cross wind component on Runway 18?
17.On the third leg, where your planned track crosses the Kings Lynn to Ely railway line, you find yourself 2 nm to the right of track, on the Southern edge of Kings Lynn. You see from the drift lines from Fenland aerodrome, that you drew on your map during flight planning, that your track error with respect to your destination of Fenland is 10°. You have held a constant, accurate heading since leaving Reedham so you deduce that the wind must have backed and become more of a Southerly wind. Quickly assessing that you have flown about £\R of the leg distance from Reedham to Fenland, you use the Closing Angle Method of track error correction to calculate the heading correction you need to make to fly direct to Fenland. What heading correction would you make?
18.If your aircraft were fitted with a VOR, ADF, and DME, as well as a standard VHF voice communications radio, which radio navigation aid might you elect to use to help you track towards Fenland?
19.What is the circuit direction for Runways 26 and 18, at Fenland? Consult the airfield information for Fenland, at Appendix 3.
20.On the third leg, as you approach the Marham MATZ, you decide to comply with the Quadrantal Rule, even though your are flying VFR. You elect, therefore, to use a Flight Level which corresponds to your magnetic track, in accordance with the Quadrantal Rule. What is the lowest Flight Level you can use?
21.When might you expect an Aerodrome Flight Information Service to be available from Fenland? Consult the airfield information for Fenland, at Appendix 3.
22.If you had diverted to Peterborough/Sibson, and received AFIS information that the surface wind there was 210/08, which runway would you expect to be in use, what would be the circuit height and direction, and what would you have to be particularly aware of, on the approach? Consult the airfield information for Peterborough/Sibson, at Appendix 3.
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CHAPTER 14
THE LOST PROCEDURE
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CHAPTER 14: THE LOST PROCEDURE
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ID: 3658
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 14: THE LOST PROCEDURE
INTRODUCTION.
There is a long standing aviation joke that pilots are never lost, just temporarily uncertain of position. But being lost is quite different from being temporarily uncertain of position. If a pilot has missed a checkpoint but manages to determine his position again, relatively quickly, he is not lost. But not being able to discover where one is, when airborne, and realising that one is lost, can be quite a frightening experience. Consequently a pilot needs to have a plan of action in case he one day gets lost.
In the lesson on practical navigation, you “flew” an example route from Oxford to Hawarden via Ludlow. You will remember that, on the second leg, one of the checkpoints, the road/railway bridge, South West of the disused airfield at Condover, was not seen, because the feature was not distinguishable enough, and the aircraft flew right over the top of it. The advice we gave, in that case, was to maintain the planned heading and speed and look for the next checkpoint, at the planned time. In those circumstances, until the next feature was seen, the pilot could be said to be temporarily uncertain of position, because he had not had a position fix for 8 minutes. If the next feature, the disused airfield at Montford Bridge, had not been seen, then the pilot would have missed two, planned visual fixes and would be lost.
If you practise diligently the flight planning and navigation skills that you will learn during your pilot training, it is improbable that you will get lost on such a short leg as the leg from Ludlow to Harwarden, unless the visibility is very poor. If, however, you are forced to the conclusion that you are lost, you must have in mind a logical plan of action to take, in order to re-establish your position. This chapter covers the essentials of the action to take when lost. We will call it the lost procedure.
Above all, having come to the conclusion that you are lost, do not fly on aimlessly; put into action the lost procedure.
REASONS FOR GETTING LOST.
Inaccurate Flying.
The most common reason why a pilot gets lost in a light aircraft is inattention to flying accurate headings, speeds and levels. In VMC, if the correct heading is flown, at the planned airspeed and altitude, and correct allowances are made for forecast wind, magnetic variation and compass deviation, there should be no reason why the aircraft should deviate from track far enough to become lost. So, the chances are that the reason for getting lost will be an error in one of the aforementioned parameters.
You should, therefore, make the following checks of flying accuracy:
•Check your heading. Is it the planned heading? Pilots have been known to select a figure group from the wrong column of their flight log when setting course from a turning point, or to steer the true track, instead of the magnetic track, or even to take the groundspeed figures as their heading to fly. You should, therefore, consider highlighting with marker pen or coloured pencils the correct magnetic heading, or even better, compass heading, on your Flight Plan. (See Figure 14.1.)
If you realise that you are lost, do not
fly around aimlessly. Carry out the lost procedure.
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Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
Customer: Oleg Ostapenko E-mail: ostapenko2002@yahoo.com
CHAPTER 14: THE LOST PROCEDURE
Check the synchronisation of your DI with the magnetic compass, when you are flying in straight, steady, unaccelerated flight.
•Check the synchronisation of the Direction Indicator (DI) with the magnetic compass and ensure that no metal objects (such as bulldog clips, cameras or torches) are stowed adjacent to the compass where they could affect the heading indication. If your compass is giving erroneous indications, you will not be able to synchronise your DI correctly.
•Check that variation, deviation and wind correction angle have been applied in the correct sense in your flight planning calculations, and entered correctly in your flight log.
•Check that the airspeed is as planned.
•Check your stopwatch or clock. It may have stopped. Timing is very important in navigation. If your watch has stopped, you will have lost the most important reference for knowing when to look for planned checkpoints and fixes.
Figure 14.1 Make sure that you are steering the correct Magnetic Heading, or even better Compass Heading..
If you discover an error in any of the above parameters early enough, you should be able to estimate your position using the mental dead reckoning methods that you have learnt in this book and estimate a heading and time required to regain your planned track, or to arrive at a planned destination or turning point.
Inaccurate Wind Forecast.
Even if your pre-flight navigation calculations were good, and though you have been flying accurate, planned headings and airspeeds, you may still be off-track and uncertain of position if the forecast wind direction and speed were significantly different from the actual wind velocity. However, if you have chosen good visual check points at appropriate intervals along track, and marked them on your chart, you should be able to identify any drift from your planned track well before you become uncertain of your position. Once drift has been recognised, your planned track may be regained and a new heading chosen, using the methods taught in Chapter 13 on Practical Navigation.
THE LOST PROCEDURE.
The advice that follows is just that: advice. There are several ways of attempting to re-establish your position, if you are unsure of where you are. The method we suggest in the following paragraphs is not the only valid method but it is logical and effective.
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