Midair Warning

On Wednesday, July 15, 2015 at 9:34:31 AM UTC-7, wrote:
/snip/


I'm no expert but in reading through the discussion above, short of the F-16 carrying TCAS, it doesn't sound like any of the current equipment would have prevented this collision.

TCAS is certainly impressive and proven technology, but I don't think you can claim that an F-16 with TCAS would have "prevented" this collision. We don't know the important details about how/why the collision happened. AFAIK it is still not clear if the Cessna 150 transponder was actually operating--was it actually turned it on? Was the encoder reading the correct altitude? Was the Transponder correctly set to Mode-C/S (not Mode A aka "ON" on many transponders... then a TCAS would not "see" the Cessna at all). Did the F-16 have its radar on/in what mode? IFF interrogator on?/in what mode? (I am pretty sure the BAE IFF/Transponder in the F-16C is capable of interrogating Mode 3C/S so can receive back target altitude if in the appropriate mode, but I have no clue what is actually displayed to the pilot in what mode). I could go on for paragraphs more with questions, there are many questions about equipment, ATC and the pilots working correctly. Some answers to which would imply having a full TCAS-II in the F-16 would would not have helped.

There was a horrible accident and some kind of failure that absolutely needs to be understood, and I want to wait to see that finding, but I suspect this may just be a case where the aircraft were suitably equipped and bad still bad things happened and bolting yet more technology on may not necessarily be the right way to move forward...

Summary after one flight: FLARM is a nice addition to the cockpit but doesn't confer immunity from collision with anyone or obviate the need to keep looking around. It also provides some tactical info on nearby gliders that changes the game in small but significant ways.

FLARM was *never* intended to reduce the importance of visual lookout. I don't think (and hope that) anybody who flies with FLARM has the expectation that it confers any "immunity". It is a supplement/enhancement to make up for the inherent and serious problems in visual avoidance especially with gliders. Interestingly the whole development of FLARM started by looking for ways to reduce mid-air glider collision risk, including high-visibility marking, etc.

No technology (including TCAS) can provide immunity from collision risks. Nobody should be expecting that, and describing any saftey related product as not *perfect* is really not a useful way to think about saftey. It needs to be a more nuanced discussion about risks, technology benefits, effectiveness and costs. An area that has been well covered for FLARM. including Andy Blackburn's article in Soaring Magazine last year.

I understand you pain on the cost of all this, and we've got to be careful moving forward, with PowerFLARM, Transponders, ADS-B and maybe TABS all offering different capabilities, some being fairly clearly useful in some cases but just bolting in more and more technology does not necessarily keep providing a useful improvement in saftey, let alone saftey value for money. Especially as some of this stuff just becomes incompatible/risks overloading/distracting the pilot or just confusing owners/pilots on what the actual capabilities of all these technology boxes are...

Great to see you got offers for PowerFLARM loan/rentals for your contest.

On Wednesday, July 15, 2015 at 11:39:38 PM UTC-4, Darryl Ramm wrote:
On Wednesday, July 15, 2015 at 9:34:31 AM UTC-7, wrote:


TCAS is certainly impressive and proven technology, but I don't think you can claim that an F-16 with TCAS would have "prevented" this collision. We don't know the important details about how/why the collision happened. AFAIK it is still not clear if the Cessna 150 transponder was actually operating--was it actually turned it on? Was the encoder reading the correct altitude? Was the Transponder correctly set to Mode-C/S (not Mode A aka "ON" on many transponders... then a TCAS would not "see" the Cessna at all).


Just a slight correction. TCAS does indeed see mode A transponder returns. It obviously can not see the altitude of said transponder as there is no mode C altitude information being interrogated. So the TCAS will display the target range and bearing information and if there is a potential collision it will issue a TA or Traffic Alert audio warning and the target turns yellow. Since TCAS needs the altitude information in order to compute a climb or descent escape maneuver or RA Resolution Advisory, TCAS will not provide that as it would if the target were mode C equipped and operating. So the pilots eyeballs are the only defense. This is often frustrating as you can be flying in the flight levels and be get a TA warning for non mode C traffic in a airport traffic pattern 10,000' plus below. That said I'd much rather get the warnings and drive the pilots eyes outside and in the direction of the threat to scan all close altitudes than not know about it. Cheers.

Couple of points. As Kirk pointed out, and he is correct, IFF interrogators in fighters do not provide altitude information, only bearing and range. This system is also manual and needs to be activated to interrogate.

The military follows the rules more than many might think or want to believe. The only times they do not is when their TO's (POH) states the speed requirements, and they have a waiver. Also as mentioned, speed limits do not apply when they operate within the confines of MOAs, restricted airspace, warning areas or MTR routes. However, fighters must schedule MTR routes, and local FSSs are aware of the scheduled use of these routes.

As to ADS-B, working in DoD Acquisitions, I can tell you the USAF is trying to comply with this new requirement for all aircraft. However, an FAA mandate does not provide any funding, just like it doesn't for you either if they mandate transponder use for gliders. Trying to fund solutions for the military community is very problematic in the current budget environment, but the goal is to make it happen, it will just take a lot longer in the current budget climate if the military wants to keep its eroding capabilities over providing warnings to civilians while flying in the US for training missions.

FWIW, Garmin just announced the GPS-20A, a TABS-compliant non-certified ADS-B WAAS position source for $845 ($1225 with antenna and install kit). Whether or not we end up up having to deal with the ADS-B mandate, we really should be pushing the FAA hard to allow TABS equipment to be installed in certified gliders.

Marc