Airbus Alert Height - What is it?
 

Could anyone explain:

1. Definition of Alert Height
2. The significance of it.

Check this:

http://www.pprune.org/tech-log/34874...ii-minima.html

Thanks Hetfield. Appreciate the help.

So I understand the definition now but how is it used in practice?

I see that in some EUR regulation here, that they say:

- -

Just used it this morning (A319, RVR 125).

I called out "ALERT HEIGHT" at 100 ft RA

Captain checked that everything worked fine and called out "CONTINUE"

Uneventful autoland ensued.

In practice during CAT III DUAL NO DH approach, before Alert height, we would have gone around for folowing indications

-alpha floor activation
-AP off
-loss of CAT III dual
-amber caution
-engine failure
-no LAND mode at 350 ft
- incorrectly displayed loc course at 350 ft
- NWS or antiskid failed

Below alert height we'd go around only in the case of autoland warning light. It goes off if both autopilots have failed, excessive deviations or loss of loc / G/S signal is detected or difference greater than 15 feet between radalts exists.

Never heard of it. Never used it.

Airbus P1, 4000+ hours on type.

Edited to add - checked the Airbus FCOM 3 and there is a reference there to AH of 100 ft. However in our SOP's we would initiate a go-around for any failure resulting in a warning, caution, Cat downgrade etc. below 1000 ft RA. Probably explains why the AH doesn't register.

Spin Doctor,

you're saying that with over 4000hrs on Airbus aircraft (Assuming A320 series), you were less that Alert in relation to Airbus SOPs?

It's called "Fail Operational" and is of significance when you are operating Cat 3B with no DH.

I found this in my company's operation manual. I guess I should have started here in the first place but thought I'd include it in this thread for information purposes.

..........Thats the big red light in front of you.

Below Alert Height....
IF that flashes - manual go-around. If that stays dark, no need to assess the failure - autoland ahead.

Check... Fully understood now. Thanks for the help gentleman.

@Nocti

Don't be too harsh with spin doctor...;)

I'm flying varios AB in the same company since 1989 but we startet with the ALERT HEIGHT when we adopted CAT IIIb 0-75, about six years ago....

regards

"alert Ht"
 

Funny, we have recently dropped the call to align with the Boeing a/c in our fleet, it has struck me as odd since I thought it was a/c spacific.
anybody got any brighter ideas?

DL

ah, but what if you get no FLARE annunciation at 30'R?

No experience of cat 3B ops personally, but might I hazard a guess that you flare it manually? My gut instinct is you'll touch down during a go around initiated from c20', and given that the autoland light hasn't illuminated at this point I'd assume the flight path is reasonably stable anyway, so is raising the nose a couple of degrees an option? A baulked landing could also be initiated subsequently I guess. Just by tuppence worth.

davar laad
yes the alert height is aircraft specific in quantity (the number of ft) not in quality (the arlet height concept whcih is linked to catIII b operations whic requires a fail operational system displayed on FMA by catIII dual)

dunbar,
you flare manually if you have sufficient visual reference otherwise you go around. it is valid for CAT III a & b

For European operations, Alert Height is described in CS AWO. With recent transatlantic harmonization of requirements, I would expect the FAA interpretation to be similar, or approve the manufacturer’s recommended operation.

CS-AWO 312:- For a fail-operational system with a decision height below 15 m (50 ft) or with no decision height, an alert height must be established in accordance with CS–AWO 365(a) and must be at least 30 m (100 ft). Max alert height should not be greater than 300ft.

Concept, CS-AWO 300:- The alert height is a specified radio height, based on the characteristics of the aeroplane and its fail-operational landing system. In operational use, if a failure occurred above the alert height in one of the required redundant operational systems in the aeroplane (including, where appropriate, ground roll guidance and the reversionary mode in a hybrid system), the approach would be discontinued and a go-around executed unless reversion to a higher decision height is possible. If a failure in one of the required redundant operational systems occurred below the alert height, it would be ignored and the approach continued.

Thus the question of the failure of FLARE at 30 ft should not occur (reliability 10-9?).

As most fail-operational certifications are aircraft specific, it might be expected that the alert height and crew procedures are also type related. Thus, aligning procedures with other aircraft types might be unwise. However, a change or deletion of a call might be approved by a national authority provided the procedures before and after alert height are clearly understood and meet the basis of the aircraft certification. Any change would be a function of training and SOP, however all changes should be verified by the manufacturer to check that nothing essential has been overlooked.

The term is also mentioned in JAR-OPS 1 Subpart E under ‘Fail-Operational flight control System’ (as CS AWO 300);training requirements are stated.

Alert height is a design criteria.

100' for a320

200 for a330

On the line you can take it that above alert height as fail passive and below as fail operational

Don't get all horny about it

Just understand your company callouts and make them.

V

Nocti,

What I'm saying is that our company SOP's do not make use of the Airbus Alert Height. We do not continue with an autoland in LVP's in the event of any failure below 1000', therefore the alert height is irrelevant. The only exception to this is if RVR > cat 1 and visual with the runway.

Spin Doctor,

There are always operators who do things differently to the manufacturers recommendations and procedures - generally instigated by small minded managers who think they know better.

I've seen a lot of it in the last 25 years, and some real beauties. One outfit I worked for had their own single engined NPA procedure in place for many years before the manufacturer found out and told them that a go-around would not meet the minimum climb gradient required.

Airbus have, in accordance with JAA and EASA criteria, published an Alert Height for use with All Weather Operations. For an operator to ignore the importance of this is either borne out of ignorance or arrogance.

Stupid question from a naive person
 

this has nothing to do with the subject matter but i am unsure who better to ask...I have recently become an operations controller for a handling agent and have listened to atc/radar/approach etc and am puzzled as to what the phrase "zulu" or other such phoenetic phrases is current or when pilots say when they are inbound that information "lima" etc..... yes I knowI appear thick but would just love to know what I am listening to.


Many thanks for your help

CDC