Baro settings / when way below zero.
 

In most aircraft of airliner ilk of today, A320 ad nauseam . . there is the CADC but even this can or will not contain the inherent errors of very cold conditions.

Is there a universal formula for a set up of the baro altimeter - when it is very damn cold . . .?

"Hi temp to lo - look out below!"

If I understand the question, this is basic knowledge and it will/should be in your Part A (or perhaps C?). I can only assume I don't understand.................

Yes. It's in Jepps. There are apps too. Or you could run 4 times ISAD times your alt in 1000s above the aerodrome.

Be warned with any of these, they only work accurately in a uniform column of air, not inversions. Last time i used them it was minus 32 on ground, but minus 22 at 4000 feet, so be mindful of that.

So far only a consultation document, but here's the info from the CAA
http://www.caa.co.uk/docs/2261/20120...onDocument.pdf

From 8168: (the 1b table referenced is the same, just in feet)

http://i43.tinypic.com/acsg0w.jpg

EDIT: standard temp for the airport.. ISA°C= 15°-(airport elevation/500)

You are adjusting the altimeter QNH setting to compensate for colder than standard temps or am I missing something?

When operating in a colder than standard atmosphere the Honeywell FMS calculates the higher crossing altitudes with the Temp Comp feature. We leave the altimeter setting alone and add altitude accordingly to cross the fixes at a higher indicated altitude which equals the original crossing altitude adjusted for error. The FMS takes the guesswork out of it.

I would think that an inversion like that would make your temperature correction calculation to be on the conservative side so therefore, no worry.

Good point though. Do these corrections take into account a standard lapse rate or a uniform temperature in the column of air.

Thank you.
 

apologies to everybody and thanks everyone.

>>
How much must we add to the current alt, when OAT = -xx?

Jammed Stab

I think is has got to be OAT. "If OAT = -xxdeg then at y feet apply n feet to give altitude required, something like - "if at -35 deg if 1,000 needed then cross at 1900


Edited -ad nauseam . . reason for editing: because I am being silly and I cannot write.

The original question OP thing, should have read. "How much do we add onto the readout on the altimeter when the temp is very low like -35 or something degrees . . . ?

I looked at the CAA thing . . .I think they have got it too low (i.e., not enough), but what do I know . . ?

I was trying to follow the chart above, similair to the CAA one but I am suffering from (GIS) Glenfiddichorial Influenza Screwupsynapsisdislexium - which as you know is a terrible condition - I have only perhaps 45 years to live tops. I have been out of action now for quite some time - at the end of today it will be . . . . . yep, 7 whole hours. Yep, thats it guys, its finally got me - The Common Cold. I would like to thank everybody for tolerating me over the years, and please leave my Canary `Boeing` to some nice old lady - who will look after him and stuff him full of food and let him out of the cage, twice a day, he will find his own way back in again.

Back to the problem, which I am trying to solve before the great partyer in the sky takes me to heavens where all the babes are blonde 25 and non virgins. . . .

. . and with my last dying breath:

SKYbrary - Altimeter Temperature Error Correction
>
>

Jammedstab,

Yes, it made me slightly high but as you say it's conservative and no safety issue. I should have twigged when the ATIS had Fata Morgana on it.

And I'm pretty sure the basic formulae work on a standard lapse rate.

There's a more complex one that even takes into account the variation of 'g' with altitude, but you won't be doing that in your head!

I can't type out the formula on the screen so I'll see if I can find a copy online.

That could be interesting when separating from other traffic that is not using the QFF correction. Expect some queries from ATC on why you are not at the altitude you were cleared to.

Eventually, everyone will move to GPS/GNSS GBAS altimetry as most airport procedures become Vertical RNP and LPV rather than 'baro aided'.

this should be in place by when, 2050?

It is probably technically feasible now especially in the TMA/TRACON and associated RNP approach procedures. Some approaches with LPV are already using GPS for vertical guidance.

Read NASA ASRS and look at the huge number of altimeter setting errors in air carrier aircraft; for safety alone GPS altimetry could be justified.

Procedures are there, but not all aircraft can fly them (yet),even the NG is only Baro-VNAV approved. Let's hope this changes with the MAX.

GBAS is already available on most commercial aircraft, in fact, for most, it is free, one just has to ask for it to be installed.

GBAS systems are installed at virtually NO airports.

The FAA is reluctant to consider GBAS at the airports becuase they consider GBAS as a single point failure system. (and they spent a bazillion dollars on things like MLS and WAAS)

GBAS is NOT RNP. There are RNP transitions to a GBAS final procedures, but RNP and GBAS are independant.

