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View Full Version : When is UHF required?


Busdriver91
11-20-2018, 11:56 AM
I work for a 135 operator and the airplane does not have a UHF radio. We have ops spec which allows the airplane to fly with single-long range in the western Atlantic. I am being told by people in our training department that we are not allowed to fly the Atlantic Routes between the Bahamas and Wilmington because we don’t have a UHF radio. Is this correct?
Regs specifically state UHF is required beyond line of site communication, but that doesn’t really answer my question.


tomgoodman
11-20-2018, 12:18 PM
I work for a 135 operator and the airplane does not have a UHF radio. We have ops spec which allows the airplane to fly with single-long range in the western Atlantic. I am being told by people in our training department that we are not allowed to fly the Atlantic Routes between the Bahamas and Wilmington because we don’t have a UHF radio. Is this correct?
Regs specifically state UHF is required beyond line of site communication, but that doesn’t really answer my question.

Don’t you mean HF? :confused:

galaxy flyer
11-20-2018, 12:24 PM
He was told, “ya need uh HF radio, dude.”

GF


UAL T38 Phlyer
11-20-2018, 12:50 PM
Busdriver:

UHF is used almost exclusively by military.
225-399.95 MHz

Typical ATC VHF:
118.0-136.95MHz

HF is the lowest frequency (and therefore, longest range)
2.1-28.0 MHz
Usually written as
2100-28,000 KHz.

Busdriver91
11-20-2018, 01:22 PM
Yes, now that I have been thoroughly schooled in the use of different types of radios that I have never used, back to my original question (however insert HF instead of UHF).

TiredSoul
11-20-2018, 01:52 PM
I didn’t read all 114 pages figuring I’d leave you something to do:

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_91-70B.pdf

UAL T38 Phlyer
11-20-2018, 03:44 PM
The more common VHF ATC radios have a range of about 120-200 miles, depending on a number of factors.

Overwater routes that exceed or are near these limits will require HF. HF can sometimes go halfway around the world...very dependent on frequency, time of day, the ionosphere, and atmospheric/solar interference.

For airlines, we are required “LDOC:” Long Distance Operational Control. This can be met by ACARS and SATCOM, with HF as a backup. LDOC is also used for ATC coordination on long haul routes, such as the Atlantic or Pacific.

I’m not sure in your case if that is for Operational Control, ATC, or both.

In days past, it was done by dual HFs. Your company might get by with that, or an HF and a SATCOM.

galaxy flyer
11-20-2018, 04:13 PM
I don’t think you need HF between Carolina Beach and the Florida airports, VHF has coverage. Further east and over BDA, you’ll need HF. AR3 is only 200 nautical off JAX, which st jet levels has VHF coverage.

GF

zondaracer
11-21-2018, 10:07 AM
A good rule of thumb for VHF range is square root of your flight level, multiplied by 12.

If you are at 10000 feet, you'll have about 120NM of range. FL300 and you'll have close to 208NM of range.

UAL T38 Phlyer
11-21-2018, 10:27 AM
A good rule of thumb for VHF range is square root of your flight level, multiplied by 12.

If you are at 10000 feet, you'll have about 120NM of range. FL300 and you'll have close to 208NM of range.

Good one! Never heard that before.

zondaracer
11-21-2018, 10:31 AM
Good one! Never heard that before.

Haha yeah it’s one of the EASA ATPL test questions.

galaxy flyer
11-21-2018, 11:02 AM
To be pedantic, it’s the square root of the altitude of each antenna times 1.23. Square root of 10,000 is 100 x 12 equals 1200 nm.

GF

zondaracer
11-21-2018, 11:26 AM
To be pedantic, it’s the square root of the altitude of each antenna times 1.23. Square root of 10,000 is 100 x 12 equals 1200 nm.

GF

Don’t you mean 100 x 1.23 which is 123? 😆

Elevation
11-22-2018, 09:34 AM
The guy that gave you AC91-70 was actually being pretty helpful. HF is required in oceanic airspace but different flight information regions have other, different requirements. So it's important to read-up since applying one rule of thumb to the wrong part of the world can sometimes get you in trouble.

A good way to start familiarizing yourself with this stuff is looking at the Jeppesen, paper orienation charts. They are full of notes and useful nuggets of information.

EMAW
11-22-2018, 05:28 PM
No, the routes off the east coast or those across the gulf for that matter do not require HF. What you may have to do, depending on distance and altitude, is comply with non radar and or lost comms procedures as directed by the controller. I just dealt with that situation crossing the gulf below FL250.

Elevation
11-22-2018, 06:30 PM
Another thing to add is that “oceanic airspace” does not mean airspace over oceans. It means airspace in oceanic control areas (oceanic FIRs or OCAs within specific FIRs).

There are also specific routings through particular OCAs which do not require HF, like Blue Spruce routes, etc.

EMAW
05-06-2019, 03:39 AM
Another thing to add is that “oceanic airspace” does not mean airspace over oceans. It means airspace in oceanic control areas (oceanic FIRs or OCAs within specific FIRs).

There are also specific routings through particular OCAs which do not require HF, like Blue Spruce routes, etc.

This. The Atlantic Routes are not oceanic. And at higher altitudes the airspace is controlled by US ATC, even in the Islands. Just have to have a raft on board.



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