Controller’s Expectation That VW02 Would Have Departed Sooner Led To An Inadequate Scan And Loss Of Situational Awareness

Location: North Las Vegas, Nevada Incident Number: OPS24LA011
Date & Time: December 9, 2023, 11:06 Local Registration: N857PA (A1); N744AF (A2)
Aircraft: Diamond Aircraft Ind Inc DA20-C1 (A1); Robinson Helicopter R44 (A2) Aircraft Damage: None (A1); None (A2)
Defining Event: Near midair/TCAS alert/loss of separation Injuries: 2 None (A1); 1 None (A2)
Flight Conducted Under: Unknown (A1); Unknown (A2)

Analysis: A Robinson R-44 helicopter N744AF, VW02 (View 02), and a Diamond DA20-C1 Eclipse, N857PA were involved in a near midair collision (NMAC) approximately 1.7 miles west of the North Las Vegas Airport (VGT).

At the time of the incident the VGT airport traffic control tower (ATCT) was staffed by two controllers with three personnel available. The local control 1 (LC1), local control 2 (LC2), local assist (LA1), and controller in charge (CIC) positions were all combined to the LC1 position. 

The ground control (GC), flight data (FD), and clearance delivery (CD) positions were combined at the GC position. According to ATC audio recordings and post event interviews, the LC1 controller had instructed N857PA to enter left traffic for runway 30L. About 25 seconds later, VW02 requested a west departure from the transient ramp and the LC1 controller advised departure would be at their own risk. About three minutes later, VW02 and N857PA experienced a NMAC after VW02 had departed to the west and N857PA was on a southeast heading, approaching the mid-field left downwind position for runway 30L.The LC1 controller’s expectation that VW02 would have departed sooner led to an inadequate scan and loss of situational awareness. Additionally, the LC1 controller did not provide adequate or timely traffic advisory or safety alert information to either aircraft as required in FAA Order JO 7110.65AA, Air Traffic Control.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this incident to be -- The local controller’s loss of situational awareness, inadequate provision of traffic advisory or safety alert information, and lack of positive control, that resulted in a near-midair collision.

FMI: www.ntsb.gov