Originally published at: NTSB Warns Congress Over DCA Airspace Provision
Letter from NTSB agency chair cites concerns tied to January midair collision.
After GPS was released for public use by Pres. Reagan, ADS-B was envisioned as an inexpensive air-to-air replacement for TCAS, which is limited to last-minute vertical escape maneuvers. Even after successful IFR use in Alaska under Capstone and the successful OpEval-2 in 2000, the next OpEval-3 was cancelled and the system was shelved. Position reporting to ATC by ADS-B OUT was so dramatically improved over radar that it was mandated by FAA. DOT and Congress now have a great opportunity to re-energize ADS-B IN and mandate the system for all, which makes it affordable by all. Controllers can relax with a backup role and concentrate on traffic management. Extending this to all aircraft might require more controllers, but the stress would be much less.
Reminds me of the LAX crash in 1991 when a USAir 737 landed and collided with a SkyWest Metroliner holding in position at an intersection. Quickly, new rules were handed down that prohibited position and hold at night at an intersection, nationwide. However, a waiver was issued because the new rule severely hampered the operations at a major airport. Who received the waiver? LAX!!
Having ADS-B in mandated would not have prevented the DCA collision. ADS-B in is advisory only, still relies on pilots having visual contact before making maneuvers to avoid traffic. The only way to prevent further issues with military helicopter traffic and airliner traffic in DCA would be to ban one or both. DCA needs to be closed, the secret service has wanted it closed for years. Congress is not about to put any restrictions on DCA traffic that would inhibit their use of DCA for themselves. Can you imagine the outcry if a general aviation aircraft would have been involved in this accident?
I agree with you 100%, based on the current treatment of ADS-B IN by FAA. The only purpose of FAA ATC is to advise the pilot what he needs to do to prevent a collision. Full processing of ADS-B IN data would provide the same directly to the pilot, and to a far greater degree of reliability and lower false alarm rate than either ATC or TCAS. In fact, given GPS and ADS-B inputs, I am reasonably certain an app could be written for a smartphone. Who knows what AI would bring to the game? P.S In case you hadn’t noticed, it’s all neanderthal FAA/Industry/Union politics.
All lawmakers (political, administrative, civil service, whatever) and air traffic controllers who intend to opine on this should spend an hour or three in the right front seat of a piston single at night. Shoot some approaches, enter Class B airspace, see what it’s like. That will inform their thinking.
Are they up to the challenge of situational awareness? Do they understand that the system MUST depend on the people in the left front seat to get it all right all the time?
Plus, they should read what top conspicuity experts have to say about human inability to “paint” in the brain a correct picture from a few dots of light out the glareshield.
Understand the human factors problem you are dealing with, rather than just lashing out at symptoms!
The DCA accident was a mix of colossal policy and operational screw ups. Even if the Helo had been squawking ADS-B out, it wouldn’t have prevented the accident. The policy of allowing conflicting low altitude Helo traffic to cross short final within 150’ vertical feet of an airplane on final is something the FAA flight standards and air traffic safety arm would never sign off on without being directed to do so from someone or a group of people in a very high political positions. I have yet to see anyone to be held accountable or even identified as responsible for this policy debacle.
Operationally, it’s clear the that the Helo PIC screwed up. I would argue the controller also screwed up by even allowing the Helo to proceed beyond Haines Point until the CRJ was beyond the point of conflict… should have been handled like an airport surface operation.
ADS-B specifications were developed to support self-separation, but stopped short of including conflict and collision avoidance applications specifications to support it. TCAS algorithms could easily be adapted to do so, but there have been too many political obstacles, namely controller and pilots unions and airlines not wanting the liability. ADS-B messages would also need to include intent information (beyond the just the state vector) to minimize false alerts, e.g. current nav waypoint and next waypoint with a new course. Regardless, the controllers would still need to be the primary separation authority on and around airports with conflict and collision avoidance as backups.
Finally, a secondary form of RNAV would be needed to mitigate GPS interference, e.g. dme/dme, pseudo-lites, eLORAN. All of that, plus automated datalink hand-offs and clearances would represent “Modernization of the ATC system”, not the BS Duffy is being sold about updating the radars. Radar updates are certainly needed to make a transition to a modernized system that would take well more than 3 years to complete, but updating the radar system is not modernization of the ATC system.
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