The Aircraft and Owner

The Piper PA-31 350 Navaho Chieftain is generally a working aircraft, and this one is used for aerial photography. Peregrine Aerial Surveys, based at Abbotsford Airport, flies the Navajo as a platform for a large format, high resolution mapping camera. The camera, a DMCII-230 by Zeiss Intergraph, has 230 megapixels in black and white, and another 126 megapixels in colour. It is the first of its kind in Canada, and only the second in North America. The camera is used to generate stereo images, contour maps, digital terrain models, and interpreted images.

The Need

The primary need was to get rid of and replace the aircraft’s aging and increasingly costly to maintain gyro-based HSI system.

The Maxcraft Solution

Electronic HSI systems provide value to aircraft owners and fleet operators by eliminating recurring costs of overhauling aging mechanical gyros. Peregrine had the following completed for their aircraft

• ASPEN 1000C3 (Electronic HSI) install
• GTN 650 (GPS/NAV/COM) install
• aera 796 panel dock
• 2-year re-cert on Pitot Static
• MH pulse oxygen installation

The Story

Project planning and design was completed as per the initial quote. Major equipment was issued and the interior removed. Work began on the panel when we removed the #1 Nav/Com, gyro system with HSI, ADF indicator, and pilot side Turn & Bank indicator. With these removals the panel would soon accommodate the ASPEN & GTN.

We installed the ASPEN 1000 C3 (with ACU 2 for ADF) which meets the Level B software assurance levels required for FAR Part 23 Class III aircraft. Along with this install, we moved the standby attitude indicator to the left of the Aspen. The GTN 650 was also installed with functions testing serviceable. We then channeled the DME to Nav1 of the GTN650 for full integration and a reduction of pilot work-load. A center instrument panel was fabricated from scratch as per the original aircraft drawings and installed. The Garmin aera 796 handheld was panel mounted vertically for panel power and xm weather connectivity.

A jumper was wired onto the GTX 327 transponder so it turns on when the avionics master is switched on. In addition, the transponder was coupled to the GTN 650 for an ‘auto-activate’ feature where the transponder utilizes GPS to select the ‘On Position’ automatically during take-off or at about 30kts. The transponder conversely switches to standby position on touch-down (below 30 kts). Maxcraft also cleaned up some ugly wiring discovered behind the left-hand circuit-breaker panel. This is where we had found a few burnt wires, 14 circuit-breaker screws that were touching, improper wire routing, and some wires which were found to be the wrong size. However, all issues were rectified.

Following hardware installations an autopilot functional test was carried out relating to the Aspen & GTN autopilot systems which were deemed serviceable. Additional tests were carried out for a two year re-cert on the pitot/static system. For this recertification our tasks included an Altimeter Calibration, Encoder Calibration, Transponder Calibration, as well as an Inspection and Test of the Static System.