Airplay From , joined Dec 1969, posts, RR: Reply 6, posted (9 years 2 months 1 week 4 days 12 hours ago) and read 4997 times:
There is quite a wide range of power outputs for VHF radios in aircraft. Generally, small aircraft transmit about 5 to 10 Watts whereas airline VHF radios transmit about 20 to 50 Watts. All depending on the model.
I'm talking RMS and not PEP.
My private aircraft (with airline type comm radios) has 30 watts carrier output, and these are over thirty years old.
This is quite a rare configuration. Small aircraft with powerful transmitters, translates into an RFI nightmare. Furthermore, 30 year old "airline" radios are rather heavy, in the order of 25 pounds. Why would you want to carry around 50 pounds of COM radios?
411A From United States of America, joined Nov 2001, 1826 posts, RR: 9 Reply 7, posted (9 years 2 months 1 week 4 days 6 hours ago) and read 4920 times:
1. That was the original fit, by the original owner.
2. The installation is top-notch.
3. I have had absolutely no problems with 'em whatsoever.
4. Not just comms either, navs, DME and the transponder are airline quality.
Heavy, yes...but this is not a concern in a large twin.
Airplay From , joined Dec 1969, posts, RR: Reply 8, posted (9 years 2 months 1 week 4 days 3 hours ago) and read 4880 times:
Just out of curiosity 411A, what are the model numbers of the avionics? Airline DMEs of that era weigh about 40 pounds and are about 3 feet long. The transponders are a little smaller and weigh a little less but are still monsters even for a "large twin". Both transmit in the Kilowatt range....
I have a feeling you have some remote radios that are Collins Pro-line or King Gold Crown and not "airline" quality radios.
There are a few Kingairs out there with airline ARINC equipment but they are pretty expensive to maintain these days.
411A From United States of America, joined Nov 2001, 1826 posts, RR: 9 Reply 9, posted (9 years 2 months 1 week 4 days 3 hours ago) and read 4871 times:
All King Gold Crown, Airplay and oddly enough, these very same avionics were installed in UAL 737's when UAL first got 'em, in the late sixties.
Last I heard, 737's were airliners.
In addition, many older KingAir's have these as well.
Total avionics weight in my aircraft is 97 pounds.
Considering I have a useful load of 2300 pounds, I can fill it up with fuel, 6 folks (including myself) and from SDL, FLL is only one fuel stop away.
Rather impressive for a 36 year old airplane.
Of course, spares for these older radios are not as plentiful as they once were, but I have several friends with these same radios, and if they need service, they ship 'em off to Tulsa for fast turnarould.
Airplay From , joined Dec 1969, posts, RR: Reply 10, posted (9 years 2 months 1 week 3 days 18 hours ago) and read 4830 times:
King Gold Crown is not "Airline". If in fact UAL had a few "oddball" 737s delivered with them doesn't change that. By the way, I seriously doubt your claim. Even 707s and DC-8s were equiped with airline equipment and not general aviation or business aircraft equipment of the era.
Is it possible that you are confusing your KTR-900 Gold Crown unit with the KTR-9000 Airline COM?
I am quite familiar with the Gold Crown series from this era and yes...many light aircraft were fitted with them as that is exactly the market they were developed for; light twins and business aircraft.
This particular series (KTR-900, KNR-600, KXP-750, KDM-700 etc...) are commonly found in older Piper and Beech twins and in some commuter aircraft but they are notoriously unreliable. Especially the transponder and the DME. They were however much more reliable than the standard avionics package usually delivered with Cessna twins.
411A From United States of America, joined Nov 2001, 1826 posts, RR: 9 Reply 11, posted (9 years 2 months 1 week 3 days 16 hours ago) and read 4815 times:
Hmmm, perhaps that is why I have had absolutely no trouble with 'em.
Then again, maybe i'm just lucky.
Strangely, when I was flying BE99's in the late sixties, never had any type of radio failure that I can recall, with Gold Crown equipment.
They proved just as serviceable as the Collins 618M's and 51RV1's fitted to the 707's I operated shortly thereafter.
Must be due to their 'notoriously unreliable' reputation.
Airplay From , joined Dec 1969, posts, RR: Reply 14, posted (9 years 2 months 1 week 2 days 16 hours ago) and read 4639 times:
411A, you are a unique individual. First you say;
Firmly believe, if it ain't broke, don't fix it.
Then you follow up with;
I do better than that, I have 'em removed and bench checked/tuned every two years. If you maintain 'em, they will last and last.
I state that the old series of Gold Crown is notoriously unreliable. You state;
I have had absolutely no problems with 'em whatsoever.
......and these are over thirty years old.
So you have 30 year old radios that you have never had a problem with and they have never broken because you continuously fix them...
The only downside to these radios is that the comms cannot be up-graded to 8.33 spacing. However, as the US (wisely in my opinion) is not likely to do this...no problems.
Actually, the US will eventually adopt some type of new channeling to increase the number of channels available. The unfortunate thing is the FAA is currently exploring a digital solution that would add the exact number of channels the lo-tech european solution offers.
The digital solution will completely replace current VHF transceivers. But then again, the KTR-900 as well as many other VHF COMS have been on the way out for quite awhile since the FCC passed new spectrum management rules in 1997. By the way...did you know you can't license your KTR-900 for transmision in the US and that you'll have to have it replaced by 2007?
Airplay From , joined Dec 1969, posts, RR: Reply 16, posted (9 years 2 months 1 week 1 day 19 hours ago) and read 4515 times:
411, Wrong again. I have worked for an airline, and avionics equipment is generally replaced on condition. Like you said, "if it ain't broke, don't fix it."
Of course, there are exceptions. CVR and FDR equipment as well as air data equipment, transponders and ELTs are subject to regular inspections ranging from 6 months to 2 years.
VHF/HF COMs, VHF NAVs, ADFs, DMEs, GPS, FMS, audio panels/PA, weather radar, instrumentation, AHRS/DG/VG/IRS, autopilot/FD, TAWS, TCAS are typically on condition. Some systems like TAWS and TCAS have mandatory pre-flight tests but are otherwise on condition.
Of course like everything in aviation, there may be exceptions to some of what I've written, but generally its all correct.
411A From United States of America, joined Nov 2001, 1826 posts, RR: 9 Reply 17, posted (9 years 2 months 1 week 1 day 15 hours ago) and read 4492 times:
So as you can see, Airplay, we do it slightly differently here.
I generally find that the operation of older equipment is enhanced by regular inspection, and in the case of older avionics, a bench check from time to time is recommended, for uninterrupted service.
Works for me.
Now on the other hand, if I were looking for newer avionics, the Garmin 430/530 are hard to beat. A nice package, all in one box.
Having said this, I am certainly not about to discard older equipment just because it is not the latest and greatest.
Iakobos From Belgium, joined Aug 2003, 3310 posts, RR: 36 Reply 20, posted (9 years 2 months 1 week 22 hours ago) and read 4374 times:
As an electronics engineer, I stand by my statement.
It is not an assumption to say that an electronic component can fail at any time and that there is no way to know it beforehand, it is a fact.
It is only slightly different with mechanical components (eg. switches), which have an expected lifespan expressed as a number of cycles, and for which timely replacements are a way of prevention.
I suspect that some critical (especially the not redundant) devices, as mentioned by Airplay, are timely going through a renovating procedure whereby some components (perhaps at board level) are replaced.
The test bench measures the performance and characteristics of the device under test. It does in no way prevent something going wrong the next second.
If you wish to have the last word, the field is yours.
Airplay From , joined Dec 1969, posts, RR: Reply 21, posted (9 years 2 months 1 week 17 hours ago) and read 4354 times:
If we were to carry thru to the end with your assumptions, NO airbourne equipment would ever be inspected...one would just wait for it to fail, oftentimes at a rather inappropriate time.
Airborne equipment that is subject to regular inspection is typically part of a critical system whose failure rate must be at least improbable to prevent a major hazard. That is why the vast majority of communications or navigation equipment is maintained "on condition". For light aircraft, there is no major failure attributed to NAV or COM equipment except for hazardously misleading guidance information and that instance is generally proven to be extremely improbable.
You simply cannot compare a NAV or COM or DME etc with critical systems like flap controllers or PCUs.
The Garmin stuff is nice. But I've seen GNS-430s fail right out of the box. Furthermore, Garmin's repair/exchange program is kept quite busy. Parts is parts....
Iakobos is of course correct. For electronic equipment the rate of failure remains unchanged for units that have just been through the shop. Some studies actually suggest that your rate of failure increases when you remove serviceable equipment for test because you suddenly introduce a variable.
411A From United States of America, joined Nov 2001, 1826 posts, RR: 9 Reply 22, posted (9 years 2 months 1 week 16 hours ago) and read 4351 times:
Several years ago, during a bench check of one of my KTR-900A's the tech noted several older discolored components, and replaced these rather than leave them in.
Now of course, the new ones could have failed right away, but they of course, did not.
I firmly believe that with older avionics, a bench check from time to time will prevent (or help to prevent) an AOG condition, and resultant out of base expense.
I would much rather pay a little now rather than a lot (as in, inconvenience) later.
You pays your money...takes your chances.
And then we come to the discussion of glass, and the possible retro-fit in older aircraft.
Three years ago, the local owner of a Lockheed JetStar decided to replace his steam gauges with glass, and also the older Collins avionics as well.
The techs cut all the old wiring harnesses out and proceeded to install all the new boxes, instruments, etc.
When it was all completed, it sure did look nice, but strangely enough, it didn't work all that well in flight.
So poorly in fact, that the FAA would not certify the installation.
So, the new boxes went out and the old back in...with new harnesses from Lockheed, which still supports the JetStar, oddly enough.