ADS and TCAS 'Unreliable" For Entire Month of September Out to 200nm Off US East Coast

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ArmyATC
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Wed Sep 02, 2015 2:51 pm

ADS and TCAS 'Unreliable" For Entire Month of September Out to 200nm Off US East Coast
ADS-B surveillance and some TCAS operations in the airspace over Virginia, North and South Carolina, Georgia and Florida might become unreliable as of September 2 at 1 a.m. EDT, according to a Notam the FAA issued on September 1. The outages are due to events the agency labeled as “late notice from the Department of Defense of military exercises.” NBAA “voiced its concern to the FAA that these sort of significant impact tests need much more notice to operators in the National Airspace System.”

The outages are scheduled to last until midnight October 1. In addition to the areas of concern noted in domestic airspace, the FAA said the outages might well extend up to 200-nm offshore.
AND
Dear ForeFlight Customer,

We want to make you aware of the following late breaking NOTAMs that have been issued due to military activities that may affect ADS-B traffic service over Virginia, North Carolina, South Carolina, Georgia, and Florida beginning 1:00 am EDT September 2, 2015 until midnight EDT October 1, 2015.

The NOTAM numbers are as follows:

5/2817 New York Center (ZNY)
5/2818 Washington Center (ZDC)
5/2819 Jacksonville Center (ZJX)
5/2820 Miami Center (ZMA)
5/2834 NY Oceanic (ZWY)

For reference, here is the text from the ZNY NOTAM:

A0369/15 (FDC 5/2817) - SPECIAL NOTICE...DUE TO MILITARY ACTIVITIES ON 1030/1090 MHZ, THE TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS) AND AUTOMATIC DEPENDENT SYSTEM BROADCAST (ADS- SURVEILLANCE MAY BE UNRELIABLE IN THE AIRSPACE OVER THE STATES OF VIRGINIA, NORTH CAROLINA, SOUTH CAROLINA, GEORGIA, AND FLORIDA, AND EXTENDING APPROXIMATELY 200NM OFFSHORE. PILOTS ARE ADVISED THAT THE TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS) MAY FAIL TO ESTABLISH TRACKS ON NEARBY AIRCRAFT AND MAY FAIL TO RECEIVE TRAFFIC ALERTS (TA) AND/OR RESOLUTION ADVISORIES (RA). FURTHER, PILOTS ARE ADVISED THAT TRACKS MAY FIRST APPEAR WITHIN CLOSE PROXIMITY TO THEIR AIRCRAFT AND MAY IMMEDIATELY GO INTO TA/RA STATUS. FALSE ALERTS ARE NOT EXPECTED TO BE GENERATED BY THIS MILITARY ACTIVITY AND ANY ALERTS SHALL BE TREATED AS REAL

Well this is just peachy. Our military is interfering with flight safety, detection/surveleince up to 200nm off the East Coast? WTF???

September has just got even more interesting.



http://www.ainonline.com/aviation-news/ ... -september
http://www.pilotsofamerica.com/forum/sh ... ?p=1877343
Last edited by ArmyATC on Wed Sep 02, 2015 4:03 pm, edited 2 times in total.
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ArmyATC
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Wed Sep 02, 2015 3:42 pm

Tanith wrote:Neither of those links appear to be working, AA.

Not sure I understand all this...are they saying it's unsafe for airliners, smaller private planes, or everybody? I don't speak Aviation.

:shock:
Although a traffic alert and collision avoidance system (TCAS II) is not an integral component in the ADS-B systems on-board aircraft, the two systems are closely linked. Created to reduce the possibility of mid-air collisions, TCAS involves communication among all aircraft equipped with an appropriate transponder.

TCAS version 7.1 also makes four other minor enhancements to the system:

Corrects an issue when an aircraft is descending through 1,000-feet above ground level (AGL)

Modifies the Datalink Capability Report (the TCAS status report sent by the TCAS processor to the Mode S transponder) to tell the systems that the TCAS processor is Hybrid Surveillance- capable.

Allows for the transmission of the TCAS processor part number and software level.

Corrects TCAS multi-aircraft logic issues that reduces the risk of close-encounters of multiple aircraft in RVSM airspace.

(ADS-B) This information is processed in real-time and sent to ATC and can be published online for flight-tracking purposes. Ground stations receive these signals and rebroadcast them for other aircraft to see, effectively merging the 1090 and 978 MHz systems. The rebroadcast traffic service is referred to as Traffic Information Services-Broadcast (TIS-B). Other aircraft can directly receive these signals if both aircraft are equipped to do so. ATC uses the aircraft-based information to tighten the lateral separation at altitude and tighten the lateral and vertical separation when the aircraft is ascending or descending through airspace.
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A long way of saying it gives ATC radar info and pilots on-board radar to avoid collisions. It also detects aircraft approaching our coast, even with transponders off (primary target).

