ALL CAPS fonts for industrial use

I'm on a plane and noticed the use of all caps on the flight crew phone:

Generally I found the phone very well designed: it has rounded colors, decent contrast, is unobtrusive for passengers, and has sensible labeling that sections content into islands and even provides nice grid alignment for the text. There are also leader lines to relate the text to the phone numbers. And the work flow is clear from top to bottom ("Lift handset" plus the arrow).

For such a thoughtful design, the one thing that stood out was the use of ALL CAPS in the labels. This makes them less readable I think.

Question:

Is there a good reason or reasons why all caps would be more usable to flight crew in this situation than title or paragraph case?