Graham Warwick/WASHINGTONDC
BOMBARDIER EXPECTED most of the 38 Canadair Regional Jets (CRJs) found to have fuselage-bulkhead cracks to be back in operation by 5 July. Repair of the final eight aircraft is awaiting the availability of hangar space.
The repair takes three days and involves attaching a sheet-metal patch to the cracked pressure-bulkhead, which is located forward of the wing where it passes through the fuselage and which is reached via an access panel in the wing-fuselage fairing. Bombardier despatched repair teams in late June and is picking up the C$6,000 ($4,330) per aircraft cost.
Cracking was discovered after operator Skywest reported difficulty maintaining full cabin pressurisation on a flight on 19 June. Inspection of the aircraft revealed a 350mm crack in the bulkhead at the forward end of the fuselage wing-box cut-out. The fatigue crack is caused by a higher than predicted stress concentration in a corner of a cutout in the bulkhead.
About 9,000h had been accumulated on the aircraft when the crack was discovered. An airworthiness directive was issued requiring visual inspections within 10h and every 100h thereafter. All 166 CRJs in service were inspected and 38 aircraft with six operators were found to have similar cracks. Seven of Skywest's ten CRJs had cracks.
Source: Flight International