RNP procedures use non-comp baro-vnav for vertical guidance. GBAS provides vertical guidance with an ILS look alike, but unlike ILS as a beam, GBAS is a signal which isnt interrupted like a beam, and contains all of the approach guidance.
Yes, the GBAS signal can even include turns.

Getting past all of these issues with the regulators has taken many, many years. The aircraft that are already equipped to use GBAS will be recycled into beer cans before the onboard system is ever used.

I understand, but really, ONE airport in the world has GBAS?

Just ask the FAA what a disaster GBAS has been at Newark and George Bush..

They will probably move the GBAS from Sydney to Melbourne.

Again, The aircraft that are already equipped to use GBAS will be recycled into beer cans before the onboard system is ever used.

GBAS implementation program | Airservices

Airservices Australia to deploy Honeywell SmartPath precision landing system at Sydney Airport 14 February 2013
Airservices Australia to deploy Honeywell SmartPath precision landing system at Sydney Airport - Airport Technology

Seems that Air Services Australia is doing more than you think

Europe is also putting prototypes out
SESAR Prototype CAT III GBAS in Operation -- OSLO, Norway, May 31, 2013 /PRNewswire-iReach/ --

GBAS CAT I station to be implemented at Frankfurt Airport - Via Satellite

India are also implementing

Chennai airport to get India's first SmartPath GBAS - Economic Times

You may be right about the use of GBAS in the US NAS though

This doc should tell you most of what you need to know.

http://www.caa.co.uk/docs/2261/20120...onDocument.pdf

I would take most if not virtually all of that information with little basis in reality, especially that map provided...

The news brief on AirServices and Sydney. I am not sure where that came from, but this is from the Airservice Australia website:

Phase 1
Airservices has completed Phase 1 to build operational experience with GBAS technology, using a Honeywell’s demonstration GBAS, SLS-3000, at Sydney International Airport.

In November 2006, Airservices and Qantas launched the world’s first GLS approach. Since then, Qantas has flown more than 2,500 GBAS-supported approaches and trained over 700 pilots on GBAS operations. Pilots have consistently reported that GBAS provides extremely smooth and stable guidance. Qantas is equipping its entire B737NG fleet with GLS. In January 2009, Qantas obtained CASA approval of GLS operations on Airbus A380s. In the coming years, over 50 per cent of Qantas aircraft fleet will have GBAS capabilities.

Phase 2
Phase 2 commenced in the third quarter of 2009 to replace the Honeywell SLS-3000 system with the SLS-4000 SmartPath™ GBAS at Sydney. SmartPath™ is the world’s first and only GBAS which has received the US Federal Aviation Administration (FAA)’s system design approval. Airservices and CASA closely monitored this approval process.

Acceptance testing of the new system was carried out in August 2011 and a three-month test and evaluation period commenced in late 2011. Airservices intends to apply to the CASA to have GBAS Category I (CAT-I) operations approved for use at Sydney during 2012.

GBAS implementation program | Airservices

At this point in time, I believe it has been decided to moved the GBAS system from Sydney to YMML....

First off, the Russians jumped the boat on GBAS, and the system is not compatible with the current ICAO protocols. If you look at the Russian AIP, you will see that there are currently no operational systems in the country.

The European prototype is just that, a prototype.

The units listed in Norway, SCATI is DGPS, not GBAS.

Honeywell has deployed its SmartPath at Bremen, Germany, and is currently operational at Newark Liberty International in the US, while the systems are being deployed at Rio de Janeiro in Brazil, Malaga in Spain, and Memphis, Tennessee, and Houston, Texas, in the US.

While I am not sure of the operation in Bremen, it is shutdown in Newark due to the interferance issues (the poor siting decision of the antenna) and is being moved to Houston. Malaga and Memphis, well, those are perhaps HW dreams...

Basically the opposite. That is how I know what is operational...

(just got back from a meeting with United and Delta...they wish the GBAS had been online given what just happened in Newark)

OK,

I am checking back with the Chiefs on this. The last I was aware, the system was down until HW can provide a more robust signal not prone to jamming or other interference.
We had just been talking about RNP to GLS final, but they told me there was currently no operational system in the US to look at this potential.

We were also under the impression that the FAA isnt really going to support GLS as a single point operation due to the assumption that it is a single point failure scenario.

Agian, I will get back to you as soon as I get a response.