Radio Altimeter Call Out on A320

[Maverick2167]

What could be the reason if the Rad Call out on the A320 missed a callout during short finals, say after 50ft callout over the threshold it calls out directly 30ft and missed the 40ft Call out? assuming ILS 3 degree approach and no excessive VS.

[iggy]

What could be the reason if the Rad Call out on the A320 missed a callout during short finals, say after 50ft callout over the threshold it calls out directly 30ft and missed the 40ft Call out? assuming ILS 3 degree approach and no excessive VS.

I have seen that happening, and what baffles me the most is that it always happens in the same runway and at the same spot! In my case, the missing call out was 100'.

So no, no idea why... Maybe a slight change in terrain makes the RA go nuts for just a few seconds?

[Maverick2167]

I have seen that happening, and what baffles me the most is that it always happens in the same runway and at the same spot! In my case, the missing call out was 100'.

So no, no idea why... Maybe a slight change in terrain makes the RA go nuts for just a few seconds?

In my case went to the airport numerous times, this was the first time it happened. I was wondering if Low level windshear could be at play i.e. momentarily pushing you down or something

[Check Airman]

Sometimes Fifi has hiccups and just does that. No rhyme or reason that I’ve seen.

[k.swiss]

Can happen if the height drops fast, maybe a hill, it will not call out both at once.

Also on a side question, do you call "RAD ALT ALIVE" every time as a standard callout, or only if the pre-programmed callout is missing?

[Maverick2167]

Can happen if the height drops fast, maybe a hill, it will not call out both at once.

Also on a side question, do you call "RAD ALT ALIVE" every time as a standard callout, or only if the pre-programmed callout is missing?

“Rad Alive” is a standard call out in my Company with or without the pre-programmed. In my case it was just after 50ft Rad call out i.e. 50ft over the threshold and next call out was 30ft, there wasn’t any excessive VS

[Uplinker]

This is only a guess, but there could be two reasons:

1) One of your aircraft might not have the 40' call out pin programmed - the Engs might have missed that one. So on a given day, in one airframe you hear it, on another day in another airframe, you don't !

2) There might be something on the ground around that spot that absorbs or affects the Rad Alt transmission, to the point where the reflected transmission is too low a level or too distorted to be registered by the Rad Alt receiver.

[Rico_Corp]

Into Kathmandu RWY 02, you’re lucky to get 2 callouts below 50 ft. Last time I went there (A330) we only heard 50, 10 then retard etc due to the moderately sloped pre-runway environment.

As for the PM “RAD ALT ALIVE” callout, if your operator uses Airbus procedures it is normally only announced if the auto-callout is inoperative.

[sonicbum]

Can happen if the height drops fast, maybe a hill, it will not call out both at once.

Also on a side question, do you call "RAD ALT ALIVE" every time as a standard callout, or only if the pre-programmed callout is missing?

Hi,

"Radio altimeter alive" should be called every time the radio-altimeter becomes alive, i.e. 2500 ft RA. In addition, if the pre-programmed call-out "two thousand five hundred" does not work, the PM will announce it.

"To enhance the flight crew’s terrain awareness, a callout “Radio altimeter alive”, should be announced by the first crewmember observing the radio altimeter activation at 2500 ft height AGL."

Altimeter Setting - Use of Radio Altimeter (https://skybrary.aero/sites/default/files/bookshelf/192.pdf)

[crazypilot]

Perhaps that aircraft simply didn’t have the 40’ call installed - at my airline, we don’t have the 40’ call-out on any fleets, short haul / longhaul, Airbus or Boeing (takes a bit of getting used to after having it at a previous operator but you do get used to it..)

[Rico_Corp]

"To enhance the flight crew’s terrain awareness, a callout “Radio altimeter alive”, should be announced by the first crewmember observing the radio altimeter activation at 2500 ft height AGL."

Just to be clear, FCOM does not specify this anywhere (that I can find). The quoted FOBN is from 2005 and “shall not supersede” FCOM as per the footnote.

