The anti-corruption watchdog had received the complaint and sent it to the chief vigilance officer, who acts as a distant arm of the CVC, for necessary action, official sources said.
It has been over six months and the Commission is yet to get any final report from the officer. The CVO may be called in to give explanation or to appear before the Commission to explain the delay, they said.
The sources declined to share further details including the name of complainant and other information on the complaint in the matter.
CBI has already registered a preliminary enquiry to probe alleged irregularities in the purchase of helicopters. The probe agency has named former Air Force chief S P Tyagi and 10 others including his cousins -- Julie, Docsa and Sandeep Tyagi -- in its preliminary enquiry.
The Commission is following up the matter with the Defence Ministry to ensure speedy conclusion of the complaint sent to its CVO in the VVIP chopper deal, they said.