Viscount Routes question...

[Macs]

Hi,
I was wondering if anybody knew what routes were flown by Viscounts in the Central America-North America region. I know that airlines like TACA used to fly Viscounts in routes from various Central American countries to destinations like New Orleans and possibly Miami. I've heard a popular one had a stop in Merida, Mexico, but am wondering how they managed to cross the Gulf of Mexico from there without INS or GPS? and what defined those routes? Did they follow the coast? I mean, a VOR can only do about 190 nm, and that is at a very high altitude; and I doubt aeronautical regulations would let airliner traffic go by dead reckoning also (risk of collision)... Also, did those planes have a limit of 17,000 ft? Just curious, as I'd like to try one myself
regards,
Macs

[DispatchDragon]

Macs
I think I can field this one for you as we operate to MMUN/MMCZ on the same routes as you state evey winter obo Apple Tours - even with the
MD80 there is a 20 minute "dead spot" where you lose the Leeville (LEV)
VOR before aquiring the Merida VOR - the routing is as follows
LEV- A626 BUFFI SWORD CEDRO (which is about where you aquire the MID VOR and CUN VOR) depepnding on routing after CEDRO UJ57 takes you to MMUN A626 takes you to the CZM VOR - for routings to MMID
LEV-A770 DOLPH KEHLI ALARD (where you will aquire the MID VOR) AVASA MEDIR MESNA MMID

The section from DOLPH to KEHLI is DR even today unless flying GPS
on A626 its BUFFI to SWORD .

Strangley enough though you can talk to Houston Oceanic ARTCC almost all the way to KEHLI on VHF - there is also ARINC on (NewYork Radio) on 130.7 All the way across After KEHLI and SWORD you can normally talk to Merida and in some cases Cancun on VHF.

These routes both predate GPS and Omega (prior to its dissolution)
Before GPS Aircraft operating these routes preferred to have Omega
or LORAN C however there is no requirment for any over water nav euqipment and many airlines operate the 20 minute dead spot in DR
(Truth to tell many times GPS will drop into DR or Ghost mode when
they lose the LEV or HRV Vors)

The most common method of navigating the dead spot is IFC (I Follow Contrails) where you are tracking the contrail of the aircraft ahead of you



Have fun flying the Viscount down there

Leif

[Macs]

Macs
I think I can field this one for you as we operate to MMUN/MMCZ on the same routes as you state evey winter obo Apple Tours - even with the
MD80 there is a 20 minute "dead spot" where you lose the Leeville (LEV)
VOR before aquiring the Merida VOR - the routing is as follows
LEV- A626 BUFFI SWORD CEDRO (which is about where you aquire the MID VOR and CUN VOR) depepnding on routing after CEDRO UJ57 takes you to MMUN A626 takes you to the CZM VOR - for routings to MMID
LEV-A770 DOLPH KEHLI ALARD (where you will aquire the MID VOR) AVASA MEDIR MESNA MMID

The section from DOLPH to KEHLI is DR even today unless flying GPS
on A626 its BUFFI to SWORD .

Strangley enough though you can talk to Houston Oceanic ARTCC almost all the way to KEHLI on VHF - there is also ARINC on (NewYork Radio) on 130.7 All the way across After KEHLI and SWORD you can normally talk to Merida and in some cases Cancun on VHF.

These routes both predate GPS and Omega (prior to its dissolution)
Before GPS Aircraft operating these routes preferred to have Omega
or LORAN C however there is no requirment for any over water nav euqipment and many airlines operate the 20 minute dead spot in DR
(Truth to tell many times GPS will drop into DR or Ghost mode when
they lose the LEV or HRV Vors)

The most common method of navigating the dead spot is IFC (I Follow Contrails) where you are tracking the contrail of the aircraft ahead of you



Have fun flying the Viscount down there

Leif

Leif,
Many thanks for your help, this is trully interestng! 20 minutes of DR and IFC (sweet) is a long time! Gotta try it! :dance: I can see where communications play an important role there (VHF, HF and so on..). You know, I can see also where the doppler radio navigation system would have worked great here, as the one fitted to Tridents and most Russian airliners (NAS-1). Again, thanks for the information.

regards,
Macs

P.S.: Just out of curiosity, what airlines does Apple Tours use for this route?

[DispatchDragon]

Macs

Depending on what departure Airport

USA3000 A320
Ryan International A320/MD80
Allegiant (thats us) MD83

Im here for all your Latin American/Caribeean Needs

Leif

[Macs]

Macs

Depending on what departure Airport

USA3000 A320
Ryan International A320/MD80
Allegiant (thats us) MD83

Im here for all your Latin American/Caribeean Needs

Leif

Cool stuff. Thanks again Leif.
regards,
Macs

[Macs]

Macs

Depending on what departure Airport

USA3000 A320
Ryan International A320/MD80
Allegiant (thats us) MD83

Im here for all your Latin American/Caribeean Needs

Leif

Leif,
Here's a compilation of the flight. One of the most fun I've had in a while! Thanks for the guideance



regards,

Macs

[cstorey]

Before INS, dead reckoning was the primary way of planning, assisted by Omega and Loran ( although these were going out of fashion by the 1960s) and on long overwater routes, ( and in some other areas such as the Sahara) astral navigation was used to check the DR, with a bubble sextant sighted through a small dome . it would be interesting to know from Tonks whether these are still fitted on the VC 10 , or whether they have been blanked off

[DispatchDragon]

and on long overwater routes, ( and in some other areas such as the Sahara) astral navigation was used to check the DR, with a bubble sextant sighted through a small dome . it would be interesting to know from Tonks whether these are still fitted on the VC 10 , or whether they have been blanked off

Britannia used Perismatic Sextants on Far Eastern Flights on the Britannia 102s until their demise and IAS frequently carried freelance Navs on their 300s - Which is where I learnt to use one and the magic blue book


Leif