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Old 2nd Dec 2012, 08:38   #1 (permalink)
 
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RVSM contingency procedures

Hello,

Somebody could remind me the RVSM contingency procedures in case of decompresion and a rapid descent is required in Europe, US and Africa? Was going through the Jepp manual for those regions but nothing is specified. China, Middle East and Pacific region have a specific procedure to vacate the airway.

Thanks a lot
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Old 2nd Dec 2012, 09:26   #2 (permalink)

 
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Aircraft requiring rapid/emergency descent or diversion within RVSM airspace (except China/ DPRK) should leave the assigned route by turning at least 45 right or left, and acquire a track offset, which is the mid-point from the adjacent parallel track for all regions except Middle East and Oceanic regions. The offset for the Middle East region is 25 NM, while the offset for Oceanic regions is 15 NM. The initial direction of the turn will be determined by the relative position of other aircraft, adjacent airways and terrain. When an aircraft is able to maintain its assigned level and has deviated by 10 NM from the original track centreline, then climb or descend to a level 500 FT different from the normally assigned by ATC. When an aircraft is unable to maintain its ATC assigned level, the rate of descent should be minimized whenever possible and the subsequently selected level flight should differ by 500 FT from those normally assigned by ATC. If an aircraft requires to divert across the flow of adjacent traffic, it should expedite climb above or descent below levels where the majority of aircraft operate (e.g. to a level above FL 410 or below FL 290) and then maintain a level which differs by 500 FT from those normally assigned by ATC. However, if the Commander/PIC is unable or unwilling to climb above FL 410 or descent below FL 290, the aircraft should be flown at a level 500 FT above or below levels normally assigned until a new ATC clearance is obtained. China/DPRK RVSM. Aircraft requiring rapid/emergency descent or diversion within China/DPRK RVSM airspace should leave the assigned airway by turning 30 RIGHT and intercept a 5 NM offset from the airway centerline, then turn left to track parallel the original route, then climb or descend to the new level, and then return to the original route (when appropriate). When returning to the original route, be aware of conflicting traffic on that airway.

Weather Deviation Procedures Altitude deviation due to severe turbulence or Mountain Wave Activity (WMA). When an aircraft experiences severe turbulence and/or mountain wave activity, which results in an altitude deviation of approximately 200 FT or greater, the pilot shall immediately notify ATC and state "Unable RVSM due turbulence / mountain wave activity". If not immediately issued by the controller, request vectors or heading away from traffic at adjacent flight levels. Report the location and magnitude of the turbulence or MWA to ATC as soon as practical. Track Deviation for Weather. If a track deviation for weather is required and an ATC clearance cannot be obtained the following procedures shall be followed: 1. if possible deviate away from an organised track system. Broadcast intentions on 121.5 MHz and the air to air frequency 123.45 MHz. All available exterior lights should be selected on and the TCAS monitored for conflicting traffic 2. if the deviation is less than 10 NM, the aircraft should remain at the level allocated by ATC 3. if the deviation is greater than 10 NM, when the aircraft is 10 NM from track, initiate a level change based on the following criteria: Route Centre Line Track Deviations > 10 NM Level Change EAST 000-179 magnetic LEFT RIGHT DESCEND 300 FT CLIMB 300 FT WEST 180-359 magnetic LEFT RIGHT CLIMB 300 FT DESCEND 300 FT

When returning to track, be established at the previously assigned level when the aircraft is within approximately 10 NM of the centre line.

Reporting of Deviation from Cleared Flight Level If a flight deviates by more than 300 FT
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Old 2nd Dec 2012, 09:42   #3 (permalink)
 
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Quote:
Originally Posted by nitpicker330 View Post


Track Deviation for Weather. If a track deviation for weather is required and an ATC clearance cannot be obtained the following procedures shall be followed: 1. if possible deviate away from an organised track system. Broadcast intentions on 121.5 MHz and the air to air frequency 123.45 MHz. All available exterior lights should be selected on and the TCAS monitored for conflicting traffic 2. if the deviation is less than 10 NM, the aircraft should remain at the level allocated by ATC 3. if the deviation is greater than 10 NM, when the aircraft is 10 NM from track, initiate a level change based on the following criteria: Route Centre Line Track Deviations > 10 NM Level Change EAST 000-179 magnetic LEFT RIGHT DESCEND 300 FT CLIMB 300 FT WEST 180-359 magnetic LEFT RIGHT CLIMB 300 FT DESCEND 300 FT

When returning to track, be established at the previously assigned level when the aircraft is within approximately 10 NM of the centre line.

