Questions tagged [dme]

DME (Distance Measuring Equipment) is, as the name suggests, a system for measuring the slant distance between a suitably-equipped aircraft and a ground-based transponder station; DME stations are often colocated with VOR or ILS installations.

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How does increasing the rate of pulse pairs in DME 'search' mode help?

From How does an airborne DME unit differentiate itself? The higher rate in SEARCH [150 PP/S] gives it more opportunity to detect the replies as it has no knowledge of range in search and thus has to ...
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3 votes
1 answer
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How do you calculate the deviation from an RNAV waypoint radial?

As a clarification at the beginning: I'm talking about non-GPS, pure VOR-DME based RNAV devices here. On RNAV devices that use just the selected VOR-DME, not GPS, the phantom radio station is set up ...
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5 votes
1 answer
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What does a DME indicator do in HOLD or RNAV mode?

I found this DME indicator on the Cessna 210. Its mode switch has four positions - NAV1, NAV2, RNAV and HOLD. NAV1 and 2 are clear - it uses the NAV1 and 2 freq respectively. I'm wondering what the ...
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Can an IFR civilian aircraft use a TACAN for DME distances? [duplicate]

Flying the KRDR LOC RWY 35 approach. How do I get my DME distance to HONNE or CANLI? can we pick up DME distance from a TACAN? Just used GPS Overlay but can we get distance from the TACAN?
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9 votes
2 answers
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Are there two navaids on the same frequency close enough to be confused?

Several RTCA DO standards require checks for bad navaid tuning including, "In lieu of using ground-based navigation aid designated operational coverage (DOC), the system should provide, checks ...
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11 votes
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How can the A320 receive 3 DME signals if it has only 2 DME receivers?

How can the A320 receive simultaneously 3 DME signals (VOR1 + VOR2 + ILS) if it has only 2 DME receivers (and antennas)? Does it multiplex them in some way? If yes, does it mean if one DME receiver ...
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1 vote
1 answer
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How does a VOR or a VORDME affect the coding decision between CF or IF-TF respectively?

I was reading of the following case in ARINC 424-17 spec. Unfortunately the image is copyrighted and I can't paste it here, so here is a low(er) quality image of mine replicating the situation: The ...
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1 vote
1 answer
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How is DME station ident coded in ARINC 429?

I understand that labels 242,244, 246, 247 are set for DME Station Id or DME Station Ident. they are marked as discrete. How should I convert the station code from alphabet to these 'discretes'? The ...
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1 vote
3 answers
337 views

What button do I push on the instrument panel to activate DME in VOR navigation? [closed]

For some strange reason I cannot seem to find any information about what button to push on the instrument panel to active the DME. There is plenty of information about how DME works with ...
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2 votes
2 answers
260 views

What does it mean to "lock on" to a DME ground station?

I was just reading about the working of the DME the other day and then I read a para which said: The aircraft interrogator "locks on" to the DME ground station once it recognizes a particular ...
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Why don't aircraft have DME that can automatically convert the slant range to ground range?

Knowing that $a^2 = b^2 + c^2$ where $a = \text{slant range},\ b= \text{ground range},\ c = \text{height}$. Why can't the DME equipment which calculates the slant range then just convert it to the ...
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8 votes
1 answer
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How does an airborne DME unit differentiate itself?

The FAA's IFR handbook glosses over a keypoint: The aircraft DME transmits interrogating radio frequency (RF) pulses, which are received by the DME antenna at the ground facility. The signal ...
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3 answers
2k views

How can I know DME distance? [closed]

When I fly 12000ft, how can I know a distance from DME station? Is there any formula to know or measure distance from DEM?
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What is the available range for DME, and why do we need EFC?

How far from the station can a DME signal be picked up, and why do we need EFC?
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1 answer
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How can I triangulate a position using two DMEs?

What is the formula for determining an aircraft's position (latitude, longitude) using barometric altitude and the ranges to two DMEs?
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1 answer
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Do UAVs use ground-based navaids?

When I Googled it seems it is not common to use Vortac like systems from UAVs as a backup to GNSS outages, like in manned aircraft. And also I haven't seen any equipment designed for just UAV ...
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4 votes
1 answer
924 views

Are there benefits in training instrument students how to fly a DME arc?

With more instrument approach procedures being designed for RNAV/GPS equipped aircraft, and considering the high level of radar coverage currently available, is there a need to spend much valuable ...
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