In September 2010, a Republic of Singapore Air Force (RSAF) Boeing AH-64D Apache suffered a dual-engine failure while conducting a test flight, resulting in a hard landing on an open field. No one was hurt in that incident, but the tail boom broke off on impact. Investigations revealed that the engine’s anti-ice start bleed valve had corroded over time, and with no official procedures to check the internal component during maintenance, the whole episode made everyone, including the manufacturers, realize that a different sustainment approach is needed for the harsh conditions in Southeast Asia.
As more states begin to look at Boeing products such as the Apache attack helicopter, Boeing (Chalets S23, U09, U23) is looking to tailor its various logistics and sustainment solutions to potential and current customers.
“For tropical environments, corrosion is a significant issue and specific corrosion prevention procedures and practices are required. During production or deep maintenance, anti-corrosion paints or compounds are applied to the airframe and components, enhanced aircraft cleaning procedures with increased frequency are employed, and timelines to react to any indication of corrosion are greatly increased,” said Mark Ballew, Boeing director of global sales and marketing for international government services. “Corrosion is going to happen in tropical environments, and proactive corrosion prevention must be employed to ensure the long-term reliability of the aircraft.”
Corrosion prevention and repair is a major concern in a tropical environment, and he noted that the level of additional maintenance will depend on the duration of operations over saltwater, proximity to saltwater, exposure to outside environments, and proximity to volcanic activity or to an area with high concentrations of chlorine.
Although application of anti-corrosive paints or solvents will be completed during production and heavy maintenance, the frequency of component inspection and aircraft cleaning will increase with exposure to corrosive environments.
“It’s difficult to quantify the extra maintenance required, but as an example, aircraft washing alone should be happening six times more frequently monthly compared to aircraft stationed in an arid climate. In some instances, a daily wash after flight is required, or if the aircraft are stored outside critical components are required to be washed and wiped with fresh water daily,” Bellew added.
The AH-64E Guardian, currently used by the Indonesian Army, has extra coatings on the fuselage and components to help prevent corrosion, and Boeing has developed a focused sustained preventive maintenance program to forecast and predict parts and components repairs to improve maintenance efficiency and aircraft readiness.
Boeing has also developed aircraft corrosion prevention and control solutions that include utilization of less corrosion susceptible alloys, implementation of improved finish systems on magnesium drive system components and development of enhanced corrosion protection schemes that are applied to aircraft with a primary mission requirement in severe coastal or high humidity environments.
Boeing Global Services currently offers performance-based logistics (PBL) support and customer logistics support (CLS), including engineering, analysis, field service reps (FSRs), logistic service reps (LSRs), and support equipment. The PBL segment alone includes supply chain, AnalytX for fleet health monitoring, FSR, sustainment engineering, and publications.
The RSAF’s F-15SG fleet in Singapore and United States are now using the PBL and CLS service, as well as tailored support for six Apache operators in the Indo-Pacific region, such as Indonesia, Taiwan, and India.