Another Side of the Story
TCAS Resolution Advisory (RA)
Our Company’s procedures for a TCAS RA are identical to Airbus’s procedures to my knowledge, and that is:
AUTOPILOT –-------------- OFF
BOTH FLIGHT DIRECTORS -- OFF
VERTICAL SPEED –--------- ADJUST TO THE GREEN (promptly & smoothly)
Note: Avoid excessive maneuvers ....
Apparently the TCAS systems are designed to give the pilot(s) 5 seconds to respond to a primary RA (Resolution Advisory) which is carried out only in the vertical plane (eg no turns). In the unlikely event of a secondary TCAS RA occurs (you’re diving or climbing into the path of a third aircraft) while carrying out the first RA maneuver (nightmare scenario) the pilots have 2 1/5 seconds to respond correctly to the secondary RA.
5 seconds is a fairly long time so there is no need to rush it, but also there is no time to sit on your hands either. Just a normal disconnect of the A/P and F/Ds - OFF then push or pull gently in the direction that TCAS is directing. TCAS events should be part of every simulator training and license renewal, but unfortunately they are not. If they were, then line pilots would not get startled at an occasional real world RA occurrence and possibly overreact.
Granted, if an RA occurs and at that same instant you fly under a dark cloud that shadows the flight deck and the unexpected combination sends a chill up your backside, thinking another aircraft is descending onto the flight deck from above, you might over-react and shove a bit too fast and too hard on the yoke or side stick. That’s a natural human adrenalin response to fear invoking situations. (P.S. Pilots are human too.)
The quick abrupt response of the Taiwanese pilot would have been correct and would have saved lives if there really was an aircraft present and descending onto his flight deck from above, but the identical same pilot actions are easily criticized by the Media, Management, Safety Review Boards, etc, if there was no other aircraft; just the perception of one.
In my early days of flying, I climbed out of a small uncontrolled airport with no radar coverage and well before TCAS was invented. During climb passing 3500’ a sudden shadow above the aircraft caused me to look up abruptly through the eyebrow windows to see the underbelly of another aircraft a few meters above us. The other aircraft had flown overhead the airport without seeing us taking off below because we were below his line of sight over the glare shield. We did not see him because he was above and behind us.
Only my quick abrupt response of pushing the nose down and pulling off power avoided a mid-air collision, but all onboard floated up against their seat belts with the negative g's produced. The two aircraft could only have missed one another by a few feet. And yes everyone thankfully had their seat belts fastened so no one got hurt.
It’s easy to throw stones at pilots that have to make split second decisions during a “oh-!!!!!” moment, but that’s why we get paid the big bucks (or the little bucks as the case may be). Our lives and the lives of the crew and passengers depend upon the pilot’s quick reflexes tempered with experience and training.
Be that as it may, if no one had gotten hurt in the TCAS RA event executed exactly as the Taiwanese pilot referred in the primary article did, then the ASC investigation, if any at all, would have centered on the Inchon ATC under-staffing, or inattention due to overloading in his sector, or lack of procedures, or lack of supervisory oversight, that contributed to the circumstances that produced two aircraft at the same level and then giving contradictory ATC instructions using the wrong call-sign numbers.
Seatbelts fastened make a heck of a lot of difference to outcomes under such unexpected circumstances.
I hasten to add that the Cabin Crew working the cabin and galleys would have still been vulnerable to injury even if all passengers had been belted in, and therefore, such abrupt maneuvers must be avoided as much as possible in airline operations.
That’s another side of the story to consider. Cheers, Magnet77
Last edited by Magnet77; 18th August 2008 at 11:13.