It is for safety and early warning (although that's a secondary function). So for the DOD to mess with this is very unsafe, unwise, and potentially fatal. Remember all those false targets on 9-11. The NOTAM (Notice to Airmen) says it is not 'expected' to create false signals. Imagine an commercial airliner taking dangerous evasive maneuvers not knowing which way to turn to avoid collisions. On top of Russian bombers with transponders off..well you get the picture.

It's like saying, 'our East Coast will be unsafe and less survieled for the next month in case you want to stop by..'

It could be used offensively to disrupt foreign military on-board radar as well, create fake targets for the enemy (and the public), etc.. giving DOD the benefit of the doubt, but that would indicate they expect an attack or are willing to test a new toy needed very soon to go to this level of actually endangering the general public, imo..

Tanith, now try the links.. I think they are up. Thanks

The concerning part is the placement in the southern east coast. With only a 200nm reported range, that would do little to offensively disrupt RF flights from the north.
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Wed Sep 02, 2015 6:22 pm

Tanith wrote:Yes, they're working now, thank you.

I don't have any plans to fly in the next month (that I know of), but shared it to my FB feed just the same. It's unsettling.

To be "blind" in a communication sense for even a short period of time is unsettling. Sometimes when my internet goes out I freak out, but this is for an aircraft, with passengers!
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Wed Sep 02, 2015 6:32 pm

I have a 1090mHz receiver setup here and use plane plotter server software to plot local traffic. I also live 15 miles away from a Lockheed Martin plant that manufactures military helicopters. A few years ago there were a few NOTAM's stating that ADS and TCAS would be unavailable for 48 hours. During those 48 hours, there were probably 100 helicopters that left the plant heading south. Directly over my house. ADS-B was received by me like normal, but when I checked the commercial websites, there were no squaks listed within 200 miles of my house.
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Wed Sep 02, 2015 9:27 pm

Being aviation dumb here, these systems are there to warn individual pilots they or either too close to another aircraft or on a possible collision course with another aircraft, correct?

I guess the military is going to borrow the frequencies these systems work on, is that correct?

The big question, why?

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Wed Sep 02, 2015 11:29 pm

Ryan wrote:
Ill let AA answer that. Although I can he can be more descriptive.
Didn't know you were a pilot Ryan. We are gonna have to Teamspeak some aviation war stories some time for fun! :)

For BV, I'll keep it simple:

Here is a NOTAM, Notice to Airman, a procedure the FAA uses as an advisory service for aviation matters, weather, war zones, etc. Very good intel source BTW:
A0369/15 (FDC 5/2817) - SPECIAL NOTICE...DUE TO MILITARY ACTIVITIES ON 1030/1090 MHZ, THE TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS) AND AUTOMATIC DEPENDENT SYSTEM BROADCAST (ADS- SURVEILLANCE MAY BE UNRELIABLE IN THE AIRSPACE OVER THE STATES OF VIRGINIA, NORTH CAROLINA, SOUTH CAROLINA, GEORGIA, AND FLORIDA, AND EXTENDING APPROXIMATELY 200NM OFFSHORE. PILOTS ARE ADVISED THAT THE TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS) MAY FAIL TO ESTABLISH TRACKS ON NEARBY AIRCRAFT AND MAY FAIL TO RECEIVE TRAFFIC ALERTS (TA) AND/OR RESOLUTION ADVISORIES (RA). FURTHER, PILOTS ARE ADVISED THAT TRACKS MAY FIRST APPEAR WITHIN CLOSE PROXIMITY TO THEIR AIRCRAFT AND MAY IMMEDIATELY GO INTO TA/RA STATUS. FALSE ALERTS ARE NOT EXPECTED TO BE GENERATED BY THIS MILITARY ACTIVITY AND ANY ALERTS SHALL BE TREATED AS REAL
The two systems referred to are TCAS (Trafffic Collision Avoidance System) and ADS-B (Automatic Dependent Surveillance Broadcast-BTW there are ADS-C,CPDLC, ATC COM, ACARS, AOC which have related functions which seem to be not affected).


Image

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Starting with ADS-B, which is for ATC to coordinate with transponder equipped A/C, which virtually all aircraft have, and is mandatory for commercial airliners. This system is diagrammed above and is ground-based integrated with avionics on the planes.

The NOTAM says will be unreliable because it operates on the referenced frequencies. The ADS-B system can be configured for aircraft-to aircraft collision avoidance as well as providing secondary radar targets (virtual, not primary). That's why any manipulation of these freqs can not only make aircraft appear and dissappear for nefarious or offensive purposes, they can be hijacked to display wrong positions of two approaching aircraft and even have rogue voice transmissions.

