On November 7, 2007, the Hong Kong-registered, 901-foot-long containership M/V Cosco Busan allided with the fendering system at the base of the Delta tower of the San Francisco–Oakland Bay Bridge. Contact with the bridge tower created a 212-foot-long by 10-foot-high by 8-foot-deep gash in the forward port side of the ship and breached the Nos. 3 and 4 port fuel tanks and the No. 2 port ballast tank. As a result of the breached fuel tanks, about 53,500 gallons of fuel oil were released into San Francisco Bay.
1 | Incident snapshot
| Impact time (LT) | 08:30 |
| Visibility | < 0.25 nm (heavy fog) |
| Speed on impact | ≈ 10 kn |
| Key human factor | Pilot mis-identified two lateral buoys as mid-span and remained on a diverging heading |
| Cognitive backdrop | NTSB found the pilot’s performance was degraded by multiple prescription drugs (modafinil, lorazepam, