speedbird52
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What airlines fitted 727s with INS?

Sat Apr 08, 2017 4:07 am

I was quite surprised to learn that most 727s were not fitted with an INS. I find it hard to believe that in the late 90s and early 00s planes were flying around using only vor-vor. Did any major US airlines fit theirs with INS systems?
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Max Q
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 5:35 am

All we had in most of ours (Continental) were 2 VOR receivers with DME and 2 ADF's.


Heading to Mexico over the Gulf you were basically dead reckoning for the 'middle part'
Same going down the AR routes off the east coast, hard to believe even when we were doing it,
basically they were too cheap to install any kind of area nav in those days as you didn't
need it for the most part.


A few of our -15 models had Omega and later, in their last few years were fitted with GPS.


I think Dan Air may have had INS installed on their 727's.


Don't know of any US operators that did.
The best contribution to safety is a competent Pilot.
 
BravoOne
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 1:52 pm

Singapore had dual Carousel IV in their 727-212Adv. There were probably a few operators that installed Omegas at a later date after they were handed sown to the 2nd tier operators. The early INS was both expensive and not that reliable from a Mean Time Between Failure number. There was a time when Delta was getting around 1000 hours MTBF on the Carousel's in their L1011s.
 
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DL_Mech
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 3:47 pm

Delta installed a single Omega unit (removed from L-1011s) in the mid '90s in the 727s, but quickly deactivated them when the Omega stations were shut down in 1997. No INSs' were ever installed in DL 727s (including the FRA based ones).

This plane is built to withstand anything... except a bad pilot.
 
BravoOne
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 5:35 pm

I don't recall ever seeing an Omega in the L1011? Not doubting your word, just don't remember that config. Probably after having all the issues with the Carousel lVs? I assume they must have left one INS in place for the inertial platform?
 
speedbird52
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 6:04 pm

Bit of a noob question: But what was the omega system?
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BravoOne
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 7:12 pm

speedbird52 wrote:
Bit of a noob question: But what was the omega system?



Google is your friend. Land based long range navigation system used extensively between around 1970 and 1990/ You can Google Litton LTN211 for a point of reference.
 
speedbird52
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 7:43 pm

I did indeed Google but I did not understand it well. Was it an alternate to the Carousal?
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DL_Mech
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 7:55 pm

BravoOne wrote:
I don't recall ever seeing an Omega in the L1011? Not doubting your word, just don't remember that config.


I believe it was dual Litton Omegas on the domestic L-1011. The last ones were being removed when I hired in (1990), but the blanking plates for the antennas were left behind the nose gear. Triple Delco Carousel IV INS, FMS and Windshear/TCAS installations were going full bore around that time.

All of the Eastern L-1011s had the Litton Omegas, but DL never utilized them. Those planes flew for a few years VOR-VOR until the triple Delco Carousel IVs were installed.

Image
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BravoOne
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 8:08 pm

Some airlines used both an INS, (Carousel or LTN51) and a single Omega. The INS was retained because it created the platform for some of the flight instruments, most notably the horizon, aka flight director. If the airplane was delivered with dual INS, the operator could replace one of the INS units with a stand alone Omega such as the LTN211. MUCH cheaper to operate based on the high MTBF they experienced with the INS. Not all airlines did this but some did. American Airlines was one that did this in their DC10's. Maybe just the DC10-10 I don't know, but its a pretty common practice as the original INS units aged and started to fail more frequently. Both the LTN 51 INS, and the LTN 211 had similar operating procedures although unlike the INS, the Omega could have drop outs that would cause periods of dead reckoning until it got back in the game. In the mean time you had the single INS keeping track of your position. The issue at hand was you were supposed to have 2 Long Range Nav systems working for the oceanic crossings and this was a dispatch requirement. I think there were DC10 operators that used dual Omega but I'm not sure how they handled the absence of an inertial platform for all the other supporting roles?
 
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DL_Mech
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Re: What airlines fitted 727s with INS?

Sat Apr 08, 2017 11:34 pm

BravoOne wrote:
Some airlines used both an INS, (Carousel or LTN51) and a single Omega.


I remember seeing that on a BWIA L-1011. 2 INS's/1 Omega.
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FlyHossD
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Re: What airlines fitted 727s with INS?

Sun Apr 09, 2017 12:15 am

Max Q wrote:
...A few of our -15 models had Omega and later, in their last few years were fitted with GPS...


CO did invest in GPS/FMS systems for the GUM based 727s (both -15 and -17 powered aircraft, i.e. all GUM 727s). As I recall, it was the Honeywell Trimble HT-9100 and the MNL based freighters had the HT-9000.
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BravoOne
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Re: What airlines fitted 727s with INS?

Sun Apr 09, 2017 1:00 am

The DAL L1011-1's had the dual INS that interfaced with an FMS with a Nav Data Base. These were pretty much HNL dedicated airplanes. The L1011-250 did not have the FMS interface units as I recall so you were limited to nine waypoint and the you needed to update the programing. Did not see those on the west coast island routes very much.

If you wanted to see something really strange it was the DC10-30 that Western operated for a few years, Collins AINS70 Triple Inertials with area nav. Former ANZ airplane.
 
Max Q
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Re: What airlines fitted 727s with INS?