[sonicbum]

Just to be clear, FCOM does not specify this anywhere (that I can find). The quoted FOBN is from 2005 and “shall not supersede” FCOM as per the footnote.

Hi Rico,

The FCOM mentions: PM -------> RADIO ALTIMETER ALIVE(1)(2)

two notes there.

(1) Flight crew awareness, flight crew should now keep RA in scan to landing.
(2) PM monitors pin-programmed auto callout, or announces if inoperative.

The first note tells us the callout is done for flight crew awareness and to keep the RA in scan, so as the FOBN mentions.
The second note tells us to monitor pin-programmed callouts and announce if inoperative, i.e. 2500, 1000, etc..

In normal Ops that would be: autocallout "two thousand five hundred". PM: "radio altimeter alive". PF: "checked" (if it's actually displayed of course)

[Rico_Corp]

Hi Rico,

The FCOM mentions: PM -------> RADIO ALTIMETER ALIVE(1)(2)

two notes there.

(1) Flight crew awareness, flight crew should now keep RA in scan to landing.
(2) PM monitors pin-programmed auto callout, or announces if inoperative.

The first note tells us the callout is done for flight crew awareness and to keep the RA in scan, so as the FOBN mentions.
The second note tells us to monitor pin-programmed callouts and announce if inoperative, i.e. 2500, 1000, etc..

In normal Ops that would be: autocallout "two thousand five hundred". PM: "radio altimeter alive". PF: "checked" (if it's actually displayed of course)

Sure Sonic, if that is your operator's interpretation, its all good. Last 3 Airbus operators I have flown with, the interpretation of Note 2 was (my addition in brackets):

(2) PM monitors pin-programmed auto callout, or announces (RAD ALT ALIVE) if inoperative.

[sonicbum]

(my addition in brackets):

(2) PM monitors pin-programmed auto callout, or announces (RAD ALT ALIVE) if inoperative.

That's where the very common misunderstanding usually comes from. We had the same type of discussion for quite some time till we clarified with Airbus directly.

"Radio Altimeter Alive" is not a pin-programmed callout, so note 2 cannot be applicable to this specific callout. It can only be applicable to the "2500" callout.

If You get this type of discussions too You might want to drop an email via Your tech pilot to Airbus customer tech assistance or via the Airbus World website to get an official answer.

[Superpilot]

I would say some unusual environmental/atmospheric/ground temperature condition or maybe electromagnetic interference or radio frequency disturbance. 5G? :E And so the RA gave "30ft" when in reality it was higher. Tell us which airfield and date/time or if you have it the METAR.

[Fursty Ferret]

It’s just weird sometimes. I even heard “92” once on an A321, something that was completely new to me and which had no explanation forthcoming from the flight technical team.

[AerocatS2A]

That's where the very common misunderstanding usually comes from. We had the same type of discussion for quite some time till we clarified with Airbus directly.

"Radio Altimeter Alive" is not a pin-programmed callout, so note 2 cannot be applicable to this specific callout. It can only be applicable to the "2500" callout.

If You get this type of discussions too You might want to drop an email via Your tech pilot to Airbus customer tech assistance or via the Airbus World website to get an official answer.

Very interesting. I much prefer my operator’s version where the PM is silent in normal ops but I don’t doubt your interpretation is correct.

[Black Pudding]

(2) PM monitors pin-programmed auto callout, or announces (RAD ALT ALIVE) if inoperative.

And here is where we have the problem. We have those flying the A320 who insert (RAD ALT ALIVE) in places in the manuals where it’s not meant to be.

2) PM monitors pin-programmed auto callout, or announces if inoperative. Means the actual call outs that would be made by the aircraft, not RAD ALT ALIVE

What does it say in your NOPs STANDARD CALLOUT for PM when RA alive. What are those 3 words to be said by PM just like the word in the above column of APPROACH PHASE ACTIVATED and the column below GA ALTITUDE SET.

[AerocatS2A]

Ours says “RADIO ALTIMETER ACTIVE - if no 2500 call-out”. This isn’t pilots making stuff up, the interpretation is embedded in the SOP.