Tailwind B734 at Lyon on Sep 7th 2010, descended below glide on LOC approach
Last Update: April 22, 2013 / 15:07:12 GMT/Zulu time
Incident Facts
Date of incident
Sep 7, 2010
Classification
Report
Airline
Tailwind Airlines
Flight number
TU-750
Departure
Tunis, Tunisia
Destination
Lyon, France
Aircraft Registration
TC-TLE
Aircraft Type
Boeing 737-400
ICAO Type Designator
B734
According to radar data the aircraft had descend to 250 feet AGL about 1.4nm before the runway threshold (editorial note: on a 3 degree glide required height would be 450 feet).
The BEA released their final report in French (English version released on Apr 22nd 2013) concluding the probable causes of the serious incident were:
- an incorrect identification of the final approach fix on the approach chart
- inadequate monitoring of the final approach vertical profile by the crew
Contributing factors were:
- the publishing of two final approach fixes as widespread on approach charts requiring to identify which one of the two to be used
- lack of information to the crew to identify the exact procedure to be used
The BEA complained, that following the minimum altitude alert issued at the control tower ATC prepared a safety report, which was handed to the BEA the following morning only, the crew did not notify the BEA at all. This prevented the BEA from downloading cockpit voice and flight data recorders.
In addition the BEA reported that according to documentation forwarded it was initially believed the supervising authority of the aircraft would be Tunisia, an according report was filed with Tunisia's CAA on Sep 8th, it turned out the Turkish CAA was responsible authority for the aircraft on Sep 9th and a report was filed with Turkey on Sep 9th, the NTSB representing the state of manufacture of the aircraft was notified as well.
The crew consisted of a captain (64, ATPL, 22,310 hours total, 16,100 hours on type) and a first officer (31, CPL, 1,150 hours total, 700 hours on type).
Approach control had initially cleared the aircraft to 4000 feet while on vectors for final approach, then cleared the crew to intercept the localizer at heading 320, the crew did not read back the heading. After the crew reported passing through the localizer, approach issued an updated vector of heading 020, cleared the aircraft to descend to 3000 feet and cleared the aircraft for the Localizer/DME approach to runway 36R, all instructions were read back correctly. The aircraft was subsequently handed off to tower.
The BEA annotated, that all aircraft were cleared to 3000 feet to begin their localizer approach during the period of time, the BEA processed the ATC tapes of that day. One of the most common approach charts depicted a localizer approach from 4000 feet showing an option for ATC clearance to 3000 feet and thus creating two final approach fixes.
The BEA reported that according to Boeing and operator flight crew operating manual the aircraft should be configured for landing before reaching the final approach fix (FAF), at crossing the FAF the MCP vertical speed should be adjusted to the previously computed rate of descent, the pilot monitoring then is responsible to monitor crossing points and intermediate altitudes. Upon reaching the minimum descent altitude (MDA) the pilot flying should call out whether the threshold of the runway is in sight permitting the approach to be continued below MDA or not requiring a go-around to be commenced.
The BEA analysed that the crew was never told the full title of the approach to be used, Localizer DME Y or Z approach to runway 36R with the Y/Z identification omitted, it was logical however that procedure Y would be used (intercept at 4000 feet). Due to lack of recordings available the BEA could not determine whether the crew had considered the possibility of procedure Z (intercept at 3000 feet) being used.
The aircraft was level at 3000 feet about 2:20 minutes prior to starting the final approach, the crew did not perceive the FAF at 10 DME (as provided for an intercept at 4000 feet) unusual. The aircraft thus began the descent at that FAF.
Multiple segments indicating minimum altitudes at fixed DME distances were provided on the vertical profile, the aircraft had to remain above such minimum safe altitudes for each of the segments at all times. Besides the use of EGPWS this was the crew's only safe guard against terrain obstacles. The BEA analysed, that this monitoring of segments, crossing points and intermediate altitudes has clearly not been applied.
The BEA further analysed that it appeared the crew did not understand why they had been instructed to go around and stated that the instruction to go-around did not match standard phraseology.
4 safety recommendations were released as result of the investigation, amongst them to discontinue the publication of two FAFs on the same approach chart and require controllers to fully identify the procedure to be used.
Incident Facts
Date of incident
Sep 7, 2010
Classification
Report
Airline
Tailwind Airlines
Flight number
TU-750
Departure
Tunis, Tunisia
Destination
Lyon, France
Aircraft Registration
TC-TLE
Aircraft Type
Boeing 737-400
ICAO Type Designator
B734
This article is published under license from Avherald.com. © of text by Avherald.com.
Article source
You can read 2 more free articles without a subscription.
Subscribe now and continue reading without any limits!
Read unlimited articles and receive our daily update briefing. Gain better insights into what is happening in commercial aviation safety.
Send tip
Support AeroInside by sending a small tip amount.
Related articles
Tailwind B734 near Bucharest on Sep 8th 2023, suspected fuel leak
A Tailwind Airlines Boeing 737-400, registration TC-TLE performing flight TI-797 from Antalya (Turkey) to Prague (Czech Republic) with 112 people on…
Tailwind B734 at Liege on Jul 31st 2015, dropped flap seal plate on approach
A Tailwind Boeing 737-400, registration TC-TLE performing flight TI-477 from Bodrum (Turkey) to Liege (Belgium), completed what appeared to be an…
Tailwind B734 at Antalya on Aug 15th 2022, engine problem
A Tailwind Boeing 737-400, registration TC-TLC performing flight TI-291 from Antalya (Turkey) to Zurich (Switzerland), was climbing through FL190 out…
Tailwind B734 near Sofia on Mar 11th 2018, "we have lost the cabin"
A Tailwind Airlines Boeing 737-400 on behalf of Corendon Air, registration TC-TLC performing flight XC-1845 from Antalya (Turkey) to Zurich…
Tailwind B738 at Friedrichshafen on Oct 8th 2016, flaps problem
A Tailwind Boeing 737-800, registration TC-TLH performing flight TI-9227 from Antalya (Turkey) to Friedrichshafen (Germany) with 183 people on board,…
Newest articles
American B773 near Buenos Aires on Oct 31st 2024, unusual noise from cargo hold
An American Airlines Boeing 777-300, registration N717AN performing flight AA-954 from Buenos Aires Ezeiza,BA (Argentina) to New York JFK,NY (USA),…
Piedmont E145 at Philadelphia on Oct 31st 2024, engine shut down in flight
A Piedmont Embraer ERJ-145 on behalf of American Airlines, registration N650AE performing flight AA-5928 from Philadelphia,PA to Cincinnati,KY (USA)…
Subscribe today
Are you researching aviation incidents? Get access to AeroInside Insights, unlimited read access and receive the daily newsletter.
Pick your plan and subscribePartner
A new way to document and demonstrate airworthiness compliance and aircraft value. Find out more.
ELITE Simulation Solutions is a leading global provider of Flight Simulation Training Devices, IFR training software as well as flight controls and related services. Find out more.
Your regulation partner, specialists in aviation safety and compliance; providing training, auditing, and consultancy services. Find out more.
AeroInside Blog
Popular aircraft
Airbus A320Boeing 737-800
Boeing 737-800 MAX
Popular airlines
American AirlinesUnited
Delta
Air Canada
Lufthansa
British Airways