Analysis

Factual Information

Loss of Separation

Exercise 1.1.1 Read and translate the text.

The incident is described below took place in the middle of the day in the terminal area near a major European airport. The three aircraft involved were operated by major European airlines. The details of the incident have been changed to protect confidentially but the facts are very much as they happened.

AirB123 is a Boeing 737 which is intending to land at the airport and is descending to FL 100 under control of the Initial Approach Controller (INI). At 12.00, INI instructs the pilot of AirB123 to “proceed VOR, for radar to ILS RW 25R”.

Two minutes later at 12.02, the pilot of CAir035, an Airbus A340 departing from the airport, informs Departure Control (DEP) that he is climbing to FL90 and proceeding to LMN. DEP instructs him to continue towards LMN and report reaching.

CAir3365 is an Airbus A320 at FL90 on the same route as CAir035 but 10 miles ahead, also under control of DEP.

At 1205.00, Cair035 advises levelling at FL90 and request further climb. Unfortunately, the callsign is corrupt and DEP believes the message came from CAir 3365. He issues the instruction: “CAir 3365 climb report level FL200”.

DEP does not notice that the wrong aircraft has responded to the clearance.

A few seconds later, INI detects the conflict and instructs AirB123 to turn left heading 300. He advises AirB123 the he has “traffic 11 o’clock 5 miles same level, climbing”. He then instructs AirB 123 to “descend immediately to FL70”.

At 1205.50, DEP issues the instruction: “Cair035 maintain FL90, traffic crossing right to left, tern left heading 120”.

But Cair035 had already passed FL90. Five seconds later he reports “We have a TCAS TA. Traffic is in sight”.

DEP responds:”Cair035 descend immediately FL90, turn immediately left heading 090”.

At the same time, CAir035 receives a TCAS “climb” RA. He replies: ”Descending FL90, left 150 degrees, following TCAS”.

In fact the pilot continued to descend, contrary to his “climb” RA.

At 1206.30, AirB123 informs INI that he has the traffic in sight on his right hand side. The aircraft pass 1.5nm apart, both at FL90, descending.

Two aircraft with callsigns Cair035 and Cair3365 departed from the same airfield on similar initial tracks within a few minutes of each other. The potential for callsign confusion (same prefix, two digits in each suffix the same) was apparently not detected by the airline callsign deconfliction programme nor was it noticed by the controllers or the pilots of either aircraft.

The request from Cair035 for further climb was corrupt and the call sign was unclear. The DEP controller was expecting a climb request from Cair3365 and so assumed the call was from that aircraft and issued it with a clearance to climb to FL200 without first checking the call sign.

The pilots of Cair035 were expecting further climb clearance and accepted the clearance as being intended for them.

The DEP controller did not detect the error on readback. The fact that the pilot of Cair035 abbreviated his callsign at 1205.16 may have contributed to this error.

The pilot of Cair035 received a TCAS “climb” RA and reported to ATC that he was following it however he apparently continued to descend in accordance with ATC avoiding instructions.

LOSS OF SEPARATION – From several safety occurrences we recommend:

Дата добавления: 2014-11-29