Today in History….the birth of TCAS

[Shore Guy]

Today in History:

Date of Accident: 25 September 1978
Airline: Pacific Southwest Airlines
Aircraft: Boeing 727-214
Location: San Diego, California, USA
Registration: N533PS
Flight Number: 182
Fatalities: 137:137 + 7
MSN: 19688
Line Number: 589
Engine Manufacturer: Pratt & Whitney
Engine Model: JT8D-7B
Year of Delivery: 1968
Accident Description: The aircraft crashed into the residential area of North Park after colliding with a Cessna 172 (Gibbs Flight Service) while making a visual approach to runway 27.

Full report available at: http://amelia.db.erau.edu/reports/ntsb/aar/AAR79-05.pdf

[ironbutt57]

Took 'em a long time to sort out tcas...if it is today....lost a few friends including my special lady onboard PSA 182, then lost two colleagues, friends, and ultimately a job over misuse of tcas over Uberlingen 2+ years ago

[Flying Mech]

A lot of things in Aviation are learned the hard way from the experiences and mistakes of others. It is terrible to think that it took the loss of 137 lives 26 years ago to start the development of TCAS, however I am sure that over the years it has saved 100 maybe even 1000 times that many.Tcas is a great safety system which has saved my own Bacon on adeparture out of PHC (Port Harcourt Nigeria) a few years ago when ATC cleared a 767 to land as we were on climbout in a A300 meeting each other. All ended well but ther were a few skid marks on the cockpit seats that day I can tell you! Another shining example of ATC in Africa

[ironbutt57]

Don't use the words "ATC" and "Africa" in the same sentence!;)

[PLovett]

Flying Mech

That collision over southern California in 1978 didn't start the development of TCAS, it only started the political push for mandatory installation.

The development of TCAS goes back a long way but it has taken a couple of collisions to hasten its development. They include one over Arizona between a DC-7 and a Lockheed Super Constellation and another between a Super Constellation and a DC-8. :ok:

[FlexibleResponse]

According to Colleen O'Hara of Rannoch:

http://www.rannoch.com/TCASFCW.html
Overcoming Growing Pains

The idea for TCAS dates to 1956, when two planes collided over the Grand Canyon, and airlines realized they needed a collision avoidance system. TCAS is an outgrowth of a system developed in the 1970s that was called the Beacon Collision Avoidance System and used transponders located on airplanes. The system was replaced by the family of TCAS systems in 1981.

The success of TCAS is attributed to an unusual level of cooperation between the FAA and the airlines. FAA funded most of the development and design of the system. Mitre developed the system logic, and the FAA Tech Center and a team of contractors handled software verification and validation and performed operational tests. MIT Lincoln Laboratory developed air-to-air surveillance.

TCAS, like most complex systems, had its growing pains. "When TCAS was deployed, there were a lot of nuisance alerts, and pilots and controllers were losing confidence in the system," said Andy Zeitlin, principal engineer for avionics at Mitre CAASD. "We changed the system to fix that, and the results were dramatic." Version 7 of TCAS, which reduces the number of false alarms, was approved in December and will begin appearing as early as the end of this year.

"TCAS is a good example of [what good can be done] when we work together in the interest of safety," said Albert Prest, vice president of operations at the Air Transport Association.

"TCAS is an industry program that would not have occurred without FAA leadership," said Capt. Robert Buley, a pilot and manager of flight technology development at Northwest Airlines.

"If it were not for a congressional mandate, we would still be designing this. Had we not had the mandate, there would have been more collisions we would have had to live with," Buley said.

Buley has been involved with TCAS in one form or another since the 1970s. He is chairman of the RTCA standards committee that led the TCAS standards-and-design effort. All the time devoted to TCAS has been time well-spent, he said. "I will be walking down an airport concourse and a pilot will stop me and shake my hand and say, 'Thanks for TCAS,' " he said. "I even get calls from overseas."

There's no question TCAS has saved lives. Since its introduction, the number of reported near collisions has dropped, said Larry Nivert, the FAA's TCAS program manager. "There is a correlation between the date TCAS was introduced and now and the drop in near midair collisions. It's certainly an indication that TCAS has had a positive effect."
”Thanks for TCAS!”

[West Coast]

TCAS
Don't leave home without it.......

One of the very real outcomes of the PSA crash was the development of the TCA, now class B airspace around busy air carrier airports.

[ironbutt57]

The "TCA" Terminal Control Area, had been in use at most major airports for quite some time prior to PSA..San Diego after the accident was "provided" with a knee-jerk Group 1 tca which covered the whole place basically with no vfr corridor provided to transit the area north-southbound, so the small airplanes were all relegated to the chore of flying around the new TCA east of the area in close proximity to the high terrain, (and each other), after much squabbling and complaining, the FAA relented and provided a vfr corridor not unlike the one directly overhead LAX at the time to alleviate the headaches being suffered by GA pilots. To put it into perspective, the TCA at LAX had a ceiling of 7500 feet, whereas the new TCA at SAN was up to 12,500!! Light plane pilots were definately the bad guys in the eyes of the public for quite some time following the accident, and unfairly so, as many factors were involved in the collision, primarily the "see and avoid" principle which was in effect, as PSA had reported having the Cessna in sight..mistakenly so...got a good pix shot by an acquaintance that i downloaded off of air disaster.com which shows the final few seconds of the 727 about 300' in the air..don't know hpw to attach it...