Blue B734 at Cluj on Jan 7th 2016, runway excursion on landing

Last Update: December 21, 2016 / 16:51:33 GMT/Zulu time

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Incident Facts

Date of incident
Jan 7, 2016

Classification
Incident

Cause
Runway excursion

Airline
Blue Air

Flight number
0B-9301

Departure
Bucharest Otopeni, Romania

Destination
Cluj, Romania

Aircraft Registration
YR-BAS

Aircraft Type
Boeing 737-400

ICAO Type Designator
B734

Airport
Cluj-Napoca International Airport, Cluj-Napoca

Airport ICAO Code
LRCL

A Blue Air Boeing 737-400, registration YR-BAS performing flight 0B-9301 from Bucharest Otopeni to Cluj (Romania) with 110 passengers and 6 crew, landed on Cluj's runway 25 at 08:02L (06:02Z) but overran the end of the paved surface of the runway by about 20 meters (65 feet) before coming to a stop. No injuries occurred, the aircraft sustained no damage. The passengers disembarked normally via mobile stairs and were bussed to the terminal.

The airline reported the aircraft landed in difficult weather conditions with snow as well as snow deposits on the runway. According to the weather and runway data provided by tower the conditions, including braking action, were within acceptable limits however.

Cluj Airport reported the runway was wet in snowy conditions, the braking action was reported medium.

Cluj features a runway 07/25 of 2040 meters/6700 feet length.

On Dec 20th 2016 Romania's CIAS released their final report in Romanian concluding the probable causes of the serious incident were:

The cause of the serious incident was an extended flare/float, that resulted in touch down 2300 feet/700 meters past the runway threshold.

Contributing factors were:

- winds from 100 degrees magnetic at 5-10 knots
- landing speed was 140 KIAS, 11 knots faster than computed according to AOM (129 KIAS)
- the flare was initiated at 45 feet AGL rather than 25 feet AGL as recommended by Boeing
- the runway was covered with wet snow up to 1cm, which covered 51-100% of the runway surface
- insufficient visual cues
- inconsistent brakes pressure on brake pedal operation

The CIAS reported the crew was advised of 3mm of snow on the runway surface, braking action was reported medium (measurement before had resulted in brake coefficients consistent with good to medium, it was estimated due to the ongoing snow fall the braking action would be medium at the time of landing). The aircraft was configured for flaps at 40 degrees, gear down, autobrakes position 3 and spoilers armed. The crew acquired visual contact with the runway descending through 800 feet AGL, the captain (32, ATPL, 3,856 hours on type), pilot flying, initiated the flare at 45 feet AGL which caused a prolonged float. The aircraft touched down about 2300 feet past the runway threshold, the captain deployed thrust reversers, automatic brakes engaged. In the last part of the roll out the captain operated the brakes pedals disconnecting the autobrakes, however, was not able to slow the aircraft in time to avoid an overrun. The aircraft veered to the right, passed the runway end at about 10 knots over ground and stopped in the vicinity of the end turned to the right.

The CIAS analysed that the landing distance required with maximum autobrakes would have required 1668 meters, with maximum manual braking 1650 meters, with autobrakes position 3 1769 meters, all computations assuming braking action medium. Landing distance available was 2040 meters. Due to the touchdown 700 meters past the runway threshold the remaining landing distance available was no longer sufficient to safely stop the aircraft on the runway. The investigation computed that the aircraft would have safely stopped on the runway, had it touched down 401 meters past the runway threshold at the latest.

The CIAS did not find any flaw in the operation of ATC.

The CIAS also did not find any flaw in th snow removal procedures by the aerodrome. A degradation of braking action between vehicles leaving the runway and the time the aircraft would land was taken into account. The runway had been cleared with focus on the center part of the runway, at the edges the snow may have been up to one inch high.

The CIAS analysed that the aerodrome operator was under the impression the aircraft had declared emergency advising they had just 5 minutes flying time left and thus rushed the runway clearing, starting from the touch down zone down towards the runway end (rather than the opposite way round that would be normal). This contributed to the touch down zone being exposed to snow fall for a longer than normal time.

The CIAS analysed that the achieved deceleration was close to the target for autobrakes 3 when the aircraft slowed through 80 knots. Subsequently a maximum left brakes input was provided which disconnected the autobrakes, brakes pressure was subsequently released and deceleration became about half of target. Subsequent brakes inputs oscillated, the brakes pressure rose and decreased accordingly as did the deceleration. When the aircraft slowed through 32 knots, deceleration substantially decreased however, most likely as result of contamination of the runway.

All components of the braking system worked normally.

Metars:
LRCL 070800Z 00000KT 0600 R25/0650N -SN FG BKN002 OVC015 01/01 Q0995 R07/590393
LRCL 070730Z 23002KT 0600 R25/0650N SN FG SCT002 OVC003 00/00 Q0995 R07/590393
LRCL 070700Z 11002KT 0700 R25/0900U SN FG BKN003 OVC005 00/00 Q0995 R07/590393
LRCL 070630Z 08005KT 0700 R25/0900U SN FG SCT003 OVC008 00/00 Q0995 R07/590393
LRCL 070600Z 09003KT 1000 R25/0900V1400D SN BR SCT009 OVC010 00/00 Q0995 R07/590393
LRCL 070530Z 10002KT 1200 R25/1400D SN BR SCT013 OVC016 00/M00 Q0995 R07/690294
LRCL 070500Z 08004KT 1500 SN BR FEW020 OVC028 M00/M00 Q0994 R07/690294
LRCL 070430Z 08001KT 2500 -SN BR FEW022 OVC030 M00/M00 Q0994 R07/690294
LRCL 070400Z VRB01KT 3000 -FZRASN BR SCT021 OVC030 M00/M00 Q0994 R07/690294
LRCL 070330Z 00000KT 3000 -SN BR FEW026 OVC046 M01/M01 Q0994 R07/29//95
LRCL 070300Z 25003KT 3000 -FZRA BR OVC052 M01/M01 Q0995 R07/29//95