I did a search about anti-collision systems and then this "advertisement" displayed on my FB feed:

The Traffic Collision Avoidance System (TCAS) is an avionics system designed to reduce the risk of mid-air collisions between aircraft. TCAS operates independently of ground-based air traffic control and provides real-time advisories to flight crews to facilitate timely evasive action.

The primary functions of TCAS are:

1. Traffic Surveillance: TCAS continuously monitors the airspace around an aircraft, identifying and tracking nearby aircraft equipped with transponders within a designated range.
2. Resolution Advisories (RAs): If TCAS detects a potential collision risk, it issues advisories to flight crews, recommending vertical maneuvers to avoid conflicting traffic. These advisories are categorized as "Climb," "Descend," or "Clear of Conflict."

Mode S Transponders: TCAS relies on Mode S transponder technology. Aircraft equipped with transponders respond to TCAS inquiries with precise identification and altitude information. This two-way communication enhances the accuracy of traffic surveillance and advisory generation.

TCAS operates in two main modes:

TCAS I: Primarily used in general aviation, TCAS I provides advisory information to flight crews but does not coordinate resolution advisories with other equipped aircraft.
?TCAS II: Common in commercial aviation, TCAS II not only issues advisories but also coordinates resolution advisories between nearby TCAS-equipped aircraft, improving collision avoidance capabilities.
?Traffic Alert (TA) and Resolution Advisory (RA):-TCAS generates Traffic Alerts (TAs) and Resolution Advisories (RAs) based on the relative positions and altitudes of nearby aircraft:
?Traffic Alert (TA): A TA is issued when TCAS identifies a potential collision threat. It provides advisory information to flight crews, prompting increased situational awareness.
?Resolution Advisory (RA): If the system calculates a higher risk of collision, it issues an RA with specific instructions to climb or descend.

10 minutes ago, theguru said:

I hear you but I would also think the instruments/anti-collision systems would have given each pilot multiple warnings.  

The TCAS system does not give audible warnings below a certain altitude to avoid confusion when landing. 

7 minutes ago, TheDeuce said:

The TCAS system does not give audible warnings below a certain altitude to avoid confusion when landing. 

I thought I heard someone say that particular helicopter does not have a TCAS system.

Now the news is reporting the staffing was "not normal" in the air traffic control tower at the time of the collision. 

According to NBC News, there should have been one air traffic controller specifically handling helicopter traffic in the area at the time of the crash.

However, one controller was handling both helicopter and airplane activity in the area.

Just now, theguru said:

Now the news is reporting the staffing was "not normal" in the air traffic control tower at the time of the collision. 

According to NBC News, there should have been one air traffic controller specifically handling helicopter traffic in the area at the time of the crash.

However, one controller was handling both helicopter and airplane activity in the area.

If this is true, I would be looking hard at the air traffic controllers.  With that said, I know air disasters are investigated upside down, inside out, and then some more. 

1 hour ago, theguru said:

If this is true, I would be looking hard at the air traffic controllers.  With that said, I know air disasters are investigated upside down, inside out, and then some more. 

In the NTSB briefing, it seems that they have a solid plan of investigation. Their home lab is just one mile from the crash site.

I saw one guy speculate that from what he saw the helicopter flight profile and track was irregular before the crash and that the helicopter dropped around 200ft in altitude just moments before the collision.  His speculation was that there is a slim chance, but a chance that the helicopter could have intentionally flown into the path.

4 minutes ago, Jumper_Dad said:

I saw one guy speculate that from what he saw the helicopter flight profile and track was irregular before the crash and that the helicopter dropped around 200ft in altitude just moments before the collision.  His speculation was that there is a slim chance, but a chance that the helicopter could have intentionally flown into the path.

Seeing the video, it’s impossible for me not to think this is a possibility. 

5 minutes ago, Jumper_Dad said:

I saw one guy speculate that from what he saw the helicopter flight profile and track was irregular before the crash and that the helicopter dropped around 200ft in altitude just moments before the collision.  His speculation was that there is a slim chance, but a chance that the helicopter could have intentionally flown into the path.

Just now, TheDeuce said:

Seeing the video, it’s impossible for me not to think this is a possibility. 

I am horrified to think that is a possibility. 

13 minutes ago, theguru said:

I am horrified to think that is a possibility. 

Agreed.

16 hours ago, TheDeuce said:

Someone asked on TV if it were possible the helicopter was looking at the wrong plane and that's what caused the collision.

I can't see any way that would be possible. 

I'd heard or read somewhere there was also a CRJ on the runway.

So BH pilot was looking left, when he/she should have been looking right.

Also a possibility of BH crew wearing night vision goggles, and heard they distort depth perception.  I'd think with where we are in technology this wouldn't be an issue, but I have no true idea as I've never worn them.

18 hours ago, TheDeuce said:

The TCAS system does not give audible warnings below a certain altitude to avoid confusion when landing. 

1000 feet & below.

17 hours ago, TheDeuce said:

There's audio. The helo acknowledged the plane and was supposed to divert around it. 

Yeah, I've seen that now.  Still a lot of unknowns and speculation at this point.  

Here is a headline from foxnews.com:

Two planes aborted landings at DCA due to helicopters in flight path in week before crash: report

Military helicopter flights forced at least two planes to abort landings at (DCA) in the week before a deadly collision presumably killed 67 people on Wednesday, according to a report.

On Tuesday night, just one day before the collision between an American Airlines flight and an Army Black Hawk helicopter, a different plane alerted the air traffic control tower that it had to abort its landing to avoid collision with a helicopter, the Washington Post reported.

Yet another plane arriving at DCA from Charlotte scrubbed its landing on Jan. 23, again because of a helicopter.

https://www.foxnews.com/us/two-planes-aborted-landings-dca-due-helicopters-flight-path-week-before-crash-report

In other words, this is an ongoing issue and finally the unthinkable happened. 

It is hard to believe we have this level of incompetence at the FAA.

5 hours ago, theguru said:

Here is a headline from foxnews.com:

Two planes aborted landings at DCA due to helicopters in flight path in week before crash: report

Military helicopter flights forced at least two planes to abort landings at (DCA) in the week before a deadly collision presumably killed 67 people on Wednesday, according to a report.

On Tuesday night, just one day before the collision between an American Airlines flight and an Army Black Hawk helicopter, a different plane alerted the air traffic control tower that it had to abort its landing to avoid collision with a helicopter, the Washington Post reported.

Yet another plane arriving at DCA from Charlotte scrubbed its landing on Jan. 23, again because of a helicopter.

https://www.foxnews.com/us/two-planes-aborted-landings-dca-due-helicopters-flight-path-week-before-crash-report

In other words, this is an ongoing issue and finally the unthinkable happened. 

It is hard to believe we have this level of incompetence at the FAA.

I was talking to someone earlier that lived in DC for years and flew out of DCA and Dulles multiple times.  She said the airport was never designed for the amount of traffic that it has today.  Over the years, it has added so many direct flights to accommodate everyone so they don't have layovers like the common person.  For the past handful of years, she said she will only use Dulles, because she said this really was only a matter of time with the amount of air traffic around there.  

 

I looked at the comparisons between DCA and CVG just out of curiosity.  CVG sits on over 7000 acres compared to DCA's 860.  CVG has 55 direct flights compared to DCA's 108.   CVG averages 91 flights per day compared to DCA's 388.  Add in the amount of military air traffic around DCA, and those skies are constantly full.