Standby Altimeter setting procedure

[airbond]

Question regarding standby altimeter setting procedures.

What is your company policy, or your procedure on when to set 1013 or local QNH on standby altimeter.

Presently when I reach TOC I set 1013. And on TOD I set local QNH.

[LEM]

http://www.pprune.org/forums/showthread.php?t=89867

[airbond]

Thanks for link.

I guess its up to the Captain on standby altimeter setting.
Nothing in our SOP's written.

After flying jets for the last 8 years, and trying a few ways, I find the best way is to set on climb 1013 at 10000ft or TOC and on descent local QNH at TOD or passing 10000ft.

[Piltdown Man]

Given the choice, I'd set my standby altimeter on regional or airfield QNH. Then, at all times whilst on "standard" I'd at least have an idea of my altitude and if it was really important, have a figure to quickly plug into the formula for calculating true atitude. Unless of course, it was doing the job for which it was actually installed for.

[Old Smokey]

Our procedures are to set the Standby Altimeter 'in line' with the Primary Altimeters, i.e. QNH at start-up, and Standard at Transition Altitude during Climb. Where this differs slightly, is that QNH is set for the Standby Altimeter alone at Top of Descent, in advance of Transition Level, where QNH is set on the Primarys.

It's a fairly new SOP, frankly I'd prefer to keep the Standby Altimeter in line with the Primarys at all times.

Regards,

Old Smokey

[Gary Lager]

Our SOPs:

Standby Altimeter to 1013 on passing 10000' or sector MSA, whichever higher. Primary altimeters are set to 1013 when cleared to a FL so SBY provides terrain reference whilst still below Transition/MSA.

SBY set to arrival QNH shortly before TOD, as in your new SOP. We complete Descent Chx before TOD; part of which is to set said SBY Altimeter to arrival QNH. This provides a terrain clearance gross error check during descent for the event that the selection of QNH on primarys is missed (it has happened!!). If a discrepancy is noticed between the two primary altimeters (whilst still above TL) then it is a simple procedure to reset the SBY to QNE and perform the required cross-check.

[BOAC]

Perhaps the mods here could merge the linked thread with this? In the meantime, slightly modified from that thread, is my postBA's procedure (737) is to set 1013 when above acceleration altitude (normally 1500' QFE) and cleared to a FL (no mention of within 2000'), but the standby remains on QNH until above MSA and TA, so is normally available for an altitude check

To add: my understanding is that a common (UK) SOP is as above, with the addition that the standby is set to destination (or area?) QNH when dropping out of RVSM airspace. To add to LEM's point regarding approach checks - in my experience these are done when cleared to an altitude, not at TL.

A question on US procedures, since no-one appears to have answered 'DFC's' question. If you were to fly 1000 miles at 15000ft, do you constantly change the altimeter setting along the route and if so when and from where does the info come?

As a final point I agree with Captain Peacock that "A good dose of Commanders discretion required" since one size rarely fits all all the time.:)

[blck]

Our SOPs:

Standby Altimeter to 1013 on passing 10000' or sector MSA, whichever higher. Primary altimeters are set to 1013 when cleared to a FL so SBY provides terrain reference whilst still below Transition/MSA.


Definitely, you are not from US where it is prohibitive (QNE setting before TA) :)
But your SOP related STBY is really good. :ok:
In my experience, the STBY is set together with main gauges.

[alf5071h]

Considering the regulatory view of why a standby altimeter would be required, then the use of the same pressure datum as the main altimeters would be more appropriate.

If both main altimeters (ADCs) fail then the standby is already set to the datum in use; alternatively if the standby system is required to resolve an ambiguity between the main altimeters (comparator alert) then the pressure datum in use enables a quick check.

Resetting the standby altimeter also provides an additional error check as one pilot is required to set the pressure datum twice, which should require a cross check with both main altimeters.

[I-2021]

In my personal opinion it is better to have the same information on the 3 altimeters. The stby altimeter is, as its name says, a stand by tool and therefore you must have the chance to cross check the main altimeters with the same reference datum, i.e 1013 or QNH. I know that many people use to set the local QNH on the stby during cruise as soon as they know the destination airport QNH. That can be useful in case of an emergency descent, but anyway if you perform an emergency descent you will ask anyway local QNH for the area you are overflying to comply with GRID MORA. The point is that I prefer (IMHO of course) to have the same data on all the sources of informations (altimeters) so when I change one thing, I change everything. I prefer to forget std 1013 on the stby, and landing with QNH set on main altmts that lading with 1013 on main altimeters and the QNH on the stby. Last thing, some aircraft may have the pressurization screwed up by incorrect stby altimeter setting.

[Capt Claret]

In the Co I work for, SOP for the last 10 yrs (perhaps longer) has been STD Press at Transition Alt on climb (A100 in Oz), and on descent, once cleared to a level below Transition Level (FL110 in Oz) the SBY ALT is set to QNH whilst the crew altimeters are not set to QNH until the Transition scans are conducted.

[Mr.Buzzy]

Hi Clarry,
we do exactly the same as you mentioned in your last post. We also operate 737 in OZ.
regards
Buzzy

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