Author Topic: ATIS "Decoder" ?  (Read 23741 times)

Offline piper cub

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ATIS "Decoder" ?
« on: August 21, 2008, 03:51:04 PM »
Greetings from new Danish member!

I'm in the process of an international VHF study. The CD from the flying club contain several ATIS audio samples, but the computerized voice sometimes speaks fast and and with bad sound quality, which makes understanding of some phrases hard.

So, do any of you guys know of a collection written ATIS samples, where I can look for the "mysterious" phrases - or are you aware of an ATIS "decoder" translating the audio intro writing in for instance Words?

best regards


Offline Canadian eh

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Re: ATIS "Decoder" ?
« Reply #1 on: August 21, 2008, 06:15:43 PM »
i'm not aware of any "progarm" that will convert a weather sequince to writing or vs versa but i could probably dig up a list of all the aberviations (BR mist and so on), the rules for combining numbers, diff between overcast right through to sky clear and if i dig real deep some of the weird stuff you might see like when they release balloon. or i'm sure you could post whatever "mysterious" phrases you have and most of us would be willing to tell you what they mean

Offline Chananya Freedman

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Re: ATIS "Decoder" ?
« Reply #2 on: August 21, 2008, 06:31:44 PM »
You can also send me a PM by clicking on my name and clicking on my computer icon and I might be able to help you and you don't have to ask too many questions here.  If not, I can direct you to the correct people.  Glad I could be of assistance.


Offline cessna157

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Re: ATIS "Decoder" ?
« Reply #3 on: August 21, 2008, 10:00:20 PM »
ATIS is just a reading of the current hourly METAR.  Just search the inter-web for metar decoders and you'll have your answer.

Offline Fryy/Avocadoflight

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Re: ATIS "Decoder" ?
« Reply #4 on: August 21, 2008, 10:32:24 PM »
hopefully this link will help you out.

Offline KSYR-pjr

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Re: ATIS "Decoder" ?
« Reply #5 on: August 22, 2008, 01:07:23 AM »
ATIS is just a reading of the current hourly METAR. 

Plus local NOTAMs, runway and approaches in use, bird activity, hazardous weather information, and even an occasional PIREP.   Not exactly sure, though, where in the ATIS the OP is having trouble deciphering it.

Offline piper cub

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Re: ATIS "Decoder" ?
« Reply #6 on: August 22, 2008, 02:11:08 AM »
Thanks guys

ATIS is not just a METAR or a TAF. It also contains a lot of runway information like approach/departure data, surface and breaking conditions. It is especially the runway info causing me trouble.


Offline KSYR-pjr

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Re: ATIS "Decoder" ?
« Reply #7 on: August 22, 2008, 10:43:03 AM »
It is especially the runway info causing me trouble.

RVR is mentioned on the ATIS when visibility is way down due to precipitation or fog, normally when visibility drops below one mile.  Is that one of the runway components you are questioning? 

At many airports in the US runway visual range, or RVR, is measured in feet and is a criterion used to determine whether an instrument approach can be started (part 121 - scheduled air carrier, and part 135 - air taxi, freight) or a landing can be made.   

Instrument charts in the minimums table at the bottom of the chart give visibility in the RVR value, as seen here:

The 18 and the 24 I highlighted are actually 1800 (feet) and 2400 (feet) and that is the minimum visibility, or RVR value, a pilot must observe in determining whether the approach can be started (again, all operations but part 91) or, once on the approach, a landing can be made.

Therefore, on a low visibility day you might hear on the ATIS among other things, ".... RVR 1800, touchdown 2500, rollout 2500."       This translates to runway visual range of 1,800 feet, runway visual range at the touchdown point of the runway as 2,500 feet, and runway visual range once rolling out on the runway of 2,500 feet.

Offline piper cub

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Re: ATIS "Decoder" ?
« Reply #8 on: August 23, 2008, 01:12:17 PM »
Very useful information indeed, thank you Peter!

Only, what does the A,B,C and  D in the Horizontal bar stand for?

Maybe similar to TDZ (Touch Down Zone), MID and END), which I see in some tests. Also in Europe lengths on the runway are measured in meters.


Offline KSYR-pjr

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Re: ATIS "Decoder" ?
« Reply #9 on: August 23, 2008, 01:23:15 PM »
Only, what does the A,B,C and  D in the Horizontal bar stand for?

That is the category of aircraft.  Every certified aircraft is categorized based on approach speed with the theory being "the faster the aircraft's approach speed, the wider the turning arc needed and hence the higher the approach minimums."

