CG...you're not suggesting they'd 'do a smiff' on us are you?
I agree that the D/E interface will be a potential disaster area. I tried posting this last night but got 'server to busy..' I'll use MC as it's one of snarek's bugbears.
My hypothetical;
Chap rents a 30 yr old C172 from Redcliffe to take family on a weekend trip up the coast somewhere. Having read carefully the NAS package he selects 'alt' on the mode C as he lines up on 07.
A strong SE wind is giving him a great GS as he heads north.
8 Dme MC he changes to MC TWR freq but just misses out on hearing takeoff clearance being issued to a Flying College LR45 which is being flown by a 300 hr cadet and an Instructor.
Something along the lines of "SQxxx maintain FL170, rwy 18, clear for takeoff, make left turn, contact Brisbane Radar 125.7 leaving 6000."
The cadet takes a good 30 seconds to settle himself before pushing up the thrust levers. Neither he nor the instructor notice a TA on the TCAS as the sun's shining on the IVSI and the instructor was destracted with line up checks, acknowledging takeoff clearance and final 'hints' to the young tyro in the RHS...it only being his second ride in the Lear pocket rocket.
By now the C172 is a little north of Point Cartwight over water as the pilot is carefully avoiding the runway approach/departure and is hoping to spot some whales for his kids to see.
As our cadet hit's 500' he curves left onto 090 to pick up the 120 radial on initial climb to FL170. As he rolls out on heading the aircraft is accelerating through 250kts and is climbing at 4000'/min. Within seconds he's curving right in an attempt to capture the 120 radial cleanly, and now above 1000' and they get an RA. For this readers not familiar with TCAS RAs are not given below 1000' so that they don't fly you into the ground.
Precious seconds pass as they sort out what's happening and, with the instructor pushing on the controls as well they get the needle in the IVSI into the green arc while searching for the threat aircraft.
A C172 appears in the windscreen passing agonisingly slowly from right to left and...too late... the left wing of the Lear hits the tail of the 172....they both spiral into the sea several miles apart.
What happened?
Why didn't TCAS and 'see and avoid' stop this tragedy?
Well the C172 pilot felt pretty safe at 4500' so close to the runway....what can climb to 4500' within 6nm?
He was also distracted by his 8 year old throwing up down the back of his neck.
What about the Pros in the Lear 45?
Well they were busy as f**k quite frankly.
The cadet was trying to drag his brain from mid cabin while the instructor had glanced down to check the gear and flaps were 'up lights out', the pressurisation was working & climb power set. He was coaching his cadet and selecting 125.7 to the active frequency so he could call Brissy approaching 6000 (in about 15 seconds from now)...all in preparation for the cadet to call "After takeoff checklist" (hopefully, remember his brain is just aft of the fwd galley by now) after established on track/above MSA and establishing two way comms with Brissy.
But they got the IVSI in the green arc...they should have (just barely) missed the 172?
Well after dragging the two aircraft from the sea and checking maintenance records ATSB's best guess is that perhaps the transponder was transmitting an altitude a little higher than actual. It hadn't been checked for over 10 year as there is no such requirement for VFR aircraft.
Or perhaps the 172 pilot saw the LR45 in the last few seconds, nose high and clearly climbing at an unbelievable rate, and in a reflex shoved the controls fwd to avoid the midair...thereby rendering the TCAS RA useless.
What could have stopped this chain of events?
"Maroochy twr, ABC, Moffet head 2500 for Hervey Bay, request airways clearance".
"ABC maintain 2500, track direct to the field, taffic is a departing LR45 rolling shortly rwy 18, left turn"
"Direct the field, 2500, ABC"
SQxxx- Maroochy twr, Traffic is C172, 6nm south at 2500', maintain 1500, rwy 18 clear for takeoff make left turn"
Couldn't happen?
Well that's not the experience in the US.
Chuck.
editted for snareks last post. Just yesterday spoke to an experienced grade 1. She was horrified by the NAS package and suggested that was not an uncommon reaction by the other instructors she knew!