Braathens Regional RJ1H at Gothenburg on Nov 7th 2016, vibrations at high speed

Last Update: December 7, 2017 / 15:52:41 GMT/Zulu time

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Photo of Braathens Reginal Airlines SE-DSV, AVRO RJ-100 Avroliner — Braathens Reginal Airlines SE-DSV, AVRO RJ-100 Avroliner (Photo credit: OsdPhoto.com / Flickr / License: CC by)

Incident Facts

Date of incident
Nov 7, 2016

Classification
Incident

Airline
Braathens Reginal Airlines

Flight number
TF-1

Departure
Gothenburg, Sweden

Destination
Stockholm Bromma, Sweden

Aircraft Registration
SE-DSV

Aircraft Type
AVRO RJ-100 Avroliner

ICAO Type Designator
RJ1H

Airport
Gothenburg-Landvetter Airport, Gothenburg

Airport ICAO Code
ESGG

A Braathens Regional Avro RJ-100, registration SE-DSV performing flight TF-1 from Gothenburg to Stockholm Bromma (Sweden) with 50 passengers and 5 crew, departed Gothenburg's runway 03 and was accelerating and retracting the flaps when the crew observed unusual vibrations, declared emergency, slowed the aircraft down causing the vibrations to cease and returned to Gothenburg for a safe landing on runway 21 about 7 minutes after departure.

The occurrence aircraft remained on the ground in Gothenburg for about 15 hours, then positioned to Stockholm Arlanda (Sweden) as flight TF-9803, but has not yet returned to service 18 hours after the occurrence.

On Dec 7th 2017 Sweden's Haverikommission (SHK) released their final report in Swedish concluding the probable cause of the incident was:

The incident was partly caused by the lack of sufficiently detailed procedures to perform a complete check for ice accretion, the existing procedures were not fully applied and partly because the operator had not adequately assessed and verified the working methods by sub contractors.

A contributing factor was that in the de-icing agency there was not sufficient support for working staff to deal with the real time demands and to ensure that de-icing is being carried out properly despite actual or perceived lack of time.

The SHK reported the aircraft had been parked outdoors for about 40 hours prior to departure for the occurrence flight, during that time there had been heavy precipitation with snow and winds. Prior to departure a one time inspection was scheduled carried out by a subcontractor to determine accretion of snow and ice.

After departure and retracting the flaps, when the crew attempted to accelerate the aircraft beyond 195 KIAS, vibrations occurred. The captain took control of the aircraft, disengaged the autopilot and slowed the aircraft. The crew subsequently decided to return to Gothenburg and declared emergency. When the speed increased again, the vibrations returned, the crew again slowed the aircraft until the vibrations ceased. The aircraft returned to Gothenburg for a safe landing. After landing extensive ice accretion was discovered on several control surfaces of the airframe.

The investigation determined that the aircraft is particular sensitive to mass balance in the aircraft control systems. Even very thin layers of ice are sufficient to unbalance the rudder control system. In this case the layers of ice were extensive. The investigation thus analysed that the vibrations were the result of inbalance caused by those layers of ice.

It is obvious that prior to departure the personnel tasked to inspect the aircraft for ice accretion did not detect all ice accretions and thus de-icing was not done on those surfaces.

The investigation further analysed that the operator's procedures were not detailed enough to perform an inspection catching all possible layers of ice, in addition the procedures already laid out by the operator were not fully followed.

Metars:
ESGG 070650Z 03013KT 9999 FEW016 M05/M07 Q1012 R03/19//95
ESGG 070620Z 03014KT 9999 FEW017 M05/M07 Q1012 R03/19//95
ESGG 070550Z 03015KT CAVOK M04/M07 Q1011 R03/290195
ESGG 070520Z 03013KT CAVOK M04/M07 Q1011 R03/290195
ESGG 070450Z 03012KT CAVOK M05/M07 Q1011 R03/290195
ESGG 070420Z 03012KT CAVOK M05/M07 Q1011 R03/290195
ESGG 070350Z 03012KT CAVOK M05/M07 Q1011 R03/290195
ESGG 070320Z 03011KT CAVOK M05/M07 Q1011 R03/290195