Narrative:

I was flying a glider today and launched from ZZZ. ZZZ is located under the outer shelf of the ZZZ1 class B airspace. I am well aware of this airspace as a regular pilot at ZZZ (glider and sel airplanes typically) and have been based here for 10+ years. Today I was attempting to climb in the glider (using thermals / rising air currents and no engine or other power source) to almost the base of the class B (3500 feet MSL) and then use the altitude to cruise northwest out of the bravo lateral boundaries before climbing higher. I rely on my installed electric/gps-based glide computer to help me avoid the bravo lateral confines as it has a very accurate moving map display and provides audible 'airspace warning' alerts. I had made a few climbs and stopped by 3400 feet MSL to avoid the 3500 feet bravo base and headed west. My flight computer showed me outside of the bravo lateral limits so I continued a climb at some point. As I was passing 4000 or 4100 feet while climbing in circles (thermalling) I noticed that the map on my glide computer was not moving like it usually does when I circle. (As I try to keep my eyes outside for traffic; I listen to my 'audio variometer' to judge my climb speed and the glide computer gives verbal airspace alerts when I approach the bravo or other airspace usually. So I do not glance inside the cockpit at the glide computer very often when thermalling/climbing.) I checked the status screen on the flight computer and realized it had no GPS location lock. I knew I was close to the edge of the bravo from visual references but I thought I was still northwest of the lateral boundary. I opened my 'backup' flight computer on my iphone which uses the iphone built-in GPS and realized I was inside the outer shelf of the bravo at about 4000 MSL. Oh no! I immediately turned west and made a direct run out of the bravo as soon as I realized this. I continued my flight relying on my backup (iphone) glide computer and never did get a GPS signal on my primary installed glide computer for the rest of this flight. When I landed; I opened the back of the instrument panel and discovered my problem - the GPS antenna wire had vibrated loose and fallen out of the port in the glide computer. I plugged it back in; screwed it tight and tested the glide computer to determine that I now had a working GPS signal. Unfortunately this event occurred because of my over-reliance on the installed GPS technology to keep me out of the bravo airspace instead of good old fashioned pilotage using landmarks. Contributing to this was the fact that the glide computer does not provide any sort of 'GPS lost' alert (audible or visual) and the fact that I was concentrating on circling/climbing and not glancing at the computer very often; which I should have done since I knew I was near the bravo and there was a westerly wind aloft (5-7 knots) that was likely blowing me towards the bravo as I circled. Finally; I could have also had my backup iphone computer/position alerts working as a double-check while I was close to the bravo airspace. In the future; I will glance at the installed map once every circle when climbing or operating near controlled airspace to make sure I have a valid GPS signal. I will also have my backup iphone computer activated during flight near/under bravo airspace as a double check. Finally; I will rely more on landmarks to make sure I remain clear of the airspace whenever near the vertical limits of it.

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Original NASA ASRS Text

Title: Mini-LAK Glider pilot reported a malfunction with the electronic flight bag and loss of the GPS signal. Glider pilot reported inadvertent Class B Airspace penetration.

Narrative: I was flying a glider today and launched from ZZZ. ZZZ is located under the outer shelf of the ZZZ1 Class B airspace. I am well aware of this airspace as a regular pilot at ZZZ (glider and SEL airplanes typically) and have been based here for 10+ years. Today I was attempting to climb in the glider (using thermals / rising air currents and no engine or other power source) to almost the base of the Class B (3500 feet MSL) and then use the altitude to cruise NW out of the Bravo lateral boundaries before climbing higher. I rely on my installed electric/gps-based glide computer to help me avoid the Bravo lateral confines as it has a very accurate moving map display and provides audible 'airspace warning' alerts. I had made a few climbs and stopped by 3400 feet MSL to avoid the 3500 feet Bravo base and headed west. My flight computer showed me outside of the Bravo lateral limits so I continued a climb at some point. As I was passing 4000 or 4100 feet while climbing in circles (thermalling) I noticed that the map on my glide computer was not moving like it usually does when I circle. (As I try to keep my eyes outside for traffic; I listen to my 'audio variometer' to judge my climb speed and the glide computer gives verbal airspace alerts when I approach the Bravo or other airspace usually. So I do not glance inside the cockpit at the glide computer very often when thermalling/climbing.) I checked the status screen on the flight computer and realized it had no GPS location lock. I knew I was close to the edge of the Bravo from visual references but I thought I was still NW of the lateral boundary. I opened my 'backup' flight computer on my iPhone which uses the iPhone built-in GPS and realized I was inside the outer shelf of the Bravo at about 4000 MSL. Oh no! I immediately turned west and made a direct run out of the Bravo as soon as I realized this. I continued my flight relying on my backup (iPhone) glide computer and never did get a GPS signal on my primary installed glide computer for the rest of this flight. When I landed; I opened the back of the instrument panel and discovered my problem - the GPS antenna wire had vibrated loose and fallen out of the port in the glide computer. I plugged it back in; screwed it tight and tested the glide computer to determine that I now had a working GPS signal. Unfortunately this event occurred because of my over-reliance on the installed GPS technology to keep me out of the Bravo airspace instead of good old fashioned pilotage using landmarks. Contributing to this was the fact that the glide computer does not provide any sort of 'GPS Lost' alert (audible or visual) and the fact that I was concentrating on circling/climbing and not glancing at the computer very often; which I should have done since I knew I was near the Bravo and there was a westerly wind aloft (5-7 knots) that was likely blowing me towards the Bravo as I circled. Finally; I could have also had my backup iPhone computer/position alerts working as a double-check while I was close to the Bravo airspace. In the future; I will glance at the installed map once every circle when climbing or operating near controlled airspace to make sure I have a valid GPS signal. I will also have my backup iPhone computer activated during flight near/under Bravo airspace as a double check. Finally; I will rely more on landmarks to make sure I remain clear of the airspace whenever near the vertical limits of it.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.