The comfort of knowing your Aircraft Situation Display to Industry (ASDI) information is “blocked” or unable to be tracked on websites is becoming more of a discomfort for some operators thanks to something called Automatic Dependent Surveillance-Broadcast – or ADS-B.

A few years ago, all it took to have your tail number blocked was a simple request to the National Business Aviation Association (NBAA). Then once a month, the requested batch of tail numbers would be entered into the Federal Aviation Administration (FAA) live data feed, and depending on the level of blocking desired, the tail number would be blocked in that manner. It was, and still is a very simple and painless process, with one exception.

There are two choices to make when registering for the program. One choice, in theory, blocks the FAA live data at the internet provider level. This means the internet providers (i.e., the flight tracking websites) are responsible for blocking the tail numbers on the list received each month. Failure to adhere to blocking these tail numbers could result in the FAA terminating their live feed of air traffic data to the website. It is a compelling reason for the websites to respect the blocked tail number list should they desire to continue to receive their main source of air traffic data.

There are some benefits to being blocked at the internet level. For a fee, your flight department can track the aircraft and smart FBOs can track your arrival into their facility. On the downside, although your tail number does not show, if you are flying, for example from Teterboro to London Stansted and have filed your flight plan, a flight plan for your aircraft type from Teterboro to London Stansted will show on all of the public flight tracking websites.

The other choice is to block the tail number at the FAA level. This is the most secure choice. The FAA does not send any live data from your aircraft to the internet providers; the data is only within the FAA towers and system. Internet providers are unable to access FAA data when flight plans and call signs are filed under your double-blocked tail number.

The benefit of being blocked at the FAA level is privacy if the flight plan and call sign are the tail number of the aircraft. The FAA does not send data out on your tail number. FBOs should not be able to track your arrival, and individuals should not be able to see the aircraft through the internet with FAA data.

But that is all changing now. There really is not much privacy any longer. If an aircraft is blocked at any of the two levels and uses a call sign, the aircraft is fully trackable by that call sign. Now with ADS-B, any aircraft can be tracked at any time in almost every corner of the world.

ADS-B is the latest big thing in the FAA’s NextGen air traffic modernization program, and the FAA will require that all aircraft operating in airspace that require a Mode C transponder be equipped with ADS-B by 2020. However, ADS-B will not overturn the transponder requirement.

With the mandated requirements of ADS-B looming on the horizon, more and more aircraft around the world have become equipped for ADB-S Out capability. This broadcasts specific encrypted data on position, airspeed, and altitude based on GPS that can be picked up on certain frequencies by ground stations and other aircraft nearby.

ADS-B In, which is not included in the FAA mandate, also requires additional equipment and allows aircraft to receive data from ADS-B ground stations and other aircraft in the vicinity, which are broadcasting their position with ADS-B Out.

Thousands of aviation enthusiasts excited about the ADS-B tracking technology have installed ADS-B receiver antennas on their rooftops around the world and are bringing all that data together for some popular flight tracking websites.

What does this mean for a flight department thinking their plane is blocked? It means that the ADS-B technology prevents aircraft from being fully blocked on some websites although a bit of knowledge is required to track and gain access to this free information.

Regardless, FAA data is still blocked as previously arranged – that has not changed. But ADS-B data from private citizens pooling the figures and pushing the information to flight tracking websites makes it easier to view what were once blocked aircraft, anywhere in the world.