The Honeywell HTF7250 (AS907-2-1G) propulsion engines are used on the Gulfstream G280 aircraft. It does not have mandatory scheduled overhauls or HSI (Hot Section) teardown inspections. Instead, it follows an on-condition maintenance program where the engine stays on wing until an issue arises during a scheduled inspection, an unscheduled event occurs, or an engine component reaches its life limitation. This makes budgeting engine maintenance costs more challenging, unless the engines are covered under a maintenance service program such as Honeywell’s MSP program.
Inspection requirements for the AS907-2-1G engine are listed in Chapter 5 of the applicable Airframe Maintenance Manual, Maintenance Review Board (MRB) Report and Engine Maintenance Manuals (MM).
Below is a summary of the more significant inspection requirements and applicable SBs (Service Bulletins). Please note that Chapter 5 of the applicable Airframe and Engine MMs should be consulted when determining engine maintenance requirements, and the below information should be considered reference only.
1A and 500 Hour
The Engine MM 500 Hour (table 8004) and the Airframe MM 1A engine-related items have the same information.
Note The Difference:
The Engine MM has a two-year inspection interval for the Engine Fuel Filter Mechanical Differential Pressure Indicator.
2A and 1000 Hour
Both the Airframe and Engine MMs state an oil change.
Note The Difference:
The Engine MM (table 8005) specifically states the oil filter.
Airframe MRB Manual lists the filter as a 2A item.
This requirement has been superseded by SB AS907-72-9084 that puts the interval for the oil filter change and analysis at the 150-250 hour interval.
4A and 2000 Hour
Airframe MM
Engine MM
Required during the 2000 hour (table 8007) inspection:
Note The Difference:
The Airframe MM specifically states blades and the blade discourager. The Engine MM only states the blade discourager.
8A and 4,000/4,800 Hour
In both the Engine and Airframe MMs the requirement to move from the 8A/4000-Hour to the 4800-Hour (table 8008) interval with the following SBs are required:
Several of the tasks for the 8A and 4,800 Hour (Table 8009) between the Airframe and Engine MMs are the same.
Note The Difference:
The Engine MM states restoration of the Main Fuel Nozzles.
The Airframe MRB Manual lists these along with most of the other Engine MM requirements.
Honeywell does have a special program for replacement of the #4 bearing for SBs AS907-72-9045 and AS907-72-9080 at the 4200- or 4800-hour inspection, as applicable. MSP does cover this cost, but at a discounted amount for engines not on the program.
7,000 Hour
The Engine MM (table 8010) requires the HMU (Hydro Mechanical Unit) be removed, disassembled, cleaned, assembled, and tested at 7000 hours of operation. This is also listed under 14A in the Airframe MRB manual.
Note The Difference:
This is not referenced in the Airframe MM.
16A and 9600 Hour
According to the Airframe MM & MRB, SB 72-9055 is required to move the Compressor Zone Borescope from the 16A to the 9,600 Hour interval. Engine serial numbers P-130168 and subsequent had this bulletin incorporated at engine build.
Note The Difference:
The Engine MM does not list SB 72-9055 as a requirement for the 9600 hour interval.
Comparing Aircraft Maintenance Quotes: Avoiding Sticker Shock
The Importance of Market Research When Buying and Selling a Private Jet
Using Engine Condition Trend Monitoring As A Standard
Expert Tips for Buying and Selling Business Aircraft: Maximizing ROI and Market Insights
The Importance Of Proper Business Jet Engine Preservation