Two Repairman Technicians report about a Cessna C-414A aircraft that departed with one end of static line for the Captain's altimeter not reconnected after installation of a Garmin GNS-430W Glideslope and Glideslope Indicator. Pilot returned to airport one hour and fifty minutes later in emergency situation.
Synopsis
Two Repairman Technicians report about a Cessna C-414A aircraft that departed with one end of static line for the Captain's altimeter not reconnected after installation of a Garmin GNS-430W Glideslope and Glideslope Indicator. Pilot returned to airport one hour and fifty minutes later in emergency situation.
Narrative
Disassembling an instrument panel to prep for installing a Garmin GNS-430W WAAS IFR GPS/Glideslope; GIl06A (Glideslope Indicator) and moving other instruments in the panel I removed the static line from the airspeed indicator. I did not mark or make note of the static line being removed. At the time of the removal I figured I would be doing a Static Leak Check while running the system up in altitude to check the Gray Code for the GNS 430W. Three days had passed and I started assembling the panel forgetting the static line connection. This was the last day of the install and I was feeling pressure to get it done; the pressure being the pilot standing outside the aircraft for the last three hours of the job. During testing we had other unrelated problems with the autopilot causing more delays. We finally finished with all the work running several hours behind schedule and forgetting to check the Gray Code for the GNS430W. At this time checking the GNS-430W would have been the only thing that would have caught the oversight of the static line. I had another individual check my work but there was no way they could see the static line. I was the only person who knew the line was off. We turned the aircraft over to the pilot and went home. Some time that evening I remembered the static line and called Mechanic Y. I left a message that I had left the [static] line off. At this time I was considering calling the airport to see if there was any way to contact the pilot and tell him not to pressurize the aircraft. While this was going through my head; Mechanic Y called me back and said the pilot was on the ground safely at ZZZ airport and asked if I would fix the problem in the morning. The next morning I went to work and removed the glare shield; reconnected the static line and perform a Static Leak Check. I also checked the Gray Code for the GNS430W and looked every thing else over several more times. I told Mechanic Y; I was happy with the aircraft at this time and went home. A few days later in the morning; we all got together and talked about what had happened and what we could do so that it would never happen again.
Second reporter narrative
Old equipment was removed and a new Garmin GNS-430W WAAS IFR GPS/Glideslope was installed in the Cessna-4l4A. The Pitot/Static System had not previously been opened during the installation and we had not planned a Static System Leak Check. During reassembly of the pilot's panel; it was necessary to disconnect one end of a static line that connects the static side of the pilot's airspeed with the altimeter. The line was not removed from the aircraft but stayed in its relative position. The glare shield was reinstalled and the line was inadvertently left disconnected. The pilot elected to leave and departed in night IMC conditions. Because the aircraft is pressurized; immediately at liftoff the airspeed read zero and the altimeter was unusable and most likely matched cabin altitude. The aircraft was airborne for approximately one hour and fifty minutes; during which time the pilot declared an emergency and was unable to determine his altitude. He did not depressurize the aircraft. At some point he determined the co-pilot panel instruments were usable and following two failed approaches; landed on the third attempt. As a result we have begun attaching a red plastic streamer to pitot/static lines when disconnected.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.