Flight instructor reported a near miss with a private jet while conducting a practice GPS approach.

Narrative:

With student on board on practice GPS approach we experienced a near miss of a private jet. After departure we headed east with the intention of conducting practice vectors for the GPS approach. Very shortly after departing we began to monitor unicom as we flew east and set up the approach. I had my student intercept the approach course just outside of the final approach fix and told him to make an announcement on the unicom that we were 6 miles out on the GPS xy approach. We then continued on; hearing no other traffic. We intercepted the glideslope and began down. At 3 miles out; I had the student make a second announcement of our position. At that time; the traffic alert sounded showing an aircraft less than 1 mile directly behind us and under us by 100 feet. I looked for the traffic on both sides as well as behind us and my student stopped descending on the glideslope. As I looked back at the GPS traffic it had gone to zero at which point a private jet passed us on the left side of the aircraft less than 50 feet under us with no lateral separation. We executed a go around and we watched the jet land. I confirmed the radio frequency and volume. I then attempted to call the aircraft; twice and received no reply. I then called the FBO who answered right away and did a radio check. The FBO then called the jet taxing to the ramp that answered only after several calls.

Original NASA ASRS Text

Title: Flight Instructor reported a near miss with a private jet while conducting a practice GPS approach.

Narrative: With student on board on practice GPS approach we experienced a near miss of a private jet. After departure we headed east with the intention of conducting practice vectors for the GPS approach. Very shortly after departing we began to monitor Unicom as we flew east and set up the approach. I had my student intercept the approach course just outside of the final approach fix and told him to make an announcement on the Unicom that we were 6 miles out on the GPS XY Approach. We then continued on; hearing no other traffic. We intercepted the glideslope and began down. At 3 miles out; I had the student make a second announcement of our position. At that time; the traffic alert sounded showing an aircraft less than 1 mile directly behind us and under us by 100 feet. I looked for the traffic on both sides as well as behind us and my student stopped descending on the glideslope. As I looked back at the GPS Traffic it had gone to zero at which point a private jet passed us on the left side of the aircraft less than 50 feet under us with no lateral separation. We executed a go around and we watched the jet land. I confirmed the radio frequency and volume. I then attempted to call the aircraft; twice and received no reply. I then called the FBO who answered right away and did a radio check. The FBO then called the jet taxing to the ramp that answered only after several calls.

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.

Attributes
ACN	1392461
Time
Date	201609
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Flight Plan	None
Aircraft 2
Make Model Name	Light Transport
Flight Phase	Final Approach
Person 1
Function	Instructor
Qualification	Flight Crew Commercial Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 3000 Flight Crew Type 1500
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 50 Vertical 0