Cold Weather Corrections - Departures

[Gards]

There is a small debate happening within my company as to whether or not you correct minimum published altitudes on Departures in a radar environment.

Question is to Terminal and Approach controllers. Are the published minimum altitudes on a SID designed to take into account cold weather effects on altimetry? In other words are you expecting or NOT expecting pilots to correct for these altitudes?

Thanks to anyone who can point me to a documented reference either way!

[HEATHROW DIRECTOR]

I worked as an ATCO for most of my life and never heard of cold weather corrections so I don't think it's common practice.

[TheChitterneFlyer]

It's my understanding that if you intend to apply Temperature Error Corrections to your altimeter to, either, a FAF crossing altitude, procedure turn, or missed approach altitude, pilots must advise ATC of their intention and the correction that they're applying.

Pilots may refuse any IFR assigned altitudes if temperature error will reduce obstacle clearance below acceptable minima. However, once an assigned altitude has been accepted, it must not subsequently be adjusted to compensate for temperature error.

TCF

[Inner_Ninja]

I worked as an ATCO for most of my life and never heard of cold weather corrections so I don't think it's common practice.

As I believe you don't very often experience -20C and below in the UK very often, of course it's not common practice there.

To provide real world experience on top of the excellent info form TheChitterneFlyer and LookingForAJob, I have had a pilot inform they were applying temperature correction in an overshoot/go-around situation, with the published missed altitude of 4 000 feet, and the Mode C when they leveled was 4 300 feet (it was _VERY_ cold out). Never seen it on a standard departure, but if an aircraft was vectored off a SID, the temperature corrected MVA should be used by ATC. I would not expect temperature correction to be applied by the drivers.

[M609]

DOC4444:

8.6.5.2 When vectoring an IFR flight and when giving an IFR flight a direct routing which takes the aircraft off an ATS route, the controller shall issue clearances such that the prescribed obstacle clearance will exist at all times until the aircraft reaches the point where the pilot will resume own navigation. When necessary, the relevant minimum vectoring altitude shall include a correction for low temperature effect.

---------lenght

[rodan]

The current UK position is in CAA IN 2013/020. Essentially, we are aware that aircrew might request a higher altitude, but we have no procedures of our own until a common European practice is agreed.

[Inner_Ninja]

TC RAC-AIM 9.17.1 also speaks to temperature correction (I'm guessing you're in Canada, as I believe Spruce Grove is near CYEG)

[Gards]

Not in Canada

No actually I am in south east asia but indeed I am Canadian. I am very much aware that an assigned altitude is not corrected for by pilots ie. Radar vector, taken off a sid, etc. But my question is specific to Published Departure Procedures only. STARS and Approaches you need to correct. But the discussion we are having, which is coming from another Canadian, is that you do NOT correct for published altitudes on a SID in a RADAR environment. For the life of me I cannot find an exact reference that backs up this claim.

I myself always corrected when it was cold on all published altitudes no matter in departure or arrival. But I am being told ATC does not expect this for departure. Again only on published altitudes on a sid and in a radar environment.

Any one ever see a reference in a document that would indicate this?

Thanks!

[MarkJJ]

Had the same chat in my company, on SID no correction required, I have heard pilots saying they are correcting on a SID out of Goose Bay, but they were vectored on course with further climb anyway. If your SID is canceled at any point and one is cleared on course, it will come with the caveat of 'at your discretion', as your now not on the SID, terrain clearance is now solely PIC responsibility.

[JeroenC]

We temp correct *everything* below the temp corrected MSA when <0 degrees, unless vectored. Ofcourse we inform ATC

[jmmoric]

Here we have a MSA of 5300 ft, and a SID that only says something in line of "track extended centreline until 5300ft", we expect pilots to add for cold weather if they want to fly it. The SID is a little straight forward since some companies didn't want to fly out in poor weather unless they had a SID, so we invented/described what everyone have been doing for the past 40+ years.

It's usually not a problem, since when the radar is working the minimum vectoring altitude in the departure area is merely 4000ft.

What we do is add up for wind and temperature to the 4000ft, and advise the pilots of the MVA in the area. That usually is good enough for the pilots, but in the event they want to keep climbing towards 5300ft, and we need them to turn we use the phrase "under radarcontrol turn...." after we verified their altitude readout.

When the RADAR is out of service, the lowest is just 5300ft (MSA), and when using that we add a little "not temperature corrected", then pilots will more often than not advice what altitude they use (or we will simply ask if needed).

The temperature can drop below minus 40 degrees celcius in wintertime, and with the mountains we take both wind and temperature into account when calculating minimumm vectoring altitudes.

But seing pilots climbing to 5300ft before starting their turn on course on a sunny warm summerday, always makes me cry a little inside. Must be way more dangerous to fly IFR in sunny conditions than VFR?