Altitude Preselection

[Skidmark]

There are always more than one way to skin a cat. So what I'd like to know is the varying ways, minor though they should be, of setting the altitude preselector on leaving an initial altitude for an MDA/DA. In particular, the setting of any further cleared/step altitudes and when setting the missed approach altitude.

[Tankengine]

Left hand/right hand, thumb up/thumb down?:confused:

Ahh, more detail after edit.

: most likely is setting missed approach altitude.

[Howard Hughes]

The procedure at all of organisations where I have worked, is to set the missed approach altitude, with DA set on the radalt.

[skkm]

DA/MDA bug will already be set to the DA/MDA. Commencing the approach I set the assigned altitude bug to the initial missed approach altitude.

[Capn Bloggs]

Skidmark, does yours have a departure warning, does the AP or Flight Director use it to level off, or is it just a manual thingee on the panel? Do you do Continuous Descent NPAs (Derived Decision altitude), do you fly level into the Missed Approach Point then do your Missed Approach? Do you have a rocket-ship that climbs like a b#$^#@# when you go-around, are you single pilot?

[Skidmark]

I work in a multi crew aircraft, which can climb like a "rocket ship". We use the continuous decent method whereby decent maybe delayed to facilitate a constant rate to the MDA from the IAP/hold. Once at the MDA if not visual, fly level to the MAPT then if not visual the MAP ALT is set, if visual, circling ALT is set. In the case of a precision approach, the DA is set on the ALTSEL and the DH set on the RADALT. At the DH/DA the MAP is initiated and the non flying pilot sets the MAP ALT on the ALTSEL.

My reason for asking is simply for curiosity. A discussion based on pros and cons of our method versus others of setting the MAP ALT from the commencement of the approach as a couple others have already stated.

Hope this answers your query.

[morno]

Once at the MDA if not visual, fly level to the MAPT then if not visual the MAP ALT is set

I'm curious as to why you would then fly level to the MAPT if you're already flying a constant descent? If you're at the MDA where the approach plate says you should be, then anything past that is simply going to create an unstabilised approach when you have to 'dive' to get back on profile.

morno

[Captain Nomad]

anything past that is simply going to create an unstabilised approach when you have to 'dive' to get back on profile.


Not necessarily if it is a circling approach.

If it is an altitude preselection function which is tied into an A/P the aircraft manual will probably also stipulate limitations on how this can be used (ie. not for altitude 'capture' below a certain altitude for example).

Setting initial missed approach altitude makes a lot of common sense as a SOP.

At the end of the day, fly by the aircraft manual and your company Operations Manual. Fly outside of that and you could be hung out to dry.

[Mach E Avelli]

In every installation I have flown, once the ILS glideslope is captured, altitude preselect is over ridden. So it may as well be set to missed approach altitude.
But for every other type of approach, it makes sense to set it to the MDA or circling minima, as it will at least provide some protection if the auto pilot or flight director is in use, or you go more than 100 ft low while hand flying on raw data. A constant path descent to a runway should not become destabilised by this if the auto pilot is disengaged at the alert, which is typically between 100 ft and 300 ft before the altitude set. Most pilots flying a non precision approach to a runway would probably disconnect the automatics about then anyway. On the other hand, if flying a circling approach, most would probably elect to keep the autopilot engaged until late downwind. Once the circling altitude is captured, set missed approach, just in case visual contact is lost.
This is recommended by Flight Safety Foundation, which also recommends using RADALT as a back up for all instrument approaches. Even if RADALT is set 100 feet below DH or MDA, it does provide a final chance at an alert if somehow the crew have lost altitude awareness. Easy enough to do at unfamiliar airports above sea level.
Having said that, the manufacturer FCOM or company SOP rules, OK?