Helicopter pilot reported a near midair collision with an airliner in the vicinity of mli airport.

Attributes
ACN	1448460
Time
Date	201705
Local Time Of Day	1801-2400
Place
Locale Reference	MLI.Airport
State Reference	IL
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Helicopter
Operating Under FAR Part	Part 135
Flight Phase	Initial Climb
Route In Use	Direct
Flight Plan	VFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Single Pilot
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Commercial Flight Crew Rotorcraft
Experience	Flight Crew Last 90 Days 45 Flight Crew Total 6200 Flight Crew Type 850
Events
Anomaly	Conflict NMAC Deviation - Procedural Published Material / Policy
Miss Distance	Vertical 300

Narrative:

While taking off from a helipad and climbing to 400 to 500 feet AGL; I contacted quad city approach and received a new squawk code when the aircraft TCAS alert went off. As I was responding to quad city approach I saw an airliner fly above us. I was advised by quad city the airliner passed over us by 300 feet. I estimate we were approximately 1100 to 1200 feet MSL when we had the airliner fly 300 feet above our helicopter.radio contact with quad city approach when taking off from the helipad is best if we can get a little altitude. It is not normally in the approach path of aircraft coming into mli so it has never been a safety issue to contact ATC shortly after liftoff. The airliner must have been on quad city tower frequency and I was on quad city approach frequency.

Original NASA ASRS Text

Title: Helicopter pilot reported a NMAC with an airliner in the vicinity of MLI airport.

Narrative: While taking off from a helipad and climbing to 400 to 500 feet AGL; I contacted Quad City Approach and received a new squawk code when the aircraft TCAS alert went off. As I was responding to Quad City Approach I saw an airliner fly above us. I was advised by Quad City the airliner passed over us by 300 feet. I estimate we were approximately 1100 to 1200 feet MSL when we had the airliner fly 300 feet above our helicopter.Radio contact with Quad City approach when taking off from the helipad is best if we can get a little altitude. It is not normally in the approach path of aircraft coming into MLI so it has never been a safety issue to contact ATC shortly after liftoff. The airliner must have been on Quad City tower frequency and I was on Quad City Approach frequency.

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.