Call AST® for on-the-spot support

~From borescope inspections to complex modifications, from
scheduled maintenance events at your site to emergency overnight
repairs: the range of services offered by AST® Engines experts
includes a comprehensive array of tasks with two simple goals:

• to extend the service life of your engines
• to avoid costly shop visits

When you employ the global on-site support of AST® Engines
experts, you benefit from the extensive know-how of Lufthansa
Technik Engine Services – the world's leading independent engine services provider. Our specialized teams will fly at short notice to any destination in the world, and carry out all required work on site. You benefit from innovative, proprietary repair procedures that are durable, cost-efficient and reliable. 

An exemplary case for the AST® Engines solution
In normal operation, the variable stator vane (VSV) bushings on a number of CFM56 engine types start to show signs of wear at 16,000 to 20,000 operating hours. Since inspection is not required before the 24,000 hour limit, the consequences can be drastic – at worst, they can result in an
in-flight shutdown (IFSD).
To prevent this and avoid a shop visit at the same time, Lufthansa Technik's Airline Support Team (AST® Engines) has developed a procedure to replace the inner and outer bushings on-site at
the aircraft location and at the customer's discretion.
With the engine removed, the VSV bushings are replaced together with the damaged shrouds and seals in a procedure that takes the team at most four days. The work can be carried out during a suitable layover, for example, a C-check. 
This preventive measure gives the customer not only an extra EGT margin of six to eight degrees Celsius but also the chance that the engine can be used for its entire potential life. Depending on the respective operator's flight profile, the CFM56 engine has an on-wing life of no less than 30,000 hours.

Keep them running
Lufthansa Technik's AST® Engines experts offers a unique advantage: the ability to provide engine repairs at the site of the aircraft, saving the customer the time and expense usually associated with a shop visit. While some repairs require that the engine be removed from the aircraft, many are possible with the engine on-wing, which helps you cut costs and downtime even more. But whether on-wing or off-wing, all repairs performed by the AST® Engines experts have one thing in common: They are a highly efficient means of keeping the engine running and achieving a longer time on-wing with the level of safety and dependability that customers have come to expect from any engine Lufthansa Technik handles.

On-wing repair

On-site repair

Fan disk replacement
The fan disk life may be different from the booster spool life and may require premature replacement. For this reason, it can become the driver for the shop visit.

One possible reason: during an on-wing inspection, the technician discovers that fan disk dovetail inspection limits have been exceeded. Lufthansa Technik can perform the necessary replacement on-wing, avoiding a shop visit and the coordination and expense this involves.

Fan abradable material replacement
In cases of severe foreign object damage (FOD), wear and tear or exceeded fan tip clearance, the fan abradable liner (rubber) of CFM56 engines can be replaced on-wing. Since it is essential that there be no other findings that might affect the engine, a detailed description of the findings should be provided prior to scheduling AST® Engines experts.

The AST® Engines experts can perform the job in about three days, including initial reparations, removal of the spinner, replacement and machining of the abradable liner, and reinstallation of all parts.

LPC replacement
Replacing the low pressure compressor (LPC) is normally a shop load event necessitated by foreign object damage (FOD) or by reaching a flight cycle limit. For engines of the CFM56 family as well as the CF6-80, Lufthansa Technik's AST® Engines experts can perform a complete booster exchange during two shifts within a single day, including preparation time.

This means the aircraft is grounded for only 24 hours. Since the scheduling for this work is handled flexibly by the AST® Engines experts, the loss of productivity can be reduced to an absolute minimum.

Air/oil seal change
A delaminated bearing No. 3 air/oil seal often leads to premature engine removals. If this seal has been identified as the source of a fault, such as the smell of oil in the cabin, it must be replaced.

Lufthansa Technik's AST® Engines experts can help you avoid a shop visit: working in a two-shift system, the seal exchange is completed on-site within four days. The engine must be removed from the aircraft prior to AST® Engines experts starting their work, but beyond that the team needs only electrical power and a crane to finish the repair.

Bearing unit replacement
The fan shaft can limit the life of your engine and thus become the source of many repairs. The No. 1 bearing stationary air/oil seal may require replacement if oil in the booster spool has been identified as the reason for the smell of oil in the cabin.

Lufthansa Technik's AST® Engines experts will perform the replacement of the bearing unit on-wing.

HPT blade exchange
There are many reasons why CFM56 engines may need their high pressure turbine (HPT) blades replaced. Depending on the cause, either single blades or the entire set may have to be exchanged. The AST® Engines experts can do this on-site. In order to lower the risk of additional findings, a full borescope inspection should be performed before removing the engine. Should any additional findings surface, the mobile AST® Engines experts can provide additional support to avoid a shop load event.

Fuel nozzle replacement
Fuel nozzle coking is a familiar problem; it occurs if the burner staging valve is still active (i.e. cut-off of 10 out of 20 fuel nozzles at low thrust operation). CFMI and nozzle manufacturer Parker Hannifin has been investigating fuel nozzle-induced LPTN distress/LPT blade failures since 2006. Most failures can be traced to compression set in o-rings, causing high out-of-spec fuel flow at low fuel pressure. This o-ring deterioration occurs predominately on CFM56-7B engines.

Lufthansa Technik is able to identify the coked nozzle and can perform the necessary repairs at the engine on-wing.

VSV bushing
The variable stator vane (VSV) bushings on certain CFM56 engines start to show serious signs of wear well before the 24,000 hour inspection limit. To prevent damage while at the same time avoiding a shop visit for the affected engine, Lufthansa Technik has developed a special maintenance procedure: the inner and outer bushings are replaced on-site at the aircraft location. This preventive measure gives the customer an extra EGT (exhaust gas temperature) margin and the chance to make the most of the potential life of the aircraft's engine and avoid any further VSV interval inspection on the effected engine.

Top casing
If high pressure compressor (HPC) blades are damaged beyond the blend limits in the Engine Shop Manual (ESM), affected blades can be replaced using a top case procedure. This process usually requires a shop visit, but the AST® Engines experts can perform the job on-site.

To ensure that the team has all necessary replacement blades available, the number of damaged blades per stage must be stated. With a turnaround time of two to four days, the replacement of damaged HPC blades is a highly efficient solution.

Call us now:

If you would like more information about the service portfolio of AST®, please contact us with your specific requirements.

Cell Phone: +86-186-1710-7730
Email Address:  engine.services@lht-shenzhen.com  

AST® capability list:

CFM International
• CFM56-5A
• CFM56-5B
• CFM56-5C
• CFM56-7B

General Electric
• CF6-80C2

Pratt & Whitney
• PW4000

• V2500

• Trent 500
• Trent 700
• Trent 900

AST® Engines worldwide
With its Airline Support Team (AST® Engines), Lufthansa Technik has achieved an excellent reputation in the aviation industry for performing highly efficient engine repairs at the customer's premises. And since the affected engines can often be kept on-wing, aircraft ground times are even shorter and cost effectiveness even greater.

There's an AST® Engines experts team located in every part of the globe:

• Europe (Frankfurt, Germany)
• North America (Montreal, Canada)
• South America (Buenos Aires, Argentina)
• Africa (Johannesburg, South Africa)
• Asia (Hong Kong and Shenzhen) 

VSV Bushing
Customer advantages

• 4 days TAT (engine removed)
• Performance improvement
• Longer on-wing operation
• No spare engine required
• Highly cost-efficient
• Shop visit costs will be postponed
• No waste of life at core LLPs