Forum,
My airplane does not have an Altitude Alerter: chance to bust assigned altitudes is ever present.
I am using an app on my iPad for Altitude Alerting, which works acceptably if I succeed in keeping that App in the foreground.
Would anyone be able to advise a simple low cost hardware add-on Altitude Alerter for use in the cockpit?
Thanks.
Niner_Mike wrote:
Would anyone be able to advise a simple low cost hardware add-on Altitude Alerter for use in the cockpit?
Most GTX3xx transponders should give you ALT MONITOR that give voice alarm and warning annunciator when pressure altitude is exceeded by +250ft (seems the default value), mine rings at 2000PA under London TMA but now I have to check if this is set before departure of chnaged by my flying partners 
Ibra: yes, that’s one part of the solution. The other part is when you are cleared to let’s say FL140 and you are climbing from FL070, will you get an alert when approaching FL140? thanks
No only works in climb as you exceed level by +250ft not as you approach it, once you are on it will annuciate on +/-250ft both ways
The hack is to set assigned FL-3 in the climb, set FL+3 in the descent and your assigned level in cruise
It’s much useful to watch for airspace on top than as altitude bug
Here’s proper one:
https://shadin.com/wp-content/uploads/2020/06/IN8900AG.pdf IN8900AG local copy
I have one of those Shadin boxes and it works fine, but it is not “cheap”. I think I paid $1’000 used on eBay. Also, it only supports the RS232 connection with the Shadin altitude encoder. If one has something else (e.g. Sandia 5-35 or similar) the encoder link probably needs to be the 11-wire gray code connection which only gives 100ft resolution vs 10ft available with RS232. But it works well and is fit for purpose with alarms climbing, descending, and level deviation albeit with a fair bit of knob-twisting, incl resetting baro (e.g. altitude/FL).
chflyer wrote:
If one has something else (e.g. Sandia 5-35 or similar) the encoder link probably needs to be the 11-wire gray code connection which only gives 100ft resolution vs 10ft available with RS232.
It supports both RS232 and Grey code altitude encoders.
If you have an aircraft with a King KEA130A altimeter then you could install a KAS297 altitude alerter which also accepts the baro-scale potentiometer from the altimeter.
OK thanks guys
GI 275 has it build in…
2.2 ANNUNCIATIONS AND ALERTING FUNCTIONS
ALTITUDE ALERTING
The Altitude Alerting function provides the pilot with visual and aural alerts when
approaching or deviating from the Selected Altitude. Whenever the Selected Altitude is
changed, the Altitude Alerter is reset. The following will occur when approaching the Selected
Altitude
Yes. So does the Aspen 1000 I fly with as well: I got used to that luxury :)
