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Transatlantic Drone Flight


David Smith reports on a long-range drone flight, a satellite-based virtual radar development


David Smith reports on a long-range drone flight, a satellite-based virtual radar development, and other Airband listening opportunities He then offers an ATC profile of Bristol Airport.


The MQ-9B SkyGuardian Remotely Piloted Aircraft System (RPAS) which landed at Fairford on 11 July for the airshow, had carried out a proving flight from Grand Forks Air Force Base, North Dakota.

A number of Temporary Danger Areas (TDAs) were established to facilitate its safe transit within the London Flight Information Region, routing via Strumble VOR direct to Fairford. In the event of it being unable to complete the flight to Fairford for any reason, the contingency plan was a diversion to either Culdrose or Predannack in Cornwall or to Llanbedr in North Wales. TDAs would have been established at the chosen destinations.


Satellite-Based ADS-B for RadarBox

AirNav Systems, the makers of the RadarBox real-time virtual radar receiver, has announced that their satellite-based ADS-B reception network will be available early in 2019 and will provide worldwide coverage.

For readers unfamiliar with the concept, by decoding Mode S and ADS-B (Automatic Dependent Surveillance-Broadcast) radar signals, you can see on your computer what air traffic controllers see on their screens in real time; flight number, aircraft type, altitude, heading and speed are all updated every second.

The company states: "Traditionally, ground-based ADS-B receivers, along with radar, have been used to track aircraft. This method, however, has had its own set of challenges, since ADS-B is based on the line-of-sight principle. Mountains, buildings, vast water bodies and other obstructions can significantly decrease a receiver's range and its ability to receive transponder-emitted signals.

“This limits a receiver's coverage to a small geographic pocket 150nm on average. Satellite-based ADS-B, we believe, is 'the next big thing' in the flight tracking domain as it enables us to provide flight data in places where ground-based ADS-B simply cannot reach."

AirNav systems explains further how this works: "Space-based ADS-B uses data from receivers that are placed on Nano-satellite constellations in space to track aircraft as they fly. With space-based ADS-B, we’ll be able to track aircraft anywhere on earth, even over oceans, thus allowing 100 per cent global air traffic surveillance, regardless of terrain, location or infrastructure. Tracking is not affected by weather or other natural phenomena. For a long time, we’ve wanted to guarantee worldwide nonstop flight tracking without interruptions or delays and now we can.

"By complementing the existing, ground-based, ADS-B network, space-based ADS-B will be able to provide a more complete picture to the users on the ground. Moreover, aircraft are not required to have any special equipment on board their aircraft or fleet, other than an ADS-B out transponder."

AirNav also says that those customers operating an aircraft or fleet and wishing to be compliant with mandatory international flight tracking requirements, can do so now using the space-based ADS-B constellation network and tracking their fleets under Business accounts.


South Midlands Airband Monitoring

Reader Christopher Lally, who lives in the Oxford area, has sent me a list of over 140 active airband frequencies found from home using just a handheld scanner with no external aerials. He writes: "For the VHF airband, I used the search facility until I had logged 100 active frequencies. For the UHF airband, I programmed my scanner with the London ATCC frequencies and all the frequencies from military airfields within a 100-mile radius.

"I would highly recommend the website as it not only gives you the airfield frequencies but also free map-pdfs of all the military airfields. In terms of changes noticed in airband scanning, the company operations frequencies, generally between 129 and 132MHz, are a lot quieter than they used to be. I presume airlines are now using email etc. However, overall, the VHF airband is still very busy.

"On the UHF airband, Benson, Middle Wallop, and Boscombe Down appear to be the busiest airfields. Northolt was only heard once and Lakenheath was very busy for only one day with air-to-air comms."


The box below shows my ATC profile for this month, for Bristol Airport.

My aircraft photo of the month is an EasyJet Airbus A319 at Liverpool.






Frequencies                          (MHz)                                       Hours of Operation


Bristol Approach/Radar            125.650                                     H24

Bristol Director                        136.075                                     H24

Bristol Tower                          133.850                                     H24         

Bristol Delivery                       121.925                                     As directed by ATC


(Bristol Delivery frequency 121.925 MHz may be open during peak daytime hours. 121.925 MHz is not monitored, if not operational.)



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Bristol Information                   126.025                                     H24 (available by telephone: 01275-475-686)

Bristol Fire                             121.600 (non-ATC)                      Fire vehicles when attending aircraft


Navaids                                ILS Cat III on Runway 27 Cat II on Runway 09

                                            NDB BRI 414.00kHz


Runways                               09                                             2011m x 45m 

                                            27                                             2011m x 45m


Holds                                   A one-minute racetrack procedure, approaching NDB BRI on track 095° turning left at the facility


Notes (A-Z)


Frequency Monitoring Code (FMC)

Pilots operating in the vicinity of (but intending to remain outside) Bristol controlled airspace, should maintain a listening watch only on Bristol Radar frequency (125.650MHz) and are encouraged to select SSR code 5077. Aircraft displaying the code are not expected to contact ATC under normal circumstances and should remain clear of controlled airspace at all times. When squawking 5077, pilots should be aware that Bristol Radar may make blind transmissions, in order to ascertain a particular aircraft's intentions/route. When a pilot ceases to maintain a listening watch, code 5077 should be deselected.


Handling Agencies

Mandatory handling for all aircraft: Bristol and Wessex Aeroplane Club (for aircraft up to 2.73 tonnes only); Centreline (Frequency: 130.625MHz); Menzies Aviation; Swissport.


Helicopter Operations

Helicopters must arrive/depart using the runway in use. Easterly departures are to turn north and follow the A38 after crossing threshold. Westerly departures should not turn north until crossing the aerodrome boundary. Westerly arrivals from the north should approach following the A38 road and join on a right-base for Runway 27, avoiding Felton village and the noise-sensitive area to the north. Helicopter circuit height is 700ft QFE.


Light Aircraft Operations

Runway 27: Circuit direction is normally left-hand.

Runway 09: Circuit direction is normally right-hand only.

ATC may require non-standard circuit direction for traffic integration.


Procedures for Inbound Aircraft

Standard Arrival Routes for aircraft inbound from the UK ATS Route network.

VFR and Special VFR aircraft will usually be instructed to route via one of the Visual Reference Points, not above an altitude of 2000 ft.


Procedures for Outbound Aircraft

Aircraft travel outbound via the ATS Route Network. Standard Instrument Departures for aircraft outbound are also via the UK ATS Route network. Instrument Flight Rules (IFR) aircraft wishing to leave the Bristol CTR/CTA to enter the London Flight Information Region (FIR), will be cleared by the most direct route consistent with the current traffic situation. VFR and Special VFR aircraft will usually be instructed to route via one of the Visual Reference Points, not above 2000 ft (aerodrome QNH).


Visual Reference Points (VRP)

There are no less than 19 of these. including Bath Racecourse, Cheddar Reservoir, Clifton Suspension Bridge, Devizes, M5 Sedgemoor Services, Old Severn Bridge, and Wells Mast.


This article was featured in the September 2018 issue of Radio User

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