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certified the B737-200s fit to continue flying, engineers say the planes are now expensive to operate.
Airzim grounded three of its Boeing 737 series last month after CAAZ indicated that the planes had passed their design service objective of 20 years and were increasingly becoming expensive to run.
Management at Airzim then requested Boeing to carry out an independent structural integrity inspection on the affected planes.
Although Boeing did not send its experts to Harare to carry out physical inspections on the aircraft, the manufacturer confirmed the planes were fit to fly.
Each of the three planes has an average 30 000 flight cycles and over 31 000-flight hours.
AIR ZIMBABWE
In a letter to Air Zimbabwe on Wednesday last week, Mr Andy Fixman – an official at Boeing’s commercial aviation services department – said the planes could still go up to 66 000 flight cy- cles.
On the Mandatory Modification and Inspection Programme, also known as service action requi-rements, Mr Fixman said: “Approximately 100 service bulletins are listed in Boeing document D6-38505, requiring modification or inspection.
“Many of these SBs (service bulletins) have a modification threshold of 75 000 flight cycles though some have earlier flight cycle thresholds – 20 years airplane age or a specific calendar threshold,” he said.
“Air Zimbabwe’s fleet is some of the later 737-200s manufactured, many of the SBs included in this document will not be effective on the ZMB (Air Zimbabwe) fleet.”
CAAZ had condemned Airzim’s 737 maintenance programme, saying it was not compliant with the minimum standards set by Boeing.
But in response, the Boeing representative said its implementation was “typically the first heavy check after 60 000-flight cycles.”
None of the grounded planes has reached such a flight cycle. They are fit to continue flying, argued Boeing.
On the supplemental structural inspection programme, Mr Fixman said: “The initial inspection threshold is 66 000 flight cycles and there is no requirement to perform inspections before that time . . . The threshold to begin these inspections is 66 000 flight cycles.”
When it directed the grounding of the three planes, CAAZ said the aircraft were susceptible to age-related defects, including components and other various systems.
“Of even greater concern are fatigue cracks that may develop. These weaknesses in the airframe structure, if left undetected and unrepaired, may lead to catastrophic failure of critical structural members and even disintegration of aircraft in flight,” reads a letter from CAAZ general manager Mr David Chawota to the Secretary for Transport, Communication and Infrastructure Development Mr Partson Mbiriri recen- tly.
But Boeing, allayed such fears with Mr Fixman saying: “The anticipated limit of validity for the Boeing 737-200 is well above the current hours and cycles on the ZMB fleet, so even after incorporating in 2013, there will be minimal impact on the ZMB fleet.”
Boeing said it had no recommendation to accomplish any actions earlier than the thresholds as mandated.
Section 5.0 of the letter from CAAZ refers to the recent 737-300 decompression event, along with the recently released inspections applicable to much later models and infers that these inspections should be carried out on the ZMB fleet.
Responding to this point, Mr Fixman said: “The recently released SB is only effective on the 737 line positions 2553 to 3132, which have a differently designed lap joint than that on the ZMB fleet manufactured at a different time.
“Inspections of lap joints in the location in question for the ZMB fleet . . . shall be performed prior to 45 000 flight cycles.”
In a letter to Mr Mbiriri dated March 25 this year, Mr Chawota raised a number of issues about the Boeing 737s.
He said: “The airline has failed to demonstrate that they have a current, updated pool of spare parts sufficient to support an evidently demanding aging fleet of airplanes such as the B737s.
“There is evidence of robbing spares from one B737 to another and mostly from the ground aircraft. This has, often times, resulted in a fleet wide cross contamination of defective systems and components. One defect would appear on all B737 over a period of time, one aircraft after another.”
He recommended the grounding of the planes arguing that Airzim had failed to maintain them according to the minimum design standards.
Efforts to get a comment from Mr Chawota yesterday were fruitless as his phone was not reachable.
The planes were subsequently grounded and a lease agreement with Zambezi Airlines was then signed to fill in the gap.
Zambezi Airlines pulled out of the agreement this week after Airzim reportedly failed to pay money owed to the airline amounting to US$460 000, resulting in Airzim cancelling all its regional routes yesterday.
There is only one major route left between Harare and London, in addition to its two domestic routes, acting chief executive Innocent Mavhunga said yesterday.
“Yes, there have been problems with Zambezi Airlines, but we are negotiating with our partners,” Mr Mavhunga told AFP.
“Only regional flights have been affected.”
The latest crisis to affect the national carrier comes days after it was suspended by International Air Transport Association (IATA) over a US$280 000 debt.
IATA spokesman Mr Chris Goater told AFP yesterday that Airzim would not be able to sell tickets through local or foreign travel agents until the debt was settled.
“We hope that it will clear its financial obligations to return to participation in IATA’s financial systems in short order,” he said.
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