In some cases, your system may return an error code indicating how the slope range error is calculated. This error can have various reasons. g.The most extreme case of a “bank error” occurs when the plane continues to fly over the station; instead, the DME displays the aircraft’s height above the store (in nautical miles). Slant range error also affects ground speed, and the time to station is displayed when you are close to the aircraft.

 

 

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Dan Chitty 07/27/2015

DME displays distance in nautical miles, ground speed in knots and therefore time M to the station in minutes. Note, however, that ground speed and time to DME station are full only when flying directly or from a ground station. If you fly in different directions, you will see ground speed because it is erroneously low and the parking time is too long.

When you are away from a station, the ground speed must be accurate, but in fact, the time to the station may take longer to display from the station.

Another thing to keep in mind is the DME, which measures straight-line distance from an aircraft as a route to a ground station. This is often referred to as the slant distance and is slightly greater than the actual horizontal distance just because of the difference in height between the aircraft and the station. The most extreme case of “furnace tilt failure” occurs when the plane is flying directly over the station; instead, connected to zero, the DME reading shows the altitude of your aircraft above my station (in nautical miles).

For example, if the station is horizontal and you are flying at 9,000 feet, the DME will show 1,5 miles if you go straight through the station. If you are 2 nautical miles horizontally from the station, the DME will show 2.5 miles. At large distances from the station, the accounted slant range distortion is negligible.

Tilt error also affects ground speed, as well as the time to stop if you are near a certain station. The displayed DME ground speed drops below the actual ground speed as you unambiguously approach a station and then increases again so you can pass normally. The displayed DME time to station may not count down to zero in all directions, even if you hover over a station.

This Is How DME Works

Remote equipment (DME) includes both ground and airborne equipment. You can usually find DME devices with VOR or ILS / LOC. NAVAID loves VOR and the systems send navigation signals via VHF. However, other DMEs are transmitted via UHF. The FAA even aligned NAVAID VHF frequencies with UHF frequencies in conjunction with DME frequencies. Example

All VORs controlled This is 113.0, will use the actual DME frequency no matter where your VOR is. The FAA is removing NAVAID to ensure mixed frequencies are not blocking your receiver.

Radio DME is measured remotely by measuring the interval between the “request pulse” from the transmitter and then the “response pulse” from the AV receiver. It is as if the submarines made the best use of sonar signals that ricocheted off objects depicting the ocean floor.

The DME should be displayed in nautical miles and evaluated as a distance known as “slope distance”. Due to the way this large aircraft flies, slope distance measurements will always exceed expected distances.

For example, if an airplane is flying directly with a DME transmitter at 6,000 feet, the DME should show approximately 1 NM.

What is the typical DME tilt range for most flights? The rule of thumb for these is that if you are at least 1 mile from a station to travel every 1000 feet above sea level, the tilt range is virtually negligible Lelen.

Thus, if you were flying 5000 feet above the DME Depot (AGL) and were at least 5 nautical miles from the blast site, the DME reading is accurate.

how to calculate slant range error

The DME requires a line of sight between the plane and the train on the ground, and the terrain and distance above the horizon prevents the DME from functioning.

Ground DME transmitters are also designed for approximately 100 aircraft simultaneously. If too many aircraft are charging the device, more distant devices will not be able to amplify the DME signals on all of them.

GPS DME Vs. Conventional DME

Thanks to GPS, pilots use less and less of the original DME. When flying IFR with approved GPS, GPS distance can be used as a positive replacement for DME.

how to calculate slant range error

For example, if you are still flying ILS and the DME for the FAF is 5 different miles from the LOC and antenna, you are currently 2 miles from the fix, your DME GPS will buy you 2 miles from a successful FAF. …

If you really want GPS DME to match traditional DME for ILS approach, you can enter “Direct IXXX” to use distance ii corresponding to your contact with the card.

However, we do not recommend doing this, as you can draw a straight line on the street map without giving any idea of ​​which path to take to the trail.

Don’t Forget About The HOLD Function!

Distance calculation The distance formula, Distance Implies Rate * Time, is used by the DME receiver to calculate its final distance from the DME ground location. The calculations have always used the speed of the radio signal, that is, the bleaching speed (approximately 300,000,000 m / s or 186,000 m / s).

Have you ever traveled with an ILS that references distance records from the nearest VOR rather than leaving the LOC? For aircraft fully equipped with a DME radio, you should know what the “Hold” button is for. On an approach that registers DME from the nearest NAVAID, users must first tune their NAV radios to the DME source, essentially press “HOLD”, and then match the navigation data from the frequency. Remember advice like the one we mentioned that DME UHF wavelengths are always individually tied to VHF frequencies? If you “HOLD” the DME frequency of the NAVAID dial, you will lock the DME speed to switch to the new NAVAID depending on your emphasis.

Drive the ILS at Vor Falls (KTVF) to Runway 31. Approach is determined by TVF VOR with DME. Since you have an arc on the localizer course,you will probably be referring to DME TVF. When people arrive, switch to I-HYZ LOC on 110.5. But first you need to press “HOLD”. This will block TVF-DME books on your DME radio as this is definitely distance information for the particular approach being used. If you are not at everything, the same principle applies. First you need to set TVF, press “HOLD” with your finger, then switch to the I-HYZ LOC frequency.

When you’re done with the acquisition, remember to redefine the DME frequency so that future approaches do not refer to incorrect range information.

Which Devices Are Equipped With DME Radios?

You probably won’t find all these traditional dme radios on canister training planes. Instead, the most common aircraft are equipped with multiple GPS receivers.

However, people will still find DME stereos throughout the industry. Most transport categories offer aircraft DME, and a few former IFR GA certified aircraft also have aircraft DME. In fact, FAR 91.205 (d) (2) includes all aircraft certified to fly IFR above FL 240 and “desirably equipped with an approved DME or RNAV system”.

Is your aircraft equipped with a DME? Does he only have Tell GPS devices? in the comments below.

 

 

MSL, simply subtract the field size from your current altitude, in which case multiply that number by 3. After you complete the calculations, you will know that your location should begin to descend 45.5 miles from the airport. Remove the last two zeros from this number, and it becomes 25.5 m. Miles.