Level Busts © Global Air Training Limited 2010

Common Causal Factors  Correct readback - incorrect action  Failure to follow SID  Mis-hear  Incorrect readback by correct aircraft  Readback by incorrect aircraft  Failure to follow ATC instruction   Altimeter setting error  Aircraft technical problem  Similar confusable call signs  Poor manual handling  Level/heading confusion  Auto-pilot Problems © Global Air Training Limited 2010

Case Study Mid Air Collision  12 Nov 1996  Mid air collision between Saudia B747 and Air Kazakhstan Ilyushin 76  Air Kazakhstan Flight 1907, an Ilyushin 76 departed Chimkent, Kazakhastan for a flight to Delhi  In the meantime, a Saudi Arabian Airlines Boeing 747 had departed Delhi for a flight to Dhahran © Global Air Training Limited 2010

CVR  AK: "Good evening Passing through 230 for 180  ATC to SAA: "Maintain level 140, Standby for higher."  ATC to AK “Maintain 150. Identified traffic 12 o'clock, reciprocal Saudia Boeing 747, 14 miles. Report in sight."  AK replied by querying the distance  ATC: "Fourteen miles now"  ATC: When no reply followed he again warned "Traffic in 13 miles, level 140." © Global Air Training Limited 2010

Outcome  The Kazakh aircraft had descended below its assigned altitude and was flying at feet. A few seconds later seconds later the Ilyushin had descended another 310 feet.  Shortly afterwards both aircraft collided, with the loss of 349 lives, the world’s worst mid air collision. © Global Air Training Limited 2010

Reducing the risk of Level Busts  SIDS  Altimeter Setting  Communications  SOPs © Global Air Training Limited 2010