West Atlantic AT72 at Guernsey and Jersey on Apr 16th 2021, cargo shift in flight

Last Update: February 10, 2022 / 18:46:39 GMT/Zulu time

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Photo of West Atlantic G-CLNK, ATR ATR-72-200 — West Atlantic G-CLNK, ATR ATR-72-200 (Photo credit: Alec BHX/KKC / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Apr 16, 2021

Classification
Report

Airline
West Atlantic

Flight number
NPT-904

Departure
Guernsey, United Kingdom

Destination
Jersey, United Kingdom

Aircraft Registration
G-CLNK

Aircraft Type
ATR ATR-72-200

ICAO Type Designator
AT72

A West Atlantic Avions de Transport Regional ATR-72-200 freighter, registration G-CLNK performing flight NPT-904 from Guernsey,CI to Jersey,CI (UK) with 2 crew, was taking off from Guernsey when the crew heard a thud sound which they attributed to water bottles moving in the cabin. Without feeling an anomaly in the flight controls the aircraft continued to Jersey for a safe landing about 15 minutes after departure. During the landing roll they heard a sliding sound closely followed by another loud thud. The aircraft vacated the runway and taxied to the stand.

The AAIB released their bulletin reporting a Unit Load Device (ULD) which had been loaded on pallet position C3 (middle) had moved rearwards into position C4 and was stopped by the ULD in C5 during takeoff, then as soon as the brakes were applied for slowing the aircraft during landing the ULD moved forward, broke through the forward locks and was stopped by the ULD in position C1. The AAIB reported the ground handling organisation performed an investigation and reported:

The investigation by the ground handling organisation found that the loader may have been distracted during the loading; moreover, there was no requirement for an independent check of the locks to be carried out as the ULD were loaded.

The organisation introduced safety actions revising their loading procedure to provide for an indepdent verification that all locks are in the correct position when the aircraft is loaded.

The AAIB reported:

During the morning the aircraft had flown from East Midlands Airport to Guernsey with a full load of five freight containers (ULDs). The ground handling team met the aircraft and two ULDs were unloaded. The remaining three ULDs were re-positioned within the aircraft in positions C1, C3 and C5.

The pilots checked that the load tallied with the loading information report and closed the doors at 0610 hrs. As the aircraft accelerated during the takeoff for a flight to Jersey, the crew heard a ‘slight thud’, which they attributed to the movement of some water bottles in the cabin. During the 15-minute flight the pilots did not notice any change to the feel or control of the aircraft. The aircraft touched down normally and when the brakes were applied the pilots heard a sliding noise closely followed by a ’loud thud’ which was felt through the airframe.

The aircraft cleared the runway and the co-pilot moved to the cabin to assess the load but could only see the ULD in C1 which was correctly positioned. Once on stand, the ground handlers inspected the load and discovered that the ULD initially loaded in bay C3 had moved to C2.

ULDs are filled, weighed and their position in the aircraft determined by the loading planners prior to being delivered to the aircraft. They are then individually loaded onto the aircraft at the forward cargo door and pushed into position by hand. The ULD slide along rails that are attached to the cargo bay floor.

Locks that secure the ULDs in position are located between the bays and like the rails are attached to the fittings on the floor. The position of each bay is indicated by green markers on the cargo bay walls. The locks can be positioned down to allow ULDs to slide over them and up to lock ULDs in position.

The locks can be used as a rear restraint, a forward restraint or when positioned between two ULDs as both a forward and rear restraint. When loading the aircraft, the locks at the rear of the bay in which the ULD is to be positioned should be in the up position and the ULD is moved rearwards until it engages with these locks. Once in position, the forward locks are raised and engage with the front of the ULD preventing it from moving forward.

Examination of the aircraft Examination of the aircraft by the operator found that the locks and rails between bays C2 and C3 were damaged and dislodged (Figure 4), and the locks to the rear of bay C3 were down. The locks between bays C2 and C3 had been pulled out of the tracks in the cargo bay floor within which they were attached.

The ULD that moved in flight was found to be undamaged and there was no other damage to the aircraft.

Investigation by ground handling organisation

An investigation by the ground handling organisation identified that when the ULD in bay C3 was moved into location, the locks between bays C3 and C4 were not raised and remained in the down position; however, the forward locks were raised. During the takeoff roll the slight thud heard by the crew was probably the ULD in bay C3 sliding rearwards to bay C4 and stopping against the forward locks which restrained the ULD in C5. During the landing the ULD would have slid forward as the aircraft decelerated, breaking the locks between bays C2 and C3 which were in the up position. Its movement would then have been arrested when it hit the raised locks to the rear of the ULD in C1.

The AAIB further stated:

An assessment of the weight and balance of the aircraft, following the forward and rearward movement of the ULD loaded in bay C3, established that the aircraft remained within the forward and aft limits throughout the flight.