Enter B734 near Girona on Sep 28th 2016, near collision with light aircraft due to lightning

Last Update: November 7, 2017 / 19:18:33 GMT/Zulu time

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Photo of Enter Air SP-ENA, Boeing 737-400 — Enter Air SP-ENA, Boeing 737-400 (Photo credit: eisenbahner / Flickr / License: CC by)

Incident Facts

Date of incident
Sep 28, 2016

Classification
Incident

Cause
Near collision

Airline
Enter Air

Flight number
E4-1237

Departure
Warsaw, Poland

Destination
Girona, Spain

Aircraft Registration
SP-ENA

Aircraft Type
Boeing 737-400

ICAO Type Designator
B734

An Enter Air Boeing 737-400, registration SP-ENA performing flight E4-1237 from Warsaw (Poland) to Girona,SP (Spain) with 6 crew, was on approach to Girona in contact with Barcelona,SP (Spain) Approach and was cleared for the approach to Girona's runway 02 when the crew received a TCAS resolution advisory at about waypoint TISGO and complied with the resolution advisory. The aircraft continued the approach for a safe landing on Girona's runway 02.

Spain's CIAIAC reported a Cessna 172 operated for a flight school was being vectored for the approach to runway 02 at the same time, the separation between the aircraft reduced to 100 feet vertical and 0.5nm horizontal. At the time of the occurrence the BEGUES radar system was out of service due to a lightning strike and the communication beween Girona Tower and Barcelona Approach was lost due to an electrical problem. Both aircraft landed safely on Girona's runway 02. The CIAIAC rated the occurrence a serious incident and opened an investigation.

On Oct 20th 2017 (and overlooked by the AVH until Nov 7th 2017 due to only the Cessna being mentioned in the list of reports) Spain's CIAIAC released their final report concluding the probable causes of the serious incident were:

The main cause of the incident was the loss of situation awareness of the controllers in sectors D1E and TGR after the sectors were opened. Aircraft EC-JOB, which was inbound from the Calella VOR and should have been under the control of sector TGR, was cleared by sector D1E to complete its approach to runway 02 at the Girona Airport. After this, sector TGR instructed aircraft SP-ENA to also approach inbound from OKETA, which caused a loss of separation between the two aircraft in the vicinity of the intermediate approach fix TISGO.

The following factors contributed to the incident:

- Sectors were opened at a time when there was a high workload for the controllers in sector T1E.

- There were several aircraft doing aerial work, and when the TMA configuration change occurred, these aircraft conflicted with operations at LEBL, which forced the controllers in sector D1E to focus their attention on managing these aircraft, a task that was not properly coordinated with the newly-opened sector TGR.

- The temporary outage of the air navigation data network, which caused the radar display for traffic below 3200 ft to be lost, along with the updated flight plans and communications between LEGE and the Barcelona ACC, requiring the use of telephone communications. All of this contributed to having the sector TGR controllers focus their attention on determining the position of aircraft EC-GGF, inbound to LEGE. This, combined with the loss of coordination with sector D1E, made them become unaware of other traffic affecting them.

The CIAIAC analysed the loss of separation:

On 28 September 2016, a Boeing 737-400 aircraft, registration SP-ENA and callsign ENT1237, was flying from the Warsaw-Chopin Airport to the Girona Airport. At the same time, a Cessna 172, registration EC-JOB and callsign ECJOB, was flying from the Sabadell Airport to the Girona Airport.

The first aircraft was following standard terminal arrival route BGR1L, while the second was on route SLL1K. Both aircraft were in radio contact with the sector T1W controller in the Barcelona ACC.

Based on the information provided, at 08:44 the REDAN network went offline, which resulted in the loss of communications between Girona TWR and the Barcelona ACC. The SACTA system was also lost, along with the information from the Girona radar, meaning that traffic below 3200 ft was not displayed on the radar screen.

At 08:50, the configuration of the TMA was changed for weather reasons. As a result, to avoid overloading the sector T1E ATCOs, sectors TGR and D1E were opened at the TMA, with the ATCOs for sector T1 being placed in charge of D1E and two new ATCOs going on duty to handle sector TGR. In this configuration, both SP-ENA and EC-JOB should have been under the control of sector TGR. At 08:59:23, the executive controller in sector D1E cleared aircraft EC-JOB to make the approach to runway 02 at the Girona Airport without informing sector TGR.

Under these conditions, it is sector TGR that handles approaches to runway 02 at Girona. When this sector was opened, its controllers were not informed about the aircraft flying from Sabadell to Girona (ECGGF, ECJOB and ECGIJ), and thus they were initially unaware of said traffic. Although the Girona tower controller checked with sector TGR about flight ECJOB at 08:55:42, he did not receive a reply since the ATCO at said sector was unaware of the existence of ECJOB. This traffic was visible on the display, but the sector’s ATCO was focused on finding out the position of ECGGF, which had been transferred to the Girona TWR at 08:50:45 by sector T1E and was completing its approach without being visible on the radar due to the loss of the network. The last radar blip for this traffic had been at 08:54:37, when it descended below 3200 ft.

Following this, at 09:00, the TGR sector ATCO, not knowing that aircraft EC-JOB had been cleared to make its approach by sector D1E, also instructed aircraft SP-ENA to complete the approach from point OKETA to runway 02 at Girona. Both aircraft converged near point TISGO, resulting in a loss of separation and the TCAS advisory being issued at approximately 09:05. The minimum distance recorded was 0.4 NM and 200 ft. Weather conditions allowed the crews of both aircraft to remain in visual contact at all times. The crew of aircraft EC-JOB decided to turn left to separate from SPENA, while the latter continued its approach without disengaging the autopilot, eventually landing on runway 02.

Thus, a series of factors occurred simultaneously (change in TMA configuration, opening of sectors, loss of the REDAN network and use of infrequent routes) that contributed to the lack of proper coordination between the ATCOs in sectors D1E and TGR, who practically simultaneously cleared the two aircraft to make the approach to runway 02 at the Girona Airport.