Mobile flight information providers have been warning that a recent software update for the Apple iPad and other devices could cause charts and other navigation information to “disappear” from their systems. The problems are surfacing as operators have increasingly turned to the iPad for navigation and other electronic flight bag use.

FAA has approved the iPad chart use for certain phases of flight with operators such as Executive Jet Management, CitationAir and others.

Apple this month implemented its mobile operating system (iOS5) upgrade for iPads and iPhones. The new system includes a “clean-up” feature that will delete saved data when system memory becomes low. So if an operator has 1 GB of free space and downloads a 3 GB file, then the system will delete 2 GB of data from other apps to make room, navigation information provider ForeFlight says.

According to the Aircraft Owners and Pilots Association, the data is deleted with little warning and only a small “cleaning” message appearing.

The problem has been discovered not only with ForeFlight navigation apps, but others, including WingX. WingX Pro 7 developers have advised against upgrading to iOS5 until Apple has addressed the issue. While the developers maintain their system supports iOS5, they say, “You could get to the airport and find that WingX Pro 7 and/or its databases (e.g. sectionals) have just disappeared.”

ForeFlight has issued similar warnings, advising operators to “pre-flight” their iPad and iPhone before takeoff. ForeFlight says it is running a data integrity check inside the app to ensure the data is still present.

If iOS5 deletes downloaded data, ForeFlight will detail the changes. “We have contacted Apple and asked them to change this behavior in a future update,” ForeFlight says. But in the interim, ForeFlight recommends that operators ensure they have extra space on their iPad.

Jeppesen, meanwhile, also has warned its customers of potential problems. The Jeppesen Mobile FlightDeck and Mobile TC do not store application data where iOS5 can delete it.

However, Jeppesen has discovered other issues during its testing of the new software. These problems include: Some of the European VFR charts do not display properly in the Jeppesen Mobile FlightDeck terminal chart view; text cannot be entered in the search field in the Jeppesen Mobile FlightDeck, and the search field may disappear intermittently; Mobile FlightDeck may not display terrain, even though the chart filter has it selected “On” and the paste function does not work in the activation screen when the keyboard is split.

Jeppesen also is working to resolve the issues, the company notes.