When to set 1013 in the climb?

[Crosswind Limits]

I don't know if this is the appropriate forum but here goes anyway.

When should you set 1013 in the climb to a flight level? Is it as soon as you are cleared to a FL or only within 2000 feet of the transition altitude?

Cheers.

[Spitoon]

Rules in the UK are given in the AIP (http://www.ais.org.uk/uk_aip/pdf/enr/20107.pdf).

It's been discussed in Tech Log (http://www.pprune.org/forums/showthread.php?threadid=56742=50291) recently.

[Captain Stable]

In the UK rules are that you should set 1013 when within 2,000 ft of the TA in the climb and cleared to a flight level. Not before. And not later than passing TA.

[shlittlenellie]

Captain Stable, not so.

In the UK, 1013 will be set when cleared to a flight level unless altitude reports are required. There is no reference to "within 2000 of the TA".

Quoting the AIP,

"Within Controlled Airspace a pilot should set one altimeter to the latest Aerodrome QNH prior to take-off. While flying at, or below, the Transition Altitude vertical position will be expressed in terms of altitude based upon the Aerodrome QNH. When cleared for climb to a Flight Level, vertical position will be expressed in terms of Flight Level, unless intermediate altitude reports have been specifically requested by Air Traffic Control."

[t'aint natural]

'ang abaht.
My copy of The Air Pilot's Manual Vol 2, Aviation Law, by Trevor Thom (may his tribe increase) sez:
"WITHIN CONTROLLED AIRSPACE:
After clearance to climb above the transition altitude has been given and the climb commenced, vertical position will (unless specially requested otherwise by ATC) be expressed as a flight level, provided that the aircraft is not more than 2,000 feet below the transition altitude."
So the confusing "2,000 ft" bit refers not to when you can change to standard pressure, but when you can express altitude as a flight level.

[Crosswind Limits]

I think you are right Shlittlenellie but what happens if you are climbing to a flight level from uncontrolled airspace? I will check the AIP when I next get the chance.

[Capt Claret]

I can recall an incident only a few years ago ex Perth (AUS) where two jets were told to stop climbing/descending as some stuff up resulted in them either losing or coming close to losing the required separation.

Another consideration is that if there is a big split between Area QNH & 1013, and one changes the altimeter setting too early, the risk of a false sense of sepparation being passed on is greater.

Mindful of this I try to set 1013 once within 500' of transition altitude.

[Nugget90]

I had a hand in writing the Flight Operations Department Communication (FODCOM) 2/97 which contained what we thought was very clear advice to the operators of public transport/commercial air transport operations on altimeter subscale setting procedures, and was closely involved in the research that the UK CAA undertook to find out what could be the causes of altitude/level busts.

Within this FODCOM, which can be accessed through the CAA website (www.caa.co.uk/docs/33/FOD199702), the topic of, 'When to set Standard (1013/29.92)' received special attention.

As it was evident that many pilots failed to set 'Standard' when the rules required the subscale setting to be changed 'on reaching Transition Altitude' due to distraction, failure to remember what it was, etc, the requirements changed to what appears in the UK AIP today. It was also evident that not setting Standard until passing TA on occasions when the pressure was low simply invited high performance aeroplanes to zoom through their cleared level before the adjustment could be completed and cross-checked.

The only procedure to be followed is that specified by the operator. For the pilots of UK-registered aircraft this should be along the lines of, 'Immediately after being cleared to climb to a flight level, set and cross-check that 'Standard' is set, then commence the climb.' The only exception to this rule is where State regulations require that this adjustment is made close to the TA, such as in the USA, where the TA is relatively high. It is ususal for many operators to require that the third altimeter remains on QNH until the aircraft has passed above either the TA or the Minimum Safe Altitude, whichever is the higher, so that there is a means of rapidly knowing altitude if the need arises.