Cold Weather Corrected Missed Approach Altitude

[co-joe]

It's called logic and airmanship

Exactly.

[nynybear]

The Missed Approach Altitude is an AT constraint, therefore in a radar environment flying to a corrected Missed Approach Altitude could result in a loss of separation and should not be done. In an emergency and/or loss of comms the terrain clearance takes precedence so have the corrected altitude available for that rare scenario. If operating in a non-radar (or non-ADS in the future) then correct and fly it only if it is below the applicable corrected MSA.

Happy flying!

[gonnabeapilot]

The Missed Approach Altitude is an AT constraint, therefore in a radar environment flying to a corrected Missed Approach Altitude could result in a loss of separation and should not be done. In an emergency and/or loss of comms the terrain clearance takes precedence so have the corrected altitude available for that rare scenario. If operating in a non-radar (or non-ADS in the future) then correct and fly it only if it is below the applicable corrected MSA.

Happy flying!

Where is it written that all missed approach altitudes are exclusively air traffic constraints? If it is not every single missed approach altitude how is a pilot supposed to know whether the missed approach altitude was selected for air traffic or terrain reasons? There are obstacles present in all environments, not just in mountainous terrain. These obstacles don't magically disappear because the aircraft is operating in a radar environment. As PIC your duty is to protecting your passengers, not making the life of a controller easier.

RAC 9.17.1 is pretty clear. You are required to correct the charted missed approach altitude and you are required to inform ATC of the correction. In terms or airmanship, one of the first things you're going to do in a missed approach is communicate to ATC that you're in the missed approach. Adding "climbing to 5200, temperature corrected" takes an extra second. If ATC doesn't want you there because of air traffic concerns they will assign you a radar safe missed approach altitude. If you enter a lost comms scenario and can't inform ATC you're meant to squak 7600 and guaranteed ATC will be clearing all air traffic out of your way until they figure out exactly what you're doing. If after all of that you're still concerned about traffic TCAS provides an extra layer of protection against traffic conflicts. Temperature correction is your only layer of protection for terrain avoidance.

The only real reason people ignore the instructions in RAC 9.17.1 is laziness, pure and simple. Aside from the military instructions posted here (an interesting read) there is nothing in black and white that absolves a pilot from doing it. Talking about airmanship or ATC concerns is vague at best and based solely on some made up opinion about what should be right. Take the extra ten seconds, correct the altitude. It won't kill you but not doing it might.

[AuxBatOn]

Where is it written that all missed approach altitudes are exclusively air traffic constraints? If it is not every single missed approach altitude how is a pilot supposed to know whether the missed approach altitude was selected for air traffic or terrain reasons?

Well, if the missed approach altitude is above the MSA,
that’s a pretty good indication...

RAC 9.17.1 is pretty clear.

Clear? What is the definition of “extreme cold temperature”?

[flyingvinnie]

Pretty clearly explained in the CAP.

It’s not if you’re in a radar environment, BUT on radar vectors.

[AuxBatOn]

Pretty clearly explained in the CAP.

It’s not if you’re in a radar environment, BUT on radar vectors.

Not really. Still doesn’t define exactly when you need to temperature correct the altitudes. Just what you need to do when you have to.

[nynybear]

We are all laboring the same point (albeit with varying hostility and condescension). I don't think anybody here needs to be told what the role of PIC is.

In order to clarify my original statement let me add this "...could result in a loss of separation and should not be done without approval." This is only for a radar environment and is different than just informing. In non-radar and below the corrected MSA then always apply and fly the corrections and inform ATC.

The MAA constraint is always an AT constraint for either ATC or terrain because both would need to be considered for the construction of the approach and the surrounding airspace. With 1000' being common separation in a TMA, I personally don't consider mitigating a fly down RA mid-missed approach to be making a controllers life easier. Some airports/airspace are simultaneously very cold and very busy.

As I assume you are not just going to correct for cold temperature within the borders of Canada so you may find in other regions of the world that your easy ""climbing to 5200, temperature corrected" could get you a big WTF from ATC. Obviously leading to more confusion and wasted time and resulting in radar vectors anyways.

As for air traffic or terrain being critical, I believe AuxBatOn said it best.

As for RAC 9.17.1, it is far from exhaustive on cold temperature altimetry and is written largely with small, sleepy little Canadian airports in mind.

Could you imagine everybody doing this in YYZ, JFK, DEN, INC or NRT for just a few cold weather airports. They would need a separate frequency!

4. When altitude corrections are applied to a published
FAF crossing altitude, procedure turn or missed
approach altitude, pilots should advise ATC how
much of a correction is to be applied.

[2R]

One of the neat features of the newer GPS displays is they can display GPS altitude discretely on the screen .
Fun to watch the altimeter ,radar altimeter and GPS start to agree on descent.
Who knows maybe we will be given GPS altitudes to fly in the future

[nynybear]

One of the neat features of the newer GPS displays is they can display GPS altitude discretely on the screen .
Fun to watch the altimeter ,radar altimeter and GPS start to agree on descent.
Who knows maybe we will be given GPS altitudes to fly in the future

New aircraft like the A350 already use the MFD temp input to temperature correct the glide slope when carrying out a non-precision approache using the FLS in F-GS mode. It will also detect speed and altitude faults and replace the traditional outputs with speed produced from the AOA/FADECs and Altitude from the GPS.

Neat stuff if only Canada would have some...

[ahramin]

Or, copy the FAA and publish a list of any airport that could possibly require a cold weather correction, the temperature below which a correction is required, and which segments need to be corrected.

https://www.faa.gov/air_traffic/publica ... 19001.html

Wow.

"Require final holding altitude, 10600 ft. on missed approach for cold temperature operations."

[Parkex]

Pretty clearly explained in the CAP.

It’s not if you’re in a radar environment, BUT on radar vectors.

Pilots "should" not shall.

cold temp corrections are not law, they are a recommendation.

I personally think they are useless 99% of the time.

The only time you actually have a chance of being saved/remotely safer with these are in a non-radar environment where the terrain is actually an issue.

Any time that a cold temp correction is actually going to add any real value in terms of safety is at extremely cold temperatures... and it's probably just going to be VFR at that point anyways.

Seriously, you have a fatter chance of creating a traffic conflict with a corrected alt that you do of not hitting a mountain.

Mins should be the only mandatory cold temp as you could actually bust the AGL altitude of the mins if not corrected.

my 2 cents

[2R]

Cold weather corrections are important , if you are flying through mountainous areas be aware of the venturi effect that strong winds can create local lows and your true altitude could be a lot lower than you think .
Remember Bob Heath . 100 mph winds and mountain wave . If you are imc you might not see it coming .