C172 flight instructor reported a near midair collision with an air carrier flight.

Attributes
ACN	1556595
Time
Date	201807
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Other local
Flight Plan	None
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Commercial
Experience	Flight Crew Last 90 Days 180 Flight Crew Total 1000 Flight Crew Type 1000
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 0 Vertical 400

Narrative:

C172 departed ZZZ and cleared right turnout to the north. Exited the class D and tower approved frequency change. Monitored [local] approach. Working with a student; planned to go out a few miles practice climbs; descents; and turns before returning to ZZZ for pattern practice. Heard a traffic advisory to an airliner that an aircraft was 8 northwest of ZZZ with altitude (unverified) and direction of flight (that aircraft was us). We did not have the airliner in sight. That was the only advisory given on ATC approach frequency and then that airliner was switched to ZZZ tower on a visual approach. A few minutes later ATC made a blind call on the approach frequency to our aircraft callsign. We responded and they informed us an airliner was 'rerouted' around us. They gave an updated position of the airliner. The airliner landed without further incident. After completing the flight; had a discussion with tower personnel and they reported that the airliner reported us descending at 400 feet above them at the time being 'rerouted.'

Original NASA ASRS Text

Title: C172 flight instructor reported a NMAC with an air carrier flight.

Narrative: C172 departed ZZZ and cleared right turnout to the North. Exited the Class D and tower approved frequency change. Monitored [local] approach. Working with a student; planned to go out a few miles practice climbs; descents; and turns before returning to ZZZ for pattern practice. Heard a traffic advisory to an airliner that an aircraft was 8 NW of ZZZ with altitude (unverified) and direction of flight (that aircraft was us). We did not have the airliner in sight. That was the only advisory given on ATC approach frequency and then that airliner was switched to ZZZ Tower on a visual approach. A few minutes later ATC made a blind call on the approach frequency to our aircraft callsign. We responded and they informed us an airliner was 'rerouted' around us. They gave an updated position of the airliner. The airliner landed without further incident. After completing the flight; had a discussion with tower personnel and they reported that the airliner reported us descending at 400 feet above them at the time being 'rerouted.'

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.