Reporting of Deviation from Cleared Flight Level If a flight deviates by more than 300 FT
Could anyone tell me why the 300 foot change in altitude instead of 500 feet. Is it in case of another aircraft on a contingency procedure?
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Old 2nd Dec 2012, 10:15   #4 (permalink)
 
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That would be my guess. You should still have 400ft separation if the altimeters in both airplanes are factory fresh.
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Old 3rd Dec 2012, 04:40   #5 (permalink)
 
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I would say that within 300 ft you are still occuptying the assigned FL, so you are actually amintaining it, only at its "limit"
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Old 3rd Dec 2012, 09:46   #6 (permalink)
 
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Quote:
I would say that within 300 ft you are still occuptying the assigned FL
Please tell me what airspace you operate in..... So I can avoid it!
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Old 3rd Dec 2012, 10:34   #7 (permalink)
 
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If I am flying at FL 310 and my altimeter indicates 31040 ft, am I still at FL340?
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Old 3rd Dec 2012, 16:31   #8 (permalink)
 
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RVSM contingency procedures

In RVSM space the altimeters have an allowable margin of upto
200 ft from the allotted FL. Any non standard deviation from the FL would have to be more than 200 ft. A 300 ft deviation from the assigned FL therefore can produce an aggregate of 500 ft which would consequently ensure a minimum separation of 500 ft from the reciprocal.
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Old 3rd Dec 2012, 16:45   #9 (permalink)
 
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Isn't the 200 ft limitation a limitation between both altimeters, rather than a limit deviation from the nominal FL? Anyway, the weather avoidance contingency procedure is telling you to climb or descend 300 ft.

My question is: when climbing from, say, FL 310 to FL 320? where does FL 310 end and where does FL 320 begin?

Last edited by Microburst2002; 3rd Dec 2012 at 16:47.
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Old 3rd Dec 2012, 17:21   #10 (permalink)
 
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Well in FAA land, our ATP standards require you to be able to hold altitude within 50ft, so I assume FL310 stops at 31,050ft, and FL311 begins at 31,051ft.
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Old 4th Dec 2012, 04:05   #11 (permalink)
 
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Any ATCO around here that can clarify where are the limits?

My notion is +-300 ft. I mean, you are clear of FL 300 climbing only once you have passed 30,300 ft.

I can't remember where I read it. Maybe an ICAO annex
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Old 4th Dec 2012, 04:43   #12 (permalink)
 
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For FAA purposes, the Mode C readout is considered to be valid if it is within 200ft of the pilot's reported altitude.
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Old 4th Dec 2012, 07:03   #13 (permalink)
 
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All right

But I am referring to the limits of the level, not the altimeter tolerance or xpndr tolerance.

I feel lazy and I know it could take me hours to find the text where I read that an airplane is considered to be occupying a level anytime it is within 300 ft of it.

As a matter of fact when they instruct me to advise clear of a level, or to expedite through a level, I always wait until I have passed 300 ft after it to report clear or to resume normal rate.

Any one out there can confirm this 300 ft rule?
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Old 4th Dec 2012, 08:27   #14 (permalink)
 
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According to the following report on level busts by Eurocontrol it would appear that the 300ft level bust gate is not that strictly defined. Page 2 refers.

But 300ft is what our company uses.

http://citeseerx.ist.psu.edu/viewdoc...=rep1&type=pdf

And it would appear that ATC in the UK at least regard you having reached a FL when they get 3 successive mode C readouts within 200ft of that cleared level. MATS 10.3.1 (CAP 493). So I guess given that our modern altimeters won't let us set 50ft increments then the level bust of 300ft is the next one up from 200ft.

