November 10, 2011 - A recent operating system update for Apple's immensely popular iPad tablet computer left many pilots dismayed to learn they were missing some very important files and applications, and that doesn’t include "Angry Birds." 

Within days after Apple released its iOS 5 update on October 12, several pilots with aeronautical charts and other flight information downloaded onto their iPads discovered some of those files were missing, without any notice or explanation. This was due to a new “clean-up” function included with iOS 5, intended to free up valuable system memory by deleting cached directory files.  

Many aviation applications for the iPad store charts and other data within those files. The “clean-up” function worked completely behind the scenes, without any indication of what files were removed until users attempted to access them. 

In addition to pilots caught unaware by that change, the news also surprised many developers of aeronautical applications. Hilton Goldstein, developer of WingX Pro software for pilots, said he learned of the issue the same way most pilots did, "by browsing the Web." He added that Apple did not advise developers or users of the change. 

Fortunately, on November 2, Apple announced that a fix is coming to resolve the error. "[The 'clean-up' issue] will be resolved in the new 5.0.1 release, but app developers will need to specifically modify their code to mark files to not be deleted," Goldstein noted. "We have already modified the code for the planned November release of WingX Pro7 so that our databases will not be deleted by iOS 5." 

Rick Ellerbroch, Director of Strategy for Jeppesen, said his company discussed the file deletion problem with Apple as soon as it was discovered, "and [Apple] was quite responsive," he noted. "We think it is encouraging there is now a path forward to resolve the issue.” 

The “clean-up” problem prompted at least one operator to reexamine how they used iPads in cockpits, and to keep a cautionary eye towards potential issues in the future. A spokesperson with CitationAir by Cessna stated news of the iOS 5 clean-up issue led to a relatively minor, but important, operational change for that outfit.

“We heard about the potential problems at NBAA2011, and are now working closely with Jeppesen on a patch before we download the new operating system,” said the spokesperson. “As a result of this, we have also implemented a new policy and procedure to prevent any new operating system downloads prior to a thorough test and approval.”