Gallery: Inside Aspire MRO’s Boeing 777 PTF Conversions

Aspire MRO launched in 2022 to perform Boeing 777 passenger-to-freighter (PTF) conversions and maintenance for its partner, Mammoth Freighters. Aviation Week Network recently visited the company’s Fort Worth, Texas facilities to get a look behind the scenes as Aspire ramps up work ahead of Mammoth Freighters’ anticipated PTF supplemental type certificates (STC).

According to Eric Castillo, vice president of customer service and support at Aspire MRO, the facility is one of the largest cantilevered hangars in North America. The 900,000 ft.² hangar is part of a nearly 1 million ft.² campus.

From end-to-end, the six-bay hangar stretches a quarter mile. Pictured here is a long hallway that runs the entire length of the hangar.

Two of the six hangar maintenance bays are fully automated. Aspire MRO CEO Phil Bathurst says the company can “pull a 777 in the hangar, and within 5 minutes it’s totally encapsulated. You pretty much can work the aircraft without a ladder.” 

The facility, which was originally developed by American Airlines for heavy maintenance, can hold six 777s, and up to 15 aircraft on its outdoor ramp space. Each bay features an overhead crane, and the facility also has pneumatics installed throughout. “When American developed the place, they did a heck of a job,” Bathurst says of the hangar’s utility.

During Aviation Week Network’s visit in October, Aspire MRO had five 777-200s and one 777-300 in the process of various conversion and maintenance work. In 2025, Bathurst expects the company to have five production lines running.

Customers for Mammoth Freighters’ 777 PTF conversions so far include DHL, which has ordered 11, and Avia Solutions Group, which has ordered six. Including other undisclosed customers, Mammoth has approximately 35 orders and “interest is mounting,” says Brian McCarthy, vice president of marketing and sales at Mammoth Freighters.

Aspire MRO worked with ModTruss to design custom work platforms for the facility. “They’re hydraulically driven. They do all the right things,” says Bathurst. “We can put 30 guys to work at three different levels.”

While the facility has plenty of room for back shops, Aspire MRO is currently outsourcing certain tasks such as composite work and non-destructive testing. Bathurst says that as Aspire grows and evolves, it will look at bringing that work back in-house. Pictured here is Aspire MRO’s floor beam shop.

As part of the cargo conversion process, Aspire MRO is taking old carbon fiber floor beams out of the 777s and switching to aluminum beams to accommodate cargo weight. For a 777-200, Castillo says this entails installing around 68 beams.

Aspire MRO also removes commercial interiors from aircraft as part of the conversion process. These parts are sold or disposed of by Mammoth Freighters and its partners. Mammoth is also working on recycling unused aluminum. 

When engines come off the 777s as part of the conversion process, Castillo says they often go to one of Aspire’s engine MRO partners for maintenance work and checks. While Aspire MRO is considering adding more heavy maintenance capabilities, it is currently focused solely on the 777 P2F work for Mammoth Freighters.

Support beams holding up a 777’s fuselage as it undergoes conversion work.

McCarthy says Mammoth Freighters is producing cargo doors at a high rate, with full capability of producing up to 24 annually. 

When Aspire MRO first launched, it had around 30 employees. By the beginning of 2024 it had just under 100 employees, which has ramped up to around 500. Bathurst says he is aiming to reach 700 employees as the facility increases its conversion pace.

Aspire MRO is completely paperless and uses EmpowerMX software to manage maintenance processes digitally. Each mechanic has been issued a tablet. “It’s signed out and you’re responsible for it. We started initially with cabinets that were very expensive to charge [the tablets], and everybody would complain because it wasn’t theirs, so now it’s theirs,” says Bathurst. “They’re taking care of [the tablets], and with 500 guys, we’ve only had one [tablet] break. It’s been pretty incredible, because that was the concern.”

According to McCarthy, Mammoth Freighters expects to have full hangars in 2025 as it finishes its STCs for the 777-200 and -300. Once those are complete, he expects the company to be able to produce around 20 777 freighters annually between Aspire MRO’s facility and its production lines at STS Aviation Services in Manchester, UK.