If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).




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SCHEDULE 13D




Comment for Type of Reporting Person:
Row 13. Based on 31,310,209 shares of Common Stock outstanding as of April 3, 2026, as disclosed in the Issuer's prospectus supplement filed on May 11, 2026 pursuant to Rule 424(b)(5) under the Securities Act.


SCHEDULE 13D




Comment for Type of Reporting Person:
Row 13. Based on 31,310,209 shares of Common Stock outstanding as of April 3, 2026, as disclosed in the Issuer's prospectus supplement filed on May 11, 2026 pursuant to Rule 424(b)(5) under the Securities Act.


SCHEDULE 13D




Comment for Type of Reporting Person:
Row 13. Based on 31,310,209 shares of Common Stock outstanding as of April 3, 2026, as disclosed in the Issuer's prospectus supplement filed on May 11, 2026 pursuant to Rule 424(b)(5) under the Securities Act.


SCHEDULE 13D




Comment for Type of Reporting Person:
Row 8, 10 and 11. Includes 375,420 shares owned directly by Lightship Capital LLC ("Lightship"). As described in Item 2 herein, each of AIP Fund VI, Vertex Funding, Vertex Holdco and Lightship are under common control of AIPCF VI, LLC ("AIP GP" and, together with AIP Fund VI, Vertex Funding, Vertex Holdco and Lightship, the "Reporting Persons"). Row 13. Based on 31,310,209 shares of Common Stock outstanding as of April 3, 2026, as disclosed in the Issuer's prospectus supplement filed on May 11, 2026 pursuant to Rule 424(b)(5) under the Securities Act.


SCHEDULE 13D




Comment for Type of Reporting Person:
Row 13. Based on 31,310,209 shares of Common Stock outstanding as of April 3, 2026, as disclosed in the Issuer's prospectus supplement filed on May 11, 2026 pursuant to Rule 424(b)(5) under the Securities Act.


SCHEDULE 13D


 
American Industrial Partners Capital Fund VI, L.P.
 
Signature:By: AIPCF VI, LLC, its general partner By: /s/ Stan Edme
Name/Title:Stan Edme, Managing Member and VP
Date:05/12/2026
 
AIPCF VI Vertex Aerospace Funding LP
 
Signature:By: AIP Vertex GP LLC, its general partner By: /s/ Stan Edme
Name/Title:Stan Edme, Managing Member and VP
Date:05/12/2026
 
Vertex Aerospace Holdco LLC
 
Signature:/s/ Joel M. Rotroff
Name/Title:Joel M. Rotroff, President
Date:05/12/2026
 
AIPCF VI, LLC
 
Signature:/s/ Stan Edme
Name/Title:Stan Edme, Managing Member and VP
Date:05/12/2026
 
Lightship Capital LLC
 
Signature:/s/ Stan Edme
Name/Title:Stan Edme, VP
Date:05/12/2026