There are cases where a Maintenance Organisation is allowed to use old revision of maintenance data during the maintenance works. However in such a case, some conditions must be fulfilled. This article explains when the use of up to dated maintenance data is mandatory and when it is instead possible to use older revision of the manuals.
The HF antenna for long range communications makes the HF system capable of communicating over distances of 3000 km or more. Here explained why the HF coupler is filled with low pressure nitrogen gas.
This article explains what a Maintenance Planning Document is, where it is coming from, what it is used for and what its relationship with the Aircraft Maintenance Program is.