Practice Pan calls are important to both pilots and the Distress & Diversion cell, for training and staying sharp… Part 3 of a series
WORDS: Flt Lt Jason Bowditch, Air Traffic Controller
25 March 2022
Welcome back! In this month’s edition we’ll be discussing practices, which is thankfully what we spend most of our time doing, although many would argue that we spend most of our time waiting for something to happen… (I jest).
Practices involve both Practice Pans and Training Fixes (simulated lost), which is brilliant for both our currency in Distress & Diversion and for you to practice your own procedures and gain increased trust in the system.
If you read the introduction article (Flyer, March, p46/47) you may recall us mentioning Auto-Triangulation (Auto-T), which covers large parts of the UK in varying degrees. The screens for Auto-T are directly in front of the D&D Controller and the Support Controller. It is this system that is predominantly used in anger during emergencies and for the multiple practices we receive each day. It’s still free to practice!
The solution for Auto-T is provided by Leonardo. There are various antennas around the UK which will lock-on to the aircraft transmitting if within suitable coverage. High ground or low flying aircraft are more difficult for the antennas to pick up. Throughout the country there are 30 UHF, 31 VHF and 12 Practice Emergency Training Frequency (PETF – Military only) antennas. The map shows you the locations of the current DF sites. (refers to image 1 below)
Auto-T is an incredible system. Not only does it lock-on to the aircraft calling up on the respective frequencies, but it overlays it onto an Ordnance Survey map which can be zoomed into a 100m range. This enables us to give accurate descriptions of the ground to help lost pilots find their bearings while looking out their windows. This could be anything from a motorway junction to a church spire.
As well as helping identify the location of aircraft on Guard, Auto-T couples as a huge database, which is carefully maintained. This has details of 143 civil aerodromes as well as 34 military bases.
The airfields on the database range from the major airfields to the farm strips dotted around the UK. The aerodromes and airfields are plotted on the Auto-T map and are all interactive. D&D can click on an aerodrome of interest and it’ll give us the runway, the Landing Distances Available (LDA), surface of the runway (be it asphalt or grass), frequencies (if applicable) and their phone number.
This enables D&D to pass timely and accurate information to the pilot and a steer to the nearest suitable aerodrome based on the aircraft’s needs and specification. Needless to say, this could be critical to pilots in need of making a quick decision.
If in any doubt, the earlier the call to D&D the better!
Now that we’ve discussed the system, this is where you come in.
GPPAN: ‘London Centre. Practice Pan, Practice Pan, Practice Pan, GPPAN, Practice Pan.’
D&D: ‘GPPAN, London Centre, Practice Pan acknowledged, pass details when ready.’
What cannot be illustrated is that during the initial call, the Controller and/or Support Controller will be jotting down your callsign and details, seeing which frequency you’re on, which frequency leg you’re transmitting on, how many lines of DF there are and plotting your initial position. It does take a little practice (hence the Practice Pans and Training Fixes are brilliant for us too).
The radio call continues:
GPPAN: ‘London Centre, GPPAN is a C152 with 2 POB, simulated stuck throttle, request steer for Fenland, G-AN’
D&D: ‘G-AN, London Centre Roger. Stand-by to steer.’
Here we’ll be ranging in and getting a range and bearing to Fenland.
Upon ranging in, the map becomes accurate in identifying local towns, villages, motorway junctions or even prominent hills.
D&D: ‘G-AN, your position indicates 1.5NM South of Grantham. Taking your own terrain clearance steer for Fenland is 110 degrees 23.5nm.’
G-AN: ‘Roger, 110 degrees, 23.5nm. G-AN’
D&D: ‘G-AN do you require any further assistance?’
G-AN: ‘Negative, G-AN’
D&D: ‘GPPAN roger, thanks for the call, continue on-route g’day!’*
*Straight from the CAP413.
With varying details, this is 90% of the Practice Pan calls we receive. Training Fixes are almost identical, but ‘Training Fix’ instead of ‘Practice Pan’ to simulate unsure of position or lost.
If there are only two lines of DF, we’ll caveat the accuracy with ‘based on two lines of DF which may be inaccurate.’ If none or only one line is observed, we’ll ask you to transmit a squawk and transpose your position from radar onto Auto-T.
If you’re squawking and we are still unable to observe you, we may ask you to climb (if it’s safe to do so), or request your last known position and call a nearby radar unit to see if you are visible on their radar and transpose your position based on their range and bearing information.
If all else fails we can see which leg you’re transmitting on, ask you for your last known position and get you to ‘say what you see’ out of the window… things on the ground, that is, not types of cloud. Make sure you stay vigilant of other aircraft – this is still your primary responsibility. This level of difficulty locating aircraft thankfully very rarely happens, but we’ll be doing all we can to locate you.
So there we have it. All trade secrets out in the open. Pre-Covid traffic levels, D&D would usually get on average 3,500 practices a year. We have had little over 3,500 in total over the last two years. Don’t be a stranger. After all… Practice Pans make perfect!