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View Full Version : TCAS In 'E' = Last Line Of Defence???


Ex FSO GRIFFO
29th Dec 2010, 09:31
From today's AvWeb.....

If YOU had one of THESE units, and was 'reliant' on it for your 'LAST Line Of Defence' in "E" Airspace....

Oh Dear...

"Some TCAS Units Miss Traffic, FAA Says

The traffic alert and collision avoidance systems used in thousands of aircraft need to be upgraded, the FAA said this week, to prevent them from missing targets in high-density areas. During a flight test, a TCAS unit built by Aviation Communications & Surveillance Systems (ACSS) dropped several aircraft tracks because of interference limiting, the FAA said. The dropped tracks could "compromise separation of air traffic and lead to subsequent mid-air collisions," according to the proposed airworthiness directive. The fix will cost about $3,000 per airplane, the FAA said. The units are installed on about 7,000 aircraft operated by U.S. airlines and more than 1,800 business aircraft, an FAA spokeswoman told The Wall Street Journal.

The FAA said that during a flight test, the TCAS unit interrogated aircraft in a high-density airport area and some of the targets disappeared from the cockpit display or were not recognized. One occurrence of dropped tracks occurred for 30 to 40 seconds of a 90-minute flight segment. Operators have 48 months after the effective date of the AD to install the software upgrade. A spokeswoman for L-3 Communications, the parent company of ACSS, told the Journal that the company informed the FAA of the problem in the summer of 2009, and has been working on a fix. Service bulletins already have been issued to deal with it, she said."

Just for info.......:ok:

Wally Mk2
29th Dec 2010, 10:14
'Grif' that is indeed a worry, I hope I'm reading all that wrong!

YMAV is the perfect Eg. of shear madness in Aussie Airspace. There's already been many TA's there & a few RA's & with the joint now having 'E' from 700' agl to 4500' (outside twr hrs) means it's damn scary! Lets hope that those particular units are not in use around here.


Wmk2

Jabawocky
29th Dec 2010, 10:15
chances are.......... vannishingly small :oh:

Joker 10
29th Dec 2010, 12:28
I wonder why we have windows ?????

Jabawocky
29th Dec 2010, 12:56
I wonder why we have TCAS ?? :ugh:

Was it a PSA 727 Vs C172 and lots of dead people scattered all over San Diego?

Most likely they had the optional windows fitted. :hmm:

Ex FSO GRIFFO
29th Dec 2010, 14:00
Tks 'Jaba'....:ok:

And for those 'Younguns'...who haven't quite 'caught up'.....

PSA Flight 182 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/PSA_Flight_182)

Read and Learn is all I can say.......

p.s. THANKS DICK!!!

Joker 10
29th Dec 2010, 22:11
Jaba as you said in a previous posting, Vanishingly Small risk.

TCAS is a great technology but it is electronics and algorythms.

Windows are old technology less prone to the vagaries of gremlin failures.

Both , used together are a better defence that each on their own.

Jack Ranga
29th Dec 2010, 22:35
Joker 10, I'm assuming from your responses that you find PSA182 acceptable risk, so long as it only happens once every say, I dunno? 10 years or so?

Or are you saying that the B727 pilots were incompetent because they 'didn't see' the 172?

Biter
29th Dec 2010, 22:35
The other is problem is E airspace rules:ugh:

Wally Mk2
29th Dec 2010, 22:51
The trouble with TCAS is it's only as good as those using/believing it.
The DHL/Tu154 accident some years ago is the perfect Eg of that. The pilots would have been shocked to see that they where in conflict with each other out there at night in almost vacant skies over Europe but there was other mitigating factors involved (equip off line for maint etc. Awful story that one, very sad:-(
It does show that TCAS although is a great tool can just be another tool that makes the pilots 'toolbox' heavier.

Windows are great if yr visual! TCAS doesn't know if yr vis or not.

Wmk2

Jabawocky
29th Dec 2010, 22:56
Joker

Have you thought the :ugh: meant something?

When you have YMAV with unknown lighties buzzing across the ILS with goodness knows what distance from cloud and a typical OVC for Melbourne, its no wonder Wally is not happy!

Joker 10
29th Dec 2010, 23:59
Rangs, Joker 10, I'm assuming from your responses that you find PSA182 acceptable risk,

Not at all, I merely pointed out the TCAS and windows are BOTH together acceptable defence

Joker 10
30th Dec 2010, 00:01
Jaba read Wally's post properly