PPRuNe Forums - Smart 500 Callout

PPRuNe Forums (https://www.pprune.org/)

- Tech Log (https://www.pprune.org/tech-log-15/)

- - Smart 500 Callout (https://www.pprune.org/tech-log/509460-smart-500-callout.html)

Smart 500 Callout

After trawling all my manuals and the internet, I failed to find definitive information on the Smart 500 Callout on the 747-400.

An earlier PPRuNe message included this information:

Quote:

"According to the Flight Manual Supplement for the MKVIII EGPWS System Installation ATR 42 & 72.

To meet the AC’s for installation of EGPWS onto any aircraft there
must be a form of callout for 500 ft. This can be acheived via one
of three options in the EGPWS, as a “Hard 500”, “Smart 500”, or
“500 Above Field” callout. These are included as options in the
Callout Menu items. There are also menus without 500 foot callouts,
these are included for aircraft that already have the means
to announce 500 ft.

1) The “Hard 500” foot callout will annunciate “FIVE HUNDRED” once during each approach.

2) The “Smart 500” foot callout, when selected, will assist pilots during
a non-precision approach by enunciating “FIVE HUNDRED”
feet in addition to any other altitude callout discussed above. The
EGPWS determines a non-precision approach when Glideslope
is greater than 2 dots deviation (valid or not) or a back-course
approach is detected.

3) The “500 Above Field “ callout will be annunciated once during
each approach when the aircraft flies below 500 ft above the landing
field. It compares the GPS-based geometric altitude with the
closest runway. The callout may be optionally chosen to
annunciate “FIVE HUNDRED” or “FIVE HUNDRED ABOVE”."

For the "Smart 500" callout, I don't see what sources are used as a reference or whether it's barometric or radio altimeter-derived. I assume it's not GPS-derived as that's what the "500 Above Field" uses.

Would it use the pilot's FMC entry of arrival airport/runway (i.e. TDZ-based)? Will it work independently of GPS and the Terrain Database in the EGPWS?
Could it be used with QFE landings? (where option fitted).

If the airport/runway is not in the airline's FMC database, will it fail to sound?

The callout on the 744 is RadAlt derived.

Thanks.

So you're saying it won't sound at 500' above airfield elevation, just 500' above the terrain?

Entirely unhelpfully, the Smart 500 on the 738 is as follows:

Smart 500 Radio Altitude Callout
The Smart 500 Callout annunciates FIVE HUNDRED during a non-ILS or
non-GLS approach. Activation of this callout is dependent only on lack of an ILS
or GLS. However, if flying an ILS or GLS approach, and there is excessive flight
path deviation, the GPWS will conclude a non-ILS or non-GLS approach is being
flown. This feature functions with or without any of the normal altitude callouts.
When descending below 500 feet radio altitude on approach, a FIVE HUNDRED
callout is given if:
• an approach other than ILS (the ILS frequency is not tuned) or GLS is
used, or
• a backcourse approach is detected, or
• Glideslope Cancel is selected, or
• the flight path is not within +/- 2 dots of a valid localizer beam (excessive
ILS or GLS flightpath deviation), or
• the flight path is not within +/- 2 dots of a valid glideslope (excessive ILS
or GLS flightpath deviation)

Given it comes from the EGPWS, I assume it works based on the software in there, which would probably be the same version across different types depending on different operator options and specs.

Thanks, gents.

Descriptions of Smart mode in other Honeywell boxes seems to agree. Always Rad Alt (unless we are talking about the GPS-based callout).

The 2,500' 1,000' 500' 40' 20' and 10' callouts all work off RA1 and will work irrespective of the type of approach being conducted.

At least in CX Aircraft anyway....

From the A330 FCOM 1

AUTOMATIC CALL OUT

FWC generates synthetic voice for radio height announcement below 2500 feet. These announcements come through the cockpit loudspeakers even if the speakers are turned off.

PREDETERMINED CALL OUTS:-

callout:-
2500 "TWO THOUSAND FIVE HUNDRED"
500 "FIVE HUNDRED"
40 "FORTY"
20 "TWENTY"
10 "TEN"
DH (or MDA/MDH) + 100 "HUNDRED ABOVE"
DH (or MDA/MDH) "MINIMUM"

Note : The reference altitude for the +100 and Minimum call outs is the radio altitude for precision approaches (DH) and baro altitude (MDA/MDH) for non precision approaches.

Pin programming allows the operator to select the callouts needed. If aircraft remains at a height that is in the detection zone for a height callout, the corresponding message is repeated at regular intervals.

'Smart', yeah, errm, well not really.

As I understand it, the point of the 500' call is the final stabilized gate check for VMC, so the call is AAL and hence baro not rad alt. I went to Addis once and had to make the call verbally at around 800' rad alt only to get a second auto call out a little while later.

Also, why is the auto call out only for non-prec approaches? When doing an ILS it is silent, just the 1000' call (again rad alt but should be AAL baro).

Not on our Aircraft, ours are RAD ALT and always work.

Quote:

At least in CX Aircraft anyway....

Well, the "Smart 500", is one of 3 options. Cathay seems not to have it.

You can probably tell that the aircraft hasn't got a hard 500' callout by doing an EGPWS Confidence or CMC Test. The tests run through all of the callouts. If the aircraft, for example, has the Smart 500' callout, it won't be sequence with the other callouts.

The Smart callout doesn't seem to be as smart as the "500 above field" callout, which is based on GPS height above the runway (which, in a sense, is baro height without the knob twiddling).