Sun Apr 09, 2017 5:26 am

FlyHossD wrote:
Max Q wrote:
...A few of our -15 models had Omega and later, in their last few years were fitted with GPS...


CO did invest in GPS/FMS systems for the GUM based 727s (both -15 and -17 powered aircraft, i.e. all GUM 727s). As I recall, it was the Honeywell Trimble HT-9100 and the MNL based freighters had the HT-9000.



Interesting, I flew several of the Air Mike routes in the 767 but I didn't fly the 727 out there, makes sense they had a decent long range nav system.
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RetiredWeasel
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Re: What airlines fitted 727s with INS?

Sun Apr 09, 2017 2:38 pm

As I stated in another thread, NW 727s that flew out of Guam from 93-96 were outfitted with dual Omegas - Trimble TL-7900. It had a pretty decent computer and emulated somewhat an FMS that was showing up on the more modern aircraft. It was about the only piece of 'glass' instrumentation that I ever saw in the 727.
http://www.decadecounter.com/vta/pict15/ta7900_1.jpg
NW never installed any INS in the three-holer. Towards the '96 time frame, I heard that the CO 727s in Guam were getting GPS's.
 
FlyHossD
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Re: What airlines fitted 727s with INS?

Sun Apr 09, 2017 3:46 pm

Max Q wrote:
FlyHossD wrote:
Max Q wrote:
...A few of our -15 models had Omega and later, in their last few years were fitted with GPS...


CO did invest in GPS/FMS systems for the GUM based 727s (both -15 and -17 powered aircraft, i.e. all GUM 727s). As I recall, it was the Honeywell Trimble HT-9100 and the MNL based freighters had the HT-9000.



Interesting, I flew several of the Air Mike routes in the 767 but I didn't fly the 727 out there, makes sense they had a decent long range nav system.


The GPS' were initially used to replace the Litton(?) Omega long range nav systems, but Air Mike later received approval to conduct GPS approaches, too. This was a huge improvement over the prior NDB approaches to several of the island destinations.
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longhauler
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Re: What airlines fitted 727s with INS?

Mon Apr 10, 2017 4:52 pm

Air Canada equipped five 727-200s with INS for Caribbean operations in low season. They also had 6 Y seats removed and life rafts placed in their place, as well as HF radios and survival gear. (All AC 727s already had life jackets).

This sub-fleet is much like the 4 A320s and 5 A319s that AC currently flies to the Caribbean today, in addition to the two ETOPS120 equipped A319s for LHR operations.

If you had ever flown on one, you would see a unique safety card, labled B727M, (or A319M, A320M) for overseas operations.
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113312
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Re: What airlines fitted 727s with INS?

Wed Apr 12, 2017 5:01 pm

VLF/Omega is a nav system based upon ground based signals. Once the signals were received and synchronized to accurate time, accurate latitude and longitude could be derived for navigation. INS is an onboard system that once aligned and given an accurate starting point, could use motion and gravity to calculate changes in position. Most systems incorporated means to update accurate position from ground based DME.

During the 1980's, I flew a fleet of 727s, for a charter operator, that used dual Marconi VLF/OMEGA nav systems that we effectively used for international and overwater navigation. At FedEx, we had a very large fleet of 727s. Only a small number had LTN-92 INS installed initially to fly the north Atlantic and later mainly for use in South America. The majority of the fleet only had VOR/DME
 
Max Q
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Re: What airlines fitted 727s with INS?

Thu Apr 13, 2017 5:09 am

Just to clarify, you say FDX had a small number of 727's installed to fly the North Atlantic.


You mean to ferry them over and back for use in Europe I assume, not carrying packages there ?
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RotateAero
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Re: What airlines fitted 727s with INS?

Fri Apr 21, 2017 5:52 am

727 maintenance for over 20 years. Never once did I see one with INS.

Domestic flights mostly over land where VOR/DME worked just fine.

INS usually associated with distance flights over water.

Continental Micronesia (to the best of my failing memory) did not have them installed either.

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longhauler
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Re: What airlines fitted 727s with INS?

Fri Apr 21, 2017 4:35 pm

RotateAero wrote:
Continental Micronesia (to the best of my failing memory) did not have them installed either.

Do you know what they did use?
As some of their legs were beyond VOR/NDB range.
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RetiredWeasel
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Re: What airlines fitted 727s with INS?

Fri Apr 21, 2017 4:58 pm

longhauler wrote:
RotateAero wrote:
Continental Micronesia (to the best of my failing memory) did not have them installed either.

Do you know what they did use?
As some of their legs were beyond VOR/NDB range.


I jumpseated on Air Mike out of Guam several times in the early/mid '90s time frame. They had dual Omega's just as we did (NW) although it was a different model. Can't recall their model.
 
BravoOne
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Re: What airlines fitted 727s with INS?

Sat Apr 22, 2017 9:20 pm

RetiredWeasel wrote:
longhauler wrote:
RotateAero wrote:
Continental Micronesia (to the best of my failing memory) did not have them installed either.

Do you know what they did use?
As some of their legs were beyond VOR/NDB range.


I jumpseated on Air Mike out of Guam several times in the early/mid '90s time frame. They had dual Omega's just as we did (NW) although it was a different model. Can't recall their model.


Probably the same as they had in their DC10's after pairing down on the Collins INS that both CAL & WAL used. A pretty goodbox with some real issues regarding Collins backing up the product.

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