The DGCA's unprecedented move came after the regulator's team found that several flights operated by GMR Aviation in the last month, including one on Monday when an aircraft flew Congress Vice President Rahul Gandhi to Bhubaneshwar, had skipped some mandatory tests, DGCA sources said.
The tests included the pre-flight breath analysis of pilots and cabin crew, with the breathalyser equipment being non-functional, they said.
The non-scheduled charter operator's documentation and equipment were monitored between March 12 and April 14 and these major lapses were found by the regulator.
After going through the flying records of GMR Aviation during this period, DGCA found evidence of "false" pre-flight medical checks, the sources claimed.
GMR's Falcon 2000-Lx, one of the most advanced business jets in the country which flew Rahul on Monday, is used extensively by the Gandhis, who also use its Hawker-750 airplane and two Bell choppers.
The DGCA issued notices to the 11 pilots and six cabin crew of GMR Aviation as to why their should not be suspended for five years, they said.
The regulator also decided to act against the company's doctor for issuing pre-flight medical certificates to the crew even when the breathalyser equipment was not working for almost a month, the sources said.
Pre-flight breathalyser tests are mandatory for all flights which are used by SPG-protectees like Rahul or Sonia Gandhi.