A tower controller reported a departure flew off course into confliction with arriving traffic. The ...

Narrative:

Aircraft X departed an assigned heading of 010 because of inbound traffic; aircraft Y; on a visual approach. Once airborne; aircraft X; had an inoperable transponder and was not being track by the primary radar. The tower controller had aircraft X in sight and noticed that although a 010 heading was give for departure; and a read back from the pilot was assured; aircraft X appeared to be heading toward the incoming [aircraft] on a visual approach. The tower controller immediately verified with aircraft X that he should be heading 010 and the pilot apologized and began correcting; while trying to recycle his transponder. Once it was known that the transponder was actually inoperative; and the primary radar was not picking him up; he was then instructed to join a VOR radial and contact departure. Traffic was then given to aircraft Y who reported the aircraft X in sight and was instructed to maintain visual separation. About 7 miles north of the airport at a reported altitude of 3;000 feet a primary target was observed. When aircraft X checked on I was about to make radar contact by position correlation then gave traffic to aircraft X about aircraft Y. About 13 miles north of the airport aircraft X's transponder began transmitting and altitude was verified. The problem here is that the primary radar has known issues of not picking up targets. It's been worked on and called back into service multiple times. It is usually not an issue; but this scenario is exactly why it is dangerous. The weather was clear; but if it wasn't and tower; or aircraft Y didn't have aircraft X in sight a loss could have occurred and possibly an accident. Aircraft Y's TCAS would not have picked up aircraft X because of the inoperable transponder. Our ASR8 radar needs to be replaced and upgraded.

Original NASA ASRS Text

Title: A Tower Controller reported a departure flew off course into confliction with arriving traffic. The Controller reported known poor radar coverage impeded their ability to notice the aircraft off course and resolve the confliction.

Narrative: Aircraft X departed an assigned heading of 010 because of inbound traffic; Aircraft Y; on a Visual Approach. Once airborne; Aircraft X; had an inoperable transponder and was not being track by the primary radar. The Tower Controller had Aircraft X in sight and noticed that although a 010 heading was give for departure; and a read back from the pilot was assured; Aircraft X appeared to be heading toward the incoming [aircraft] on a Visual Approach. The Tower Controller immediately verified with Aircraft X that he should be heading 010 and the pilot apologized and began correcting; while trying to recycle his transponder. Once it was known that the transponder was actually inoperative; and the primary radar was not picking him up; he was then instructed to join a VOR radial and contact departure. Traffic was then given to Aircraft Y who reported the Aircraft X in sight and was instructed to maintain visual separation. About 7 miles north of the airport at a reported altitude of 3;000 feet a primary target was observed. When Aircraft X checked on I was about to make radar contact by position correlation then gave traffic to Aircraft X about Aircraft Y. About 13 miles north of the airport Aircraft X's transponder began transmitting and altitude was verified. The problem here is that the primary RADAR has known issues of not picking up targets. It's been worked on and called back into service multiple times. It is usually not an issue; but this scenario is exactly why it is dangerous. The weather was clear; but if it wasn't and tower; or Aircraft Y didn't have Aircraft X in sight a loss could have occurred and possibly an accident. Aircraft Y's TCAS would not have picked up Aircraft X because of the inoperable transponder. Our ASR8 Radar needs to be replaced and upgraded.

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	1748667
Time
Date	202007
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Tower
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Shorts SD-360
Operating Under FAR Part	Part 135
Flight Phase	Initial Climb
Route In Use	Vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	B717 (Formerly MD-95)
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 1.0
Events
Anomaly	ATC Issue All Types Aircraft Equipment Problem Less Severe

A tower controller reported a departure flew off course into confliction with arriving traffic. The controller reported known poor radar coverage impeded their ability to notice the aircraft off course and resolve the confliction.