Now for TCAS. Here is a visual:

Image

TAs are Traffic advisories
RAs are resolution advisories (the computer will interpret whatever input, real or imaginary and make an recommendation)

Image

To save time, I will copy Wikipedia to expalin:
the following points receive emphasis during pilot training:

Do not manoeuver in a direction opposite to that indicated by the RA because this may result in a collision.
Inform the controller of the RA as soon as permitted by flight crew workload after responding to the RA. There is no requirement to make this notification prior to initiating the RA response.
Be alert for the removal of RAs or the weakening of RAs so that deviations from a cleared altitude are minimized.
If possible, comply with the controller's clearance, e.g. turn to intercept an airway or localizer, at the same time as responding to an RA.
When the RA event is completed, promptly return to the previous ATC clearance or instruction or comply with a revised ATC clearance or instruction

Type Text Meaning Required action[1][2][5]
TA Traffic; traffic. Intruder near both horizontally and vertically. Attempt visual contact, and be prepared to manoeuvre if an RA occurs.
RA Climb; climb. Intruder will pass below Begin climbing at 1500–2000 ft/min
RA Descend. Descend. Intruder will pass above. Begin descending at 1500–2000 ft/min
RA Increase climb. Intruder will pass just below Climb at 2500 – 3000 ft/min.
RA Increase descent. Intruder will pass just above. Descend at 2500 – 3000 ft/min.
RA Reduce climb. Intruder is probably well below. Climb at a slower rate.
RA Reduce descent. Intruder is probably well above. Descend at a slower rate.
RA Climb; climb now. Intruder that was passing above, will now pass below. Change from a descent to a climb.
RA Descend; descend now. Intruder that was passing below, will now pass above. Change from a climb to a descent.
RA Maintain vertical speed; maintain. Intruder will be avoided if vertical rate is maintained. Maintain current vertical rate.
RA Level off, level off. Intruder considerably away, or weakening of initial RA. Begin to level off.
RA Monitor vertical speed. Intruder ahead in level flight, above or below. Remain in level flight.
RA Crossing. Passing through the intruder's level. Usually added to any other RA. Proceed according to the associated RA.
CC Clear of conflict. Intruder is no longer a threat. Return promptly to previous ATC clearance.
So any interference obviously affects aviation safety. If you plan on flying in the mentioned areas, well at least you know. My concern is for DOD to endanger aviation safety and announce it, this is serious. If it were some defense strategy against the RF, the positioning in the south east coast region and the reported range of only 200 nautical miles, means it will provide little or no protection from aircraft from the northern Atlantic.

So, while I understand training with new toys is required, a much smaller scale on a military range would be much safer. So this is truly unprecedented, and I have no idea why a decision was made to endanger thousands of flights with millions of people for an entire month in one of the busiest areas of the US. The risk of some sort must outweigh the safety somehow is all I can think.
"We have war when at least one of the parties to a conflict wants something more than it wants peace."

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Thu Sep 03, 2015 12:11 am

Just great.... JUST FLIPPEN GREAT.

I'm planning on going to Atlanta on the 13th of September...... woohoo flippen woohoo. Can't wait to be a victim of a aircraft collision.

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Thu Sep 03, 2015 12:34 am

matty1053 wrote:Just great.... JUST FLIPPEN GREAT.

I'm planning on going to Atlanta on the 13th of September...... woohoo flippen woohoo. Can't wait to be a victim of a aircraft collision.
Forgive me if I'm wrong, but I don't you're in that much danger. Atlanta isn't on the East Coast. It's about 248 miles away from the coastline. Unless you're flying from Europe or part of your flight path takes you over the ocean, you should be fine.
The release of atomic energy has not created a new problem. It has merely made more urgent the necessity of solving an existing one.
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Great, let's round up all the useless cats and hope a tree falls on them.
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Thu Sep 03, 2015 1:38 am

Oh thank god lol

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ArmyATC
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Thu Sep 03, 2015 10:54 am

matty1053 wrote:Oh thank god lol
Don't want to frieghten you, but the NOTAM specifies the entire airspace over Goergia will be affected. Don't freak out, just be aware and pray ;) if its clear weather, or your above the clouds) pilots usually will tell ATC and their inboard computers, 'traffic in sight', meaning they will be handling seperation themselves, no computer false targets or rogue voice commands will cause them to fly into another plane (which is kinda hard to do, even intentionally).

But if it's bad weather, on the climb out and decent ( if your destination is in one of those states), and the pilots are flying by instruments alone, well that's the worse case scenerio. And that would only be for a short time, not your entire flight.

It's just weird they would even endanger one person/flight over this, even if the chances are small. Very unprecedented.
"We have war when at least one of the parties to a conflict wants something more than it wants peace."

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