On November 12, 1996, Kazakhstan Airlines Flight 1907 and Saudi Arabian Airlines Flight 763 collided mid-air approximately 40 miles west of Delhi in Haryana, India. The accident occurred when the Kazakhstan IL-76 aircraft was on a non-scheduled flight from Chimkent in Kazakhstan on route to Delhi and the Saudi Boeing 747 aircraft was on a scheduled passenger flight from Delhi to Dahran.
After the Saudi aircraft’s take off from Delhi, they were instructed by Delhi Approach to ascend and maintain a flight level (FL) of 14,000 feet. Delhi Approach instructed the Kazakhstan aircraft to descend and maintain a FL of 15,000 feet. At 6:40pm, the two aircrafts blips on the radar screen disappeared, as both aircrafts collided. There were no survivors from the wreckage of either aircraft; all 349 persons aboard - 312 occupants of the Saudi aircraft and 37 occupants of the Kazakhstan aircraft - died as a result of the collision.
Role of Key Actors:
The Saudi Arabian Airlines flight crew followed all ATC instructions at the time.
The Kazakhstan flight crew did not follow all ATC instructions at the time.
Air Traffic Controllers instructions were clear and proper
Timeline of events (includes latent issues that underpin accident):
Civil/Military ATC Coordination:
System suffers serious shortcomings, adversely affecting air safety in India
Civil and Military ATC proficiency standards inconsistent
Organisational set-up of DGCA (India):
No ATC element to oversee ATC aspects which presently fall under purview of Airports Authority of India
One-man accident/incident prevention cell inadequate
Organisational set-up of AAI:
Highest post for an ATC professional of Executive Director (Air Traffic Management) inadequate
ATC:
Primary surveillance radar only installed (no SSR available at Delhi airport)
Profession lacking recognition and status it deserves
Working conditions not desirable; working space (especially Area/Approach Control, ATC Simulator and IAF) and number of work-stations inadequate
No system of licencing air traffic controllers (In India)
Airspace:
Single air corridor (not uni-directional)
Commercial air corridor narrowed due to coexisting with Indian Air Force airspace
Indian Air Force reluctant to open more civil aviation airspace
Both Aircraft:
Neither aircraft installed with TCAS/ACAS
Kazak Aircraft:
Altitude parameter accuracy limits installed (regarding FDR) were not in accordance with ICAO Annex 6
Did not have Altitude Alert System or Altitude Acquisition System installed
Had not established direct pilot-controller communication
Both Aircraft:
Entered cloud layer resulting in reduced visibility
Why it happened:
Physical factors:
Kazak aircraft descended below assigned FL 150 to unauthorised FL 140 (root cause)
Human factors that contributed to the unauthorised descent:
Kazak Pilot: Inadequate English language skills (wrong interpretation of ATC instructions)
Kazak Pilot: Poor airmanship and lack of Crew Resource Management (CRM) skill together with poor leadership qualities
Kazak flight crew: Casual attitude and lack of coordination in the performance of their respective duties
Kazak flight crew: A lack of standard callouts
-