Abstract: Apparatus, systems, and methods that include a variable length linkage for connecting together tie rods. The linkage includes first, second, and third apertures. There is a first distance between the first aperture and the second aperture and a second distance between the first aperture and the third aperture. The apparatus may include a fourth aperture having a third distance between the first aperture and the fourth aperture. The second, third, and fourth apertures may each have a non-circular cross-section. The linkage may include a base, a first finger, a second finger, and a third finger that each extend from the base. The first aperture may be in the base, the second aperture may be in the first finger, the third aperture may be in the second finger, and the fourth aperture may be in the third finger. The first aperture may be oriented vertically with the other apertures oriented horizontally.

Abstract: Apparatus, systems, and methods that include a variable length linkage for connecting together tie rods. The linkage includes first, second, and third apertures. There is a first distance between the first aperture and the second aperture and a second distance between the first aperture and the third aperture. The apparatus may include a fourth aperture having a third distance between the first aperture and the fourth aperture. The second, third, and fourth apertures may each have a non-circular cross-section. The linkage may include a base, a first finger, a second finger, and a third finger that each extend from the base. The first aperture may be in the base, the second aperture may be in the first finger, the third aperture may be in the second finger, and the fourth aperture may be in the third finger. The first aperture may be oriented vertically with the other apertures oriented horizontally.

Abstract: An airworthiness certification system employs a digital public ledger (DPL) that records compliance with all regulatory requirements that must be met to obtain and/or maintain airworthiness certification. When a user verifies compliance with a regulatory requirement, the user generates a digital compliance record containing certification data indicating compliance with the regulatory requirement and a cryptographic signature of the user. The digital compliance record is recorded in a digital public ledger by generating a new transaction block in the DPL containing the digital compliance record and cryptographically linking the transaction block with a previous transaction block in the DPL.