Tag Archives: Mode S

[Animation] The Queen's Diamond Jubilee flypast over London as seen from a radar-like computer display

Click on the image to start animation

The following animation showing the Queen’s Diamond Jubilee flypast over Buckingham palace was recorded on PlanePlotter by John Locker.

In this animation we can see the C-47 Dakota flight  [ZA947] and Lancaster flight [PA474] join up then fly down the Mall before breaking off to the north.

Other aircraft can be clearly seen in the animation: [CWL68] were the B200s with serial ZK453 and ZK454 (with SCE84 being probably a spare Beech); [P7350] was the Spitfire; [NOH23] was a chopper out of RAF Northolt, possibly on security duty.

Noteworthy, a Spitfire and a Hurricane pop up in the early frames but once joined up, only the lead aircraft in each section continued with Mode S.

Image courtesy John Locker

PlanePlotter (PP) is a software that receives and decodes live digital position reports from aircraft and plots them on a chart.

Using PlanePlotter, you can see a radar-like display of all those aircraft around you that are transmitting the appropriate digital messages including ACARS, ADS-B and HFDL. Needless to say, you need the appropriate hardware (receiver, antenna, etc.) to get the digital signals.

Unlike other very well known Internet services, as Flightradar24.com or Planefinder.net, PP has some more features, including

  • Multilateration to locate and track those aircraft which do not send  position reports
  • Beamfinder, Beamfinder Plus and Beamfinder Plus S: PlanePlotter can use the pings from known radar stations to calibrate the rotating beam and to use that information to locate aircraft not transmitting position

A330 MRTT (Multi-Role Tanker Transport) adds two new combat types: UAE Mirage 2000 and F-16 Block 60. And does it live on Flightradar24.com

Airbus Military has been very busy recently adding another two combat types able to be refueled from its A330 MRTT tanker aircraft, which has been ordered in three examples by the UAE Air Force.

The company, which is part of the EADS conglomerate, has performed several test flights out of Al Dhafra airbase near Abu Dhabi with the UAE AF F-16 Block 60 and the Mirage 2000 fighters. The tests, which included aerial refueling during climbs, descents, turns as well as straight and level flight were performed at a range of altitudes and speeds.

Even if the F-16 has already been qualified to be refueled from the A330 tanker this was the first time a Block 60 with the large conformal fuel tanks and a slightly different wake footprint than the older version of the F-16, has taken on fuel. Tests have involved aircraft in various loadouts.

The same tests were also performed on the Mirage 2000, including the two seat version with different loadouts as well as different fuel loads.

During the refueling tests of the Mirage the two underwing refuelling pods were used both to refuel a single jet and two jets at the same time. The F-16, that in the past were tested with a removable IFR (In-Flight Refueling) probe to take fuel from a hose-and-drogue tanker, used the Air Refuelling Boom System (ARBS).

For those interested in tracking some air-to-air refueling flights, please consider that they often appear on both Planefinder and Flightradar24 since the A330 MRTT broadcasts full ADS-B data from its Mode-S transponder.

For instance, using the radio callsign “CASA 013” the A330 EC-339 could tracked on Mar. 20, 2012 performing a refueling mission between FL240 and FL280. Click here to see the route followed by the MRTT during that sortie.

The track flown on Mar. 19, 21, 22 and 25 can be found as well using the playback feature of FR24.com.

Antonio Caramazana, Vice President Programme Director Airbus Military Derivatives, said: “It is very satisfying to qualify another two aircraft type as receivers for the A330 MRTT and we look forward to entry into service with the UAE Air Force later this year.”

The air crew training for the A330 with UAE pilots is currently taking place in Spain with the first two MRTT’s due to be delivered before the end of the year. The training of the aircrew takes place at Airbus’ training facility near Madrid and included not just the pilots but the refuelling operators too all using state of the art simulators.

Written with The Aviationist’s Editor David Cenciotti

Image by Richard Clements

Forget any security concern and welcome Air Force One on Flightradar24!

In my article titled Would modern transponders have made the hijacked planes visible to radars on 9-11? about Mode-S and ADS-B usage I wrote:

According to an esteem by Flightradar24.com, around 60% of the civil airliners and only a small amount of business jets and military aircraft have an ADS-B transponder. This means that, although you will never spot a Stealth Helicopter nor Air Force One broadcasting its position, speed, altitude and route on the Web, you can still catch some extremely interesting  planes. As the evasive US Air Force C-32Bs (a military version of the Boeing 757), operated by the Department of Homeland Security and US Foreign Emergency Support Team (FEST), used to deploy US teams and special forces in response to terrorist attacks.

I was wrong.

