Display the differential pressure and relative altitude of a pressurised aircraft

Available on App Store


The only app that displays pressurization information

3 Cockpit designs

PIPER: turboprop aircrafts (5.5 PSI ΔP)
CITATION: biz jets (9.0 PSI ΔP)
BOEING: jet airliners (9.1 PSI ΔP)

Differential pressure

This instrument displays the difference between the air pressure inside and outside the aircraft in PSI.

Cabin altitude

This instrument displays the relative altitude inside the cabin of the aircraft in thousand feet.

Master warning

An alarm goes off in case of cabin over pressure or high cabin altitude (above 14,000 feet).


Displays the rate of climb or descent inside the cabin of the aircraft.

Flight level

Displays the aircraft's flying altitude. Eg. A flight level of 390 means a flying altitude of 39,000 feet.

What is cabin pressurization

Cabin pressurization is used to create a safe environment on board of aircraft flying at high altitudes (generally above 12,500 feet). Compressed air is generally pumped from the engines' bleed air into the cabin trough an environmental control system. The cabin pressure is regulated by an outflow valve that opens and closes to increase, decrease or hold a certain air pressure inside the cabin.
Pressurization becomes necessary at altitudes above 14,000 feet (4,300 m) above sea level to protect crew and passengers from the risk of a number of physiological problems caused by the low outside air pressure above that altitude. It also serves to generally increase passenger comfort.

Example: a plane flying at an altitude of 25,000 feet with a cabin differential pressure of 5 PSI will provide a cabin altitude of 9,100 feet while a plane flying at the same altitude but with a cabin differential pressure of 6 PSI will provide a more comfortable cabin altitude of 6,700 feet.

Version review

1.0 - May 2015
Initial version

1.1 - May 2015
Introduced two new cockpit designs: Citation and Boeing
Added a Master caution alarm and button
Improved the variometer's stability
Minor settings improvements
Bugs fixed

1.2 - June 2015
Bugs fixed
Added a help guide
New icon

1.3 - Agoust 2015
New cockpit style: Airbus (max 8.6 ΔP)
Added a speed indicator (ground speed)
Added a Mach indicator
Bugs fixed


  • This application works only on the iPhone6 and iPhone6+
  • The phone has to be out of airplane mode
  • A good GPS signal is necessary for the app the work correctly. Place your iPhone in a position where you get a clear view of the sky, preferably close to a window. It can take up to 10 minutes to receive a good signal

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