Miami-based Aeronautical Engineers, Inc. (AEI) has launched a new B737-900ERSF Passenger-to Freighter conversion program. AEI is a Boeing licensed third-party provider of Supplemental Type Certificates and the new B737-900ERSF program is covered under this STC licensing arrangement. The granting of flight approval by Washington’s FAA is scheduled for 2029, with European regulator EASA and China’s CAAC due to follow suit shortly after.

Although it is still a long way to go until the first B737-900 P2F freighter takes to the skies, AEI management does not reveal whether the retrofitter already has a launch customer for its first B37-900 conversion, and if so, which operator it is.
Boeing’s preferred retrofitter
Instead, AEI emphasizes the merits and performance data of the future B737-900 Extended Range Special Freighter (ERSF). It will be the very first passenger-to-cargo converted B737-900ERSF and become AEI’s largest and most capable narrowbody conversion freighter. The B737-900ERSF offers unmatched volume and payload advantages over existing B737 freighter platforms, the company emphasizes in a release. AEI is well placed to judge, as it is Boeing’s preferred converter, having already turned many other Boeing B737 passenger variants into freighter aircraft, giving them a second life in service to air cargo.
First flight is scheduled for 2029
According to the company, the first B737-900ERSF will offer the cargo industry a loading capacity of 26,173 kg (57,700 lbs.) per take-off- or, in the case of volume cargo, 207 m³ (7,273 ft³). The aircraft offers twelve 88”x125” main deck pallet positions and is equipped with a reinforced floor structure to support high-density freight and e-commerce packages.
AEI is aiming to achieve FAA Supplemental Type Certification (STC) in 2029, with EASA and CAAC approvals scheduled to follow.
“This is a strategic move to address the increasing demand for higher capacity narrowbody freighters,” said Robert T. Convey, AEI Senior Vice President of Sales and Marketing. “With the global e-commerce and express markets continuing to grow, the B737-900ERSF will provide operators with the right blend of payload, volume, and economics.”
Broad customer base
With over 625 freighter conversions delivered to date, the vast majority of which are Boeing aircraft, AEI continues to set the standard in conversion reliability, program performance, and customer service – especially regarding the different narrowbody variants of the B37 series.
In addition to Boeing jetliners, aircraft from Canadian manufacturer, Canadair, are also included in the retrofitter’s portfolio, such as the CRJ900 and CRJ200.
Customers include well-known names in air freight as well as niche providers such as Allied Air from Nigeria, Serve Air from the Democratic Republic of Congo, and Bulgaria’s CargoAir.
Boeing’s archrival, Airbus, has its own converter for retrofitting the group’s jetliners: Dresden, Germany-based Elbe Flugzeugwerke (EFW). ST Aerospace from Singapore holds a majority stake in the company (55%), while 45% capital share belong to frame maker Airbus.