Although even the Flightradar24 FAQs confirmed that the Air Force One, the world’s most famous and important aircraft, should NOT be visible on their website, for a few seconds around 19.40UTC, the U.S. Air Force’s VC-25 (mil version of the B747), with registration 82-8000, transponder code 3614, advertised its position in the public domain while over Baltimore, descending through FL120 at 310 kts, heading towards Washington D.C. (for landing at Andrews AFB).

I don’t really know the reason for this quick appearance of the AF1 on FR24. A human error? A quick test? Hard to say. I’d expect the IFF Mode 5 with encrypted Mode-S and ADS-B to be paramount on the aircraft carrying the POTUS.

However, in the past I’ve witnessed some “doomsday planes” and other DoD flights shamelessly broadcasting on the Internet their position, altitude, track etc.

Let’s see what happens in the future. Maybe tracking Obama’s movements across the world will be possible. By means of a web browser….

Update Dec. 1, 2011: further investigation shows that the AF1 used genuine full ADS-B signal possibly triggered at the request of controllers for positioning purposes during descent to Andrews AFB.

The mysterious E-6B orbits over UK on the night Osama Bin Laden was killed

The first thing I did when Lee Armstrong told me to give a try to Planefinder‘s new search feature was to look for some E-6Bs, which are among the most interesting military planes to advertise their position on the Web using full ADS-B. They can be seen flying around the main operating base of Tinker AFB, or near the two alert bases on the West and East coasts (respectively, Travis AFB, California, and NAS Patuxent River, Maryland) under the bogus callsign “GOTO FMS”.

Since I found four of them overflying the U.S.  I ironically tweeted:

There are at least four E-6B doomsday planes over the US now. One of them on an intriguing route across Nevada (Tonopah range -> Las Vegas)

Many of my followers reacted to my tweet with questions and retweets. I explained them that the E-6B TACAMO (“TAke Charge And Move Out”) is not only used transmit instructions to the fleet ballistic missile submarines in case of nuclear war but that they are also used as back up of the four E-4Bs NAOC (National Alternate Operations Center), operating as ABNCP (Airborne Command Post) platforms.

Everybody know E-4Bs are extremely important. In the event of a war, a terrorist attack, an alien invasion and so on (hence the “doomsday plane” nickname), these aircraft are destined to keep the Secretary of Defense, the Joint Chiefs of Staff and other “decision makers” alive to direct nuclear (and conventional) forces, by receiving, verifying and relaying EAM (Emergency Action Messages).

One aircraft is usually airborne every 12 hours, with another one ready for departure with a 5-minute notice. If national command centers on the ground are attacked or unavailable, an E-4B is immediately scrambled: that’s why a “doomsday plane” was seen orbiting above Washington DC minutes after a hijacked plane had crashed into the Pentagon on 9/11.

The E-6B Mercury can do the same job. Built on the Boeing 707 airframe and using a B737 cockpit, this aircraft has a range of 5,500 miles, and accommodates 23 crew members. The U.S. Navy has a total fleet of sixteen E-6Bs. It can perform the so-called Looking Glass mission (mirroring the ground-based C3 center at Offutt AFB and relaying orders), it can talk to submarines trailing a 26,000 ft wire antenna, it can launch commands to ICBMs (InterContinental Ballistic Missiles) via Airborne Launch Control System, and can perform C3 (Command Control Communication) operations to forces operating in theatre. For this reason they are often deployed abroad: they were monitored in Iraq and have been deployed to the UK in the past.

An E-6Bs flying over the UK when Osama Bin Laden was killed

Even if I was sure that an E-6 had taken part to the raid at Abbottabad as an ABNCP platform (to such an extent that I had put one these planes in the “crime scene” of my Operation Neptune’s Spear explained article) I had never realized that the one over UK could be linked to the Osama Bin Laden raid. Actually, I wasn’t even sure that the plane deployed to RAF Mildenhall since Apr. 28 was flying when the raid took place.

However, once again I thought that Planefinder could be of some help. Its new playback feature gives you the opportunity to monitor the traffic from Apr. 1, 2011 onwards. I gave it a try and found that “Iron 18” (registration 164409 – “GOTO FMS” on the Mode-S transponder – a VQ-3 “Ironman” airframe based on its callsign), was flying at 310 Kts, FL260 one of its 8-hour round robin missions (made of some counter-clockwise laps) over the UK around 19.0o UTC on May 1, 2011, at the same time when the Stealth Black Hawk had landed at the Bin Laden’s compound.

Two screenshots showing Iron 18 orbiting over the UK on May 1, 2011 (the previous days’ tracks are not purged by Planefinder’s playback feature so also the inbound track from the US is still visible)

Interestingly, the same aircraft had flown the same mission profile on the previous days, landing more or less at the same time it did on May 1 (at 20.26 UTC), as if it had performed a couple of work up sorties at the same altitutes, speeds and times.

