Hi guys,I have a bit of a real world techie question for you.On the Honeyewell IVA81D IVSI with TCAS, when the range is changed does the inner circle range change or is that always 2nm.ThanksMark

Mark ,I cant vouch for the honeywell vsi ,but on our 737ng's the inner circle on the range display always stays at 2.5NM, as you increase the range of the map mode say from 20NM to 40NM the circle shrinks in size to be in scale with the rest of the display. Although this is on the ND and not a vsi style tcas I believe it would be the same.

Sorry, Mark...I can't recall what it does. I thought I had taken shots of ANZ's IVSI at both ranges, but I can't find the 12nm one. However, if you're not in a hurry, I might have an answer for you next week.http://members.ozemail.com.au/~b744er/767/ANZIVSI.jpgCheers.Ian.(I assume the above picture is similar to the type of TCAS display you are looking for?).

Ian,that's exactly what I was looking for.Wallace, thanks for providing an insight into the 737.Later Mark

The IVSI's on Northwests 757's do not change scale with the range select knob. The scale is always 6NM in front of the aircraft, 2.75 miles to the botton the the guage, and 4nm on each side. On the newer 757's and on the 300's the tcas is now integrated into the EHSI. There is a traffic button on the selector panel and of course, since it is an overlay it changes with the range.

Like so:

I see photos like this and I have to marvel at the accuracy of PIC.

Interesting shot, Iz.... I thought TCAS could only track targets up to a max range of 40nm. This pic shows a TCAS target at almost 100nm!Cheers.Ian.

Hi Ian,I think TCAS will track aircraft as far as it'll receive the signals, only the display options are limited. I've seen cockpits where the range is indeed limited to something like 40nm. Our 757's have all the upgrades available as fast as avionics/FMS/AFDS go. Even though our altitude range is fixed at +/- 2700 ft, not tiltable like in a 737NG, it will still track targets as much as 15000 ft below, I've noticed (eg. transponders without altitude reporting always show up, even though they're clearly much lower). On a slightly different note, I flight tested new aircraft systems and avionics at the Dutch National aerospace research center. It was modeled on the 777-type avionics with the new vertical situation indicator as shown in the latest Aero-mag. It was also outfitted for Free Flight (!) with a very advanced TCAS with conflict prediction. It shows other aircraft throughout the entire map range including direction of flight, groundspeed, aircraft type and predicts conflict and issues advisories (it's free flight) regarding vertical speed and heading. It worked VERY well, a magnificent system. It gives so much information about other traffic, also displaying it on the vertical situation indicator. Brilliant.Iz

Iz, speaking of new technology's ,we have an aircraft at boeing field called the "technology demonstrator" that has alot of emerging avionics. This is all installed on a standard 737-900.Technologies onboard the airplane include:Quiet Climb System (QCS) - Reduces community noise and pilot workload during takeoff by consistently and automatically reducing thrust over noise sensitive areas. (Boeing product)Vertical Situation Display (VSD) - Enhances safety by displaying the vertical profile of the airplane's flight path. Indicates the presence of terrain in the current flight path. (Boeing product)Navigation Performance Scales - Can minimize flight delays and increase airspace capacity by allowing the airplane to navigate through a much narrower flight path with higher accuracy. (Boeing product) Global Positioning Landing System (GLS) - A highly accurate satellite-based landing system that opens new airports and runways. (Honeywell supplied ground-based components; Rockwell Collins provided Multi Mode Receiver which supports GLS, SGS, SVS and HUD) Integrated Approach Navigation - Minimizes pilot workload and training by allowing a common approach procedures - reduces 18 complex approaches down to one. (Boeing product) Head-Up Display (HUD) - Expands operational capability and enhances safety by providing conformal flight path information to the pilot. (Rockwell Collins Flight Dynamics product)Surface Guidance System (SGS) - An emerging technology under evaluation that improves taxi safety and airport efficiency during poor visibility and darkness. Reduces the risk of runway and taxiway related incidents. (Rockwell Collins, Smiths Aerospace and Jeppesen products) Enhanced Vision System (EVS) - An emerging technology under evaluation that provides pilots with an accurate and clear view of obstacles, traffic and potential incursions at night and in reduced visibility conditions, thus enhancing safety. (CMC Electronics Inc. and Max-Viz products) Synthetic Vision System (SVS) - An emerging technology under evaluation that provides a computer-generated view of the outside world, enabling easy-to-follow paths for takeoffs, landings or taxi guidance. (Rockwell Collins product) Some of These will first be offered on the 737NG line early next year as options and will progress to the other Boeing models. It is really some amazing stuff.

Wallace, very interesting. Are you a Boeing employee, and if so, what is your job function?Interesting to see all these high tech add-ons added to the 737NG. We have I believe 20 in our fleet now and MAN, that airplane has some serious issues :) Glad to be on the 757! :)Iz

Yes, Iz I work for Boeing, My usual job is an electrician on these aircraft at the delivery center, as well as the 757. It seems like most of our customers are very happy with the NG, according to them it is very reliable. What kind of problems is your airline having with your NG's? Alot of the problems we have right now are with are vendors dropping disclosure letters on us telling us "hey these parts we have been making for you ,they dont meet FAA spec's." Almost every day there is a new disclosure letter,(fuel pumps recently) and this is really out of our control.Alot of these things used to be handled in house ,but Boeing has turned to outside vendors more and more for parts, that at one time were made internally.Is there a particular issue with your 737's? Are the issues being worked out for you airline?

Hi Wallace, well our airline (Transavia from The Netherlands) has had plenty of issues with them but since I'm not on the 737NG fleet, I don't know the specifics. What I'm talking about are the current 270 KIAS restriction, the troubles with the rudders, no speedbrakes above 300 KIAS etc. Sheesh! I know exactly why Boeing kept commonality with the older 737's and as such, created a hybrid aircraft with a little new tech and a lot of very old tech (although the 737NG pilots seem to think they fly the most modern of aircraft). In comparison, the 757 has been virtually trouble free, throughout it's production life. The main reasons many airlines go for the 737NG, despite its disadvantages (the cockpit ergonomics are from the stone age) is fuel economy (put new engines under a 757 by the way..) and fewer seats. With a 160 seat 757-100, you'd have a better aircraft with huge range, higher speed and more flexibility. :)Anyway, I'm not saying Boeing should build new versions of the 757. Even our systems are getting outdated now even though the systems, autopilot, performance, characteristics, range, ergonomics and cockpit are still better than the 737NG.I read about plans of starting a new program to replace the mid-size airliners 757/767 with a new type, sharing commonality with the 777. Do you know more about that?

Iz, yes the rudder issue is in work and we will get an aircraft shortly with dual rudder pcu's, and the 300kt speedbrake problem was originally for the -900 only ,the buffet from the speedbrakes was causing alot of horiz stab vibration above 300kt's, this is also in work at flight test.(what is the 270kt restriction you have).Its a love hate relationship to us also with the 737 ergonomics, I really like the 757 ,and I sometimes wish boeing would have completely re-designed the cockpit on the 737, the mix of modern and stoneage is a little strange. Like you say alot of airlines wanted to keep comonality with their fleets and Boeing adhered to their requests to keep alot of the cockpit and systems the same.There is talk of a modern medium sized aircraft, there's debate whether to build the sonic cruiser, but I think alot of the technology integrated into that will go into a much less radical design, such as a 757/767 replacement, as the specific's I cant really say right now .

Just to let you know why I haven't answered :-)All our international 767's have fixed range TCAS displays on the IVSI.Its only the aircraft on lease from BA that have the variable range display, and I never fly them, so dont know how it works.