Last edited by MCDU2; 4th Dec 2012 at 10:19.
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Old 4th Dec 2012, 10:22   #15 (permalink)
 
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Now we are getting somewhere...

Quote:
1.1.3.
Level Bust Definition
A level bust is defined as a situation in which a flight does not capture or does not maintain the Flight Level or Altitude assigned to it by ATC with a deviation of more than 300ft.
MCDU2: note the "more than" 300 ft. At 300 ft you are still OK...

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PD I hate that bloody emoticon...

Last edited by Microburst2002; 4th Dec 2012 at 10:24.
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Old 4th Dec 2012, 10:37   #16 (permalink)
 
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The wx avoidance contingency procedure when beyond 10 nm from the awy centerline looks complicated, but it is something like:

All airplanes flying north of wx descend 300 ft, westboud or eastbound. All airplanes flying to the south, climb 300 ft.

In this manner, two airplanes in opposite direction will maintain 1000 ft separation. One airplane deviating and another clear of wx along its own nearby route in opposite crossing directions will be 1300 or 700 ft separated from you. And it will be 300 ft separated from a traffic at the same level in a converging route in same direction, or opposite at a non std level. Better than nothing...

And all the time you are considered to be at your original FL.

Again, I hate those smileys...
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Old 7th Dec 2012, 04:51   #17 (permalink)
 
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300 ft altitude change

Think of airplanes coming the other direction on a adjacent track at the same altitude, or at neighboring altitudes. If you both have to deviate toword each other. The guy deviating to the north of his track will descend 300 feet, the plane deviationg south will climb 300 feet, giving you up to 400 feet between you.
If you both changed kept the same altitude, you could collide. If you both changed altitudes by 500 feet, then you risk collision from adjacent tracks and adjacent altitudes doing the same and all ending up in the same place.
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Old 7th Dec 2012, 13:43   #18 (permalink)
 
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Awesome....thanks.
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Old 5th Jun 2013, 08:05   #19 (permalink)
 
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300 ft altitude change
Think of airplanes coming the other direction on a adjacent track at the same altitude, or at neighboring altitudes. If you both have to deviate toword each other. The guy deviating to the north of his track will descend 300 feet, the plane deviationg south will climb 300 feet, giving you up to 400 feet between you.


Which airspace is this?
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Old 5th Jun 2013, 08:48   #20 (permalink)
 
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Technical Stuff about RVSM

RVSM is 1,000 ft (300 m) vertical separation of aircraft at higher altitudes typically above FL290. The controlling authority of each FIR/UIR in which RVSM is approved will determine the lower and upper limits for RVSM flight. Normally, the upper limit is either FL390 or FL410.

All aircraft intending to operate in RVSM airspace must have specific approval for such operations. The approval will encompass the aircraft equipment, aircraft maintenance and airworthiness procedures, and flight-crew training procedure.

There are a number of requirements in terms of equipment and capabilities needed for flight in RVSM Airspace. Of significance are the accuracy requirements.

Assigned Altitude Deviation. The difference between the transponder Mode C altitude and the assigned altitude or flight level. This type of error will be identified by ATC and is most likely to occur if an incorrect altimeter setting is used, or the aircraft is flying at an incorrect flight level.

Altimeter System Error. The difference between the altitude indicated by the altimeter display (assuming a correct altimeter barometric setting) and the pressure altitude corresponding to the undisturbed ambient pressure. This type of error is caused by the cumulative effects of components within the altimeter system causing an aircraft to fly a pressure altitude different to that displayed on the altimeter. This type of error would normally only be identified by measuring actual aircraft height by external means.

Total Vertical Error. Vertical geometric difference between the actual pressure altitude flown by an aircraft and its assigned pressure altitude (flight level). Total vertical error is the sum of all errors, whether pilot or equipment, that cause an aircraft to fly at a pressure altitude different to that assigned. Depending on the cause, ATC may be capable of identifying the error

The following are the limits for each of these.

AAD equal to or greater than 300 ft
ASE equal to or greater than 245 ft
TVE equal to or greater than 300 ft.

Note that the maximum acceptable is 300ft.
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