Case Studies

Rosebank Acknowledges the support of the System Program Offices, Defence Material Organization, Defence Scientific and Technology Organization, and associated programs.

Engineering Reliability Improvements – A Case Study

F-111 Horizontal Tail Servo Actuator

Rosebank was chosen by the RAAF to establish an innovative solution to a demanding flight critical system on the F-111. The Horizontal Tail Servo Actuator (HTSA) had a history of galling and oscillation. The Mean Time Between Failure (MTBF) established, saw the U.S experience of approx. 250 hrs reduced to an average MTBF of 40 to 50 hours. This produced significant RAAF logistics cost burdens and the potential to see Aircraft on Ground (AOG) occurring on a regular basis.

Rosebank instigated a innovative approach to the problem by looking at the dynamics of the component and system interaction and providing a new basis of developing a marriage of intellectual property algorithms that would predict the optimal amount of material to be removed together with purpose built facilities and innovative machining techniques that would reduce logistics and cost of asset through life to a mere fraction of the past costs.

This has seen to April 2007:

  • 159 valves now overhauled and recovered
  • 90 achieved full overhaul life of 1,025 hrs operational life!
  • 26 were removed for USAF standard modification action
  • 49 have accrued in excess of 500 hrs operational life
  • 10 removals due to valve failure (seal failure) after 500 hours.
  • Remainder are in service or service stock
  • Average recovery cost approx one tenth of new replacement price and TAT approx a third

Sea King Helicopter Pump Housing-A Case Study

The Navy Aviation Systems Program Office (NASPO) was experiencing continual problems with the Sea King Helicopter Pump Housing due to poor material selection in the initial design and development phase. This lead to problems in age deterioration, overheating during operation and poor reliability.

The replacement TAT and regularity of R&O of the Sea King Helicopter Hydraulic Pump Housing were resulting in long lead times and higher costs to NASPO. Rosebank was approached to undertake re-engineering to overcome existing limitations and provide a local supply for the Sea King Helicopter Hydraulic Pump Housing. Rosebank conducted research and engineering analysis including alternate material selection, enhanced processing, assembly and test, qualification and acceptance methods.

Consequently, Rosebank carried out new validation programs to support the newly engineered Pump Housing which was subsequently entered into Navy service. The new design resulted in increased reliability and elimination of overheating.

In country engineering of the new design decreased lead times and a saving of US$3.4k per housing for the Navy.

Reliability Improvements- P3 Boost Control Valve - A Case Study

Australia ’s fleet of P3 Orion Boost Control Valves was originally sent overseas for repair and overhaul due to a gap in country deeper maintenance capability. . As a result of this, the P3 experienced high rates of unrecoverable unserviceable stock, extended lead times, and extreme high costs associated with service, which, if recovery was available, in excess of US$50k.

Rosebank conducted research and engineering analysis into the development of in country repair and overhaul capabilities for P3 Boost Control Valves.

Rosebank conducted R&D in the areas of alternate material, enhanced processing, assembly and test redefinition and GSE manufacture. Component specific Validation and Certification programs were also developed to support the implementation of the overhaul research. Consequently, Rosebank developed a reliable in country support for this component which reduced units costs down to US$3.4K -$5.4K and a vastly improved recovery time.

Reliability Improvements Asset Retention

F/A – 18 Hydraulic Reservoir

The F/A – 18 Hydraulic Reservoir was suffering damage outside published limits stated by the OEM (Parker Aerospace).

The repair scheme developed by Parker had so fine a repair limit, that it meant that Rosebank couldn’t undertake repairs because of the stated limitations of the current repair scheme.

Rosebank developed a model to test the stresses experienced by the reservoir. Stresses were applied to the model and the load monitored which validated the stress areas. In turn, Rosebank developed computational analysis which formed the basis for an improved repair plan on the reservoir. These tests proved that increased damage could be removed, and consequently via a series of hydraulic and cyclic testing, was able to validate and certify the repair. It has since been adopted on all F/A-18 aircraft.

Reliability Improvements Asset Retention

P-3 Nose Wheel Steering Valve Body – A Case Study

There was no repair scheme provided for the P-3 Nose Wheel Steering Valve Body, therefore the cost of replacement was in excess of US$25k plus a minimum 65 week lead time based on a minimum order. The RAAF were dissatisfied and concerned with the increasing logistics burden affecting the component.

Rosebank conducted initial research on the component including FEA research and enhanced plating recovery to find they could repair and overhaul, at a much lower cost than replacement value.

Rosebank conducted the engineering analysis and subsequent validation programs.

The mature cost of the repair of P3 NWS valve body is US$3.9k

Seahawk Rast Fitting – A Case Study

Rosebank received a request from the Navy Aviation Systems Program Office (NASPO) to establish a local supply of RAST spares as they were finding it difficult to obtain timely spares. The Original Equipment Manufacturer (OEM) drawings were provided by NASPO. It was found that there were some anomalies in the drawing and Rosebank subsequently conducted an engineering program to overcome these deficiencies. Rosebank therefore had to interpret the errors in the drawings and correct them in order to manufacture serviceable components.

Rosebank has the proven capability to carefully interpret drawings and pin point errors that would otherwise render inoperative the manufactured part, which could result in unnecessary time, higher logistical expenditure and Aircraft on Ground (AOG). Rosebank is now the local supplier of Seahawk Rast fittings for a considerably smaller economic costs and a much faster turn-around-time for the operators. Operators have also remarked how much easier the Rast fitting are to install.