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ASN Wikibase Occurrence # 193313
Last updated: 22 April 2019
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Date:30-JUN-2015
Time:12:26 UTC
Type:Silhouette image of generic E170 model; specific model in this crash may look slightly different
Embraer ERJ-170STD (ERJ-170-100)
Owner/operator:LOT - Polish Airlines
Registration: SP-LDK
C/n / msn: 17000074
Fatalities:Fatalities: 0 / Occupants:
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:Sofia FIR -   Bulgaria
Phase: En route
Nature:International Scheduled Passenger
Departure airport:Warszawa-Frédéric Chopin Airport (WAW/EPWA)
Destination airport:Istanbul-Atatürk International Airport (IST/LTBA)
Investigating agency: AAIU Bulgaria
Narrative:
LOT flight LO7293, an Embraer ERJ-170, was involved in a serious airprox incident over Bulgaria with a Dassault Falcon 900 (VP-CGD), operating a flight from Stuttgart, Germany to Muscat, Oman.
LO7293 was flying in Romanian airspace when the transponder failed. It switched to STANDBY mode, as a result of which the TCAS mode TA/RA switched to OTHER mode. The secondary radar target then showed as a '-'.
It continued into Bulgarian airspace, the Sofia FIR Varna East Upper airspace. The Romanian controller instructed the flight crew to contact the controller of the Varna West sector.
meanwhile the Varna East controller was coordinating with an approaching Falcon 900, flight WGT62N, that there was unknown traffic at an unknown altitude on a course that would cross their path. The crew of flight WGT62N reported that the traffic was in sight. The crew kept the aircraft in sight until it had crossed. The horizontal distance between WGT62N and LO7293 was 0,9 nm (1670 m), at the same FL370.
One minute later the transponder of LO7293 began transmitting again. It had been inoperative for 30 minutes.

Main cause:
- Unintentional interruption of the Air Traffic Service in regard to LOT7293 on the side of ACC Bucharest after changing of the aircraft transponder mode of operation to STANDBY, particularly in Bucharest Control BANAP sector, during the its flight in Bucharest FIR and later on in Sofia FIR.

Accompanying causes:
- Not implemented procedures by the flight crew of Embraer 170, registration marks SPLDK, after the momentary failure of the transponder system.
- Not provided information in timely manner on the location, direction of flight and height of the unidentified aircraft by ACC Bucharest to ACC Sofia, previously received from NATO07.
- Not implemented procedures by ACC Bucharest from the LETTER OF AGREEMENT between BULATSA SOFIA ACC and ROMATSA BUCUREŞTI ACC/CONSTANŢA APP:
- E.1 Transfer of Control
- E.2 Transfer of Communications;
- F.2.5 Transfer of Aircraft Identification.

Sources:

https://www.mtitc.government.bg/sites/default/files/uploads/zveno/final_report-lot7293-wgt62n_eng.pdf

Safety recommendations:

Safety recommendation BG.SIA-2015/03/01 issued 19 December 2016 by AAIU Bulgaria to ROMATSA
Safety recommendation BG.SIA-2015/03/02 issued 19 December 2016 by AAIU Bulgaria to ROMATSA
Safety recommendation BG.SIA-2015/03/03 issued 19 December 2016 by AAIU Bulgaria to ROMATSA
Safety recommendation BG.SIA-2015/03/04 issued 19 December 2016 by AAIU Bulgaria to ROMATSA
Safety recommendation BG.SIA-2015/03/05 issued 19 December 2016 by AAIU Bulgaria to ROMATSA
Safety recommendation BG.SIA-2015/03/06 issued 19 December 2016 by AAIU Bulgaria to LOT
Safety recommendation BG.SIA-2015/03/07 issued 19 December 2016 by AAIU Bulgaria to EASA; ICAO
Safety recommendation BG.SIA-2015/03/08 issued 19 December 2016 by AAIU Bulgaria to BULATSA and ROMATSA
Safety recommendation BG.SIA-2015/03/09 issued 19 December 2016 by AAIU Bulgaria to BULATSA

Accident investigation:
cover
  
Investigating agency: AAIU Bulgaria
Status: Investigation completed
Duration:
Download report: Final report


Images:

Photo of SP-LDK courtesy AirHistory.net


Berlin - Tegel (EDDT / TXL)
13 September 2012; (c) Alastair T. Gardiner

Revision history:

Date/timeContributorUpdates
05-Feb-2017 19:30 harro Added
05-Feb-2017 20:25 harro Updated [Time, Narrative]
05-Feb-2017 20:26 harro Updated [Source]

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