From the FAA's Instrument Procedures Handbook (which is in PDF format and why I am including the text here):


Two other critical performance factors that should be
considered during the planning phase of an instrument
approach are aircraft approach category and planned
approach speed. According to the December 26, 2002
amendment of Part 97.3 (b), aircraft approach cate-
gory means a grouping of aircraft based on reference
landing speed (VREF), if specified, or if VREF is not
specified, 1.3 VS0 (the stalling speed or minimum
steady flight speed in the landing configuration) at the
maximum certificated landing weight. VREF refers to
the speed used in establishing the approved landing dis-
tance under the airworthiness regulations constituting
the type certification basis of the airplane, regardless of
whether that speed for a particular airplane is 1.3 VSO,
1.23 VSR, or some higher speed required for airplane
controllability such as when operating with a failed
engine. The categories are as follows:

• Category A: Speed less than 91 knots.

• Category B: Speed 91 knots or more but less than
121 knots.

• Category C: Speed 121 knots or more but less
than 141 knots.

• Category D: Speed 141 knots or more but less
than 166 knots.

• Category E: Speed 166 knots or more.

• NOTE: Helicopter pilots may use the Category A
line of minimums provided the helicopter is oper-
ated at Category A airspeeds.

An airplane is certified in only one approach category, and
although a faster approach may require higher category
minimums to be used, an airplane cannot be flown to the
minimums of a slower approach category. The certified
approach category is permanent, and independent of the
changing conditions of day-to-day operations. From a
TERPS viewpoint, the importance of a pilot not operating
an airplane at a category line of minimums lower than the
airplane is certified for is primarily the margin of protec-
tion provided for containment of the airplane within the
procedure design for a slower airplane.  This includes
height loss at the decision altitude, missed approach climb
surface, and turn containment in the missed approach at
the higher category speeds. Pilots are responsible for
determining if a higher approach category applies. If a
faster approach speed is used that places the aircraft in a
higher approach category, the minimums for the appropri-
ate higher category must be used. Emergency returns at
weights in excess of maximum certificated landing
weight, approaches made with inoperative flaps, and
approaches made in icing conditions for some airplanes
are examples of situations that can necessitate the use of a
higher approach category minima.

Circling approaches conducted at faster-than-normal
straight-in approach speeds also require a pilot to consider
the larger circling approach area, since published circling
minimums provide obstacle clearance only within the
appropriate area of protection, and is based on the
approach category speed. [Figure 5-3] The circling
approach area is the obstacle clearance area for airplanes
maneuvering to land on a runway that does not meet the
criteria for a straight-in approach. The size of the circling
area varies with the approach category of the airplane, as
shown in Figure 5-3. A minimum of 300 feet of obstacle
clearance is provided in the circling segment. Pilots
should remain at or above the circling altitude until the
airplane is continuously in a position from which a
descent to a landing on the intended runway can be made
at a normal rate of descent and using normal maneuvers.
Since an approach category can make a difference in the
approach and weather minimums and, in some cases, pro-
hibit flight crews from initiating an approach, the
approach speed should be calculated and the effects on the
approach determined and briefed in the preflight planning
phase, as well as reviewed prior to  commencing an

Offline piper cub

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Re: ATIS "Decoder" ?
« Reply #10 on: August 23, 2008, 01:26:32 PM »
Also, I've realized transcripts of ATIS announcements would be very useful for learning i.e having a checking possibility when the computerized voice is to quick and unclear for my understanding. I'll then go through the trancripst and find the unclear phrases. Do not nessesarily need the voice. PDF's anyone?


Offline Robin Rebhan

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Re: ATIS "Decoder" ?
« Reply #11 on: August 23, 2008, 04:02:54 PM »
Sporty's has an "ATIS wheel" they sell.
Not sure if this is what you are looking for. You can give them a call.

    Also, for those interested I can work out renting a room out for international students here in my home Albany, NY USA for a nominal fee. Full time flight school, Richmor Aviation ( accepts International students )  20 minute drive and also Schenectady Community College has 2 year aviation program which also uses Richmor Aviation for aircraft, both would require student to have rental car. I have flight simulator, high speed computer access, sporty's Private pilot and IFR course videos. In radio range of class C and D airports as well as non-tower airports.
     I think it would be a fun thing to do. Nothing like jumping right into the English language.
    ( Mrs. Pilot just walked by, and she is on board with the idea ).

     Robin Rebhan
     Albany, NY
« Last Edit: August 25, 2008, 07:23:24 PM by Robin Rebhan »