Backup Baro Altimeter

[Jerry 5TJ]

For many years I kept a second barometric altimeter in the panel of my "E" model just as backup.

I'd scan both dials during approaches to make sure they agreed:  50 year old mechanical instruments have been known to fail.

 

More recently I changed my practice to glance at the GPS altitude on the panel mounted WAAS box, and/or the iPad.  GPS altitude is not a substitute for baro altitude, but it does give a pretty good cross-check of the mechanical instrument or the static system.

 

Now you can use your iPhone6 (which has a pressure sensor) and some Android devices as a baro altimeter backup.

 

Here's one example

https://itunes.apple.com/us/app/barometer-for-iphone-6-6-plus/id922859877?mt=8

of an app that works as a backup altimeter (in an unpressurized cabin), can be calibrated and can be adjusted for local altimeter setting.  

 

 

[Piloto]

The panel mounted WAAS GPS is your best source for altitude on approaches or terrain avoidance. GPS altitude is always true MSL altitude at any altitude irrelevant of barometric pressure. It differs from barometric altitude due to changes in barometric pressure. For approaches GPS altitude is more accurate. But for traffic avoidance baro altitude is the one to use since all transponder encoders use it. On instrument approaches I always cross check the baro altimeter with WAAS GPS altitude.

 

José  

[ryoder]

Radar altimeter

[Bob - S50]

Radar altimeter

Only good for flatlanders.  Won't do you much good at places with a drop off or wildly varying terrain at the end of the runway.

 

Like CVG, SEA, SEZ, GEG.  I'm sure there are others.

 

Bob

[ryoder]

My Garmin d2 watch has a baro altimeter.

[carusoam]

How is the battery life on the D2?

I have one of G's GPS watches for jogging. If I accidently leave the GPS running, it doesn't go very long...

Best regards,

-a-