---
type: project
venture: halcyon
status: active
outcome:
owner: Dmitri Sokolov
due:
updated: 2026-09-23
---

# Mk3 — shaft runout, not the bearing

<!-- src: Atlas/ventures/halcyon/VENTURE.md, split out 2026-09-23 under ADR-31 -->

**Why this is a project and not a paragraph.** It has its own owner, its own
evidence, its own open questions with a P0 on them, and **two other projects are
downstream of it** — [[cascadia-contract]] is blocked on it through `hobbs-po6`,
and [[do-160-certification]]'s eight-month number was costed against the failure
this project says is the wrong one.

## State

**Dmitri is confident it is not the bearing.** Rowan, Monday 14 September, from
the 07:00 conversation in the test cell:

> "He's been running shaft runout tests on his own time for a fortnight and he's
> now confident it isn't the bearing — he wants to bring it to Priya formally
> this week."

**A fortnight of testing on his own time**, which began before the 7 September
conversation in which the theory first reached Rowan.

Before that, 7 September, in Rowan's words:

> "Dmitri's thing on the bearing. He doesn't think it's the bearing. He thinks
> it's shaft runout and the bearing is just where it shows up, which — if he's
> right that's a different failure and it changes the whole DO-160 schedule, and
> I need to not say that out loud to anyone until he's sure."

## What is known, and what is not

| | |
|---|---|
| **Known** | He is confident it is not the bearing, after a fortnight of his own tests |
| **Not recorded** | What would **formally confirm** runout |
| **Not recorded** | **How many days** that takes |
| **Not recorded** | Whether anything he has already run counts as confirmation |

**Those three are `hobbs-62a`, P0**, and they are the reason the chain beneath
this project has not moved. **"This week" was Dmitri's own commitment, made in a
week that ended Sunday 20 September.**

## The constraint

**`HAL-01`** — nothing about this reaches Marcus until Rowan lifts it. Whether it
covers Priya is unanswered: `hobbs-9xk`. Full record in
`Atlas/ventures/halcyon/decisions.md`.

## Tasks

| | | |
|---|---|---|
| `hobbs-62a` | **P0** | What confirms or rules out runout, and in how many days |
| `hobbs-9xk` | P1 | Does the hold cover Priya, before Dmitri takes it to her |
| `hobbs-po6` | P1 | Blocked on `hobbs-62a`. Does the answer move the Cascadia witness point |
| `hobbs-9fb` | P2 | Rig state into a file Priya can read without Dmitri |

## The single point of failure, unaddressed

**Mk3 rig state lives in a spreadsheet Dmitri maintains and in Dmitri's head —
mostly the head.** Recorded on day one, unchanged since. `hobbs-9fb`.

## People
[[Dmitri Sokolov]] · [[Priya Raghunathan]]