Actually, these kind of orbits over the UK have been flown from some years and communication relay missions take place nearer to the area of operations. However, the mysterious E-6B presence in the British skies while the most important US military operation of the recent time took place can not be a coincidence. The Mercury is capable to communicate on virtually every radio frequency band, on commercial satellites and on the Internet, using also a secure VOIP system.

What if it was orbiting over the UK to exploit a particular geostationary satellite or to act as a back up ABNCP  another E-6B flying in the vicinity of Abbottabad?

There’s also another intriguing hypothesis: “Iron 18” was performing command and control relay to two stealth B-2s that were flying somewhere in the vicinity of the Pakistani airspace, ready to bomb the compound in Abbottabad if the Navy Seals raid on board the Stealth Black Hawk failed to kill or capture Osama Bin Laden. In fact, we know for sure that, in March 2011, Obama authorized the U.S. to bomb Osama bin Laden’s compound using two B-2 bombers but changed his mind when he learned the compound would be wiped out and there would be no DNA proof of his death. But we can’t rule out the possibility that an air strike with 2,000 lbs GBU-31 GPS-guided bombs would be the “Plan B” if the Navy Seals raid failed.

E-6B 164409 in a picture taken by Andrew W. Sieber in 2007

Would modern transponders have made the hijacked planes visible to radars on 9-11?

As everybody know by now, on Sept. 11 2001, the first thing terrorists did as soon as they reached the cockpit of the four hijacked planes was turning the transponder off. This made the doomed planes almost invisible to the radars on northeast U.S. rendering the US Air Defense response to the attacks in New York and Washington DC extremely difficult.

In the aftermath of the celebrations for the 10th Anniversary of the 9-11 attacks, many visitors of this website asked me if the ADS-B transponders would have enhanced the capabilities of NEADS to identify and track the hijacked planes. This article answers that question.

[Read also: 9/11: a fighter pilot’s account]

What’s a transponder?

In aviation, a transponder is an electronic device carried by an airplane that operates as a radio receiver and transmitter. The transponder is the key component of the secondary surveillance radar (SSR) system. It produces a coded response upon radio-frequency interrogation: each plane is assigned a transponder code by the air traffic control agency, known as “squawk,” that is used to reply to interrogations with information such as the plane’s speed and altitude.

Data transmitted by the aircraft transponder is then displayed on the radar screen to assist the controller providing instructions and ensuring proper separations between flights.

When the aircraft turns its transponder off, it only passively bounces radio waves sent by the radar becoming a “non-cooperating” target in a primary surveillance radar (PSR) scenario: the pulse of radio energy sent out by the radar is reflected by the surface of the target plane back to the receiver providing the bearing of the aircraft from the ground station and its distance (calculated as the time taken by the pulse to reach the target surface and return).

Since only a fraction of the interrogation pulse is reflected back to the ground radar, the reply signal has a reduced range and is subject to signal attenuation. Hence, it can be difficult to detect.

For this reason on 9-11, after losing the transponder replies, FAA controllers were unable to determine with accuracy the actual position of the hijacked planes and transfer the information to the interceptors of the US Air Force.

Image source: ENAV


Next Generation airspace is based on another kind of system that not only improves radar accuracy and traffic avoidance for better safety, but also provides million users only “equipped” with an Internet connection, a web browser and a computer, the opportunity to follow the live air traffic all around the world as they were real ATC controllers.

The famous Flightradar24.com or PlaneFinder.net, both available also as iOS and Android apps, exploit the ADS-B (Automatic Dependent Surveillance – Broadcast). The ADS-B system uses a special transponder that autonomously broadcasts data from the aircraft’s on-board navigation systems about its GPS-calculated position, altitude and flight path. This information can be received by ground stations, by other nearby aircraft (thus enhancing situational awareness) and also by commercial off-the-shelf receivers available on the market as well as home-built ones.

Flightradar24 and PlaneFinder have a network of several hundred feeders around the world who make the flight information received by their home kits available for anybody. Obviously, only ADS-B equipped aircraft flying within the coverage area of the network are visible.

According to an esteem by Flightradar24.com, around 60% of the civil airliners and only a small amount of business jets and military aircraft have an ADS-B transponder. This means that, although you will probably never spot a Stealth Helicopter nor Air Force One broadcasting its position, speed, altitude and route on the Web, you can still catch some extremely interesting planes. As the evasive US Air Force C-32Bs (a military version of the Boeing 757), operated by the Department of Homeland Security and US Foreign Emergency Support Team (FEST), used to deploy US teams and special forces in response to terrorist attacks.

What if the ADS-B was used on 9-11?

Since ADS-B system uses onboard transponders, its use on 9-11 would not have improved the detection capabilities of the radars. ATC control centers would have remained as blind as they were during the attacks.

The only difference is that millions users would have been able to track the hijacked planes until their transponder were turned off and, minutes later, they would have seen all civil planes flying across the country diverting to the nearest airports while the US airspace was being shut down.

Top Image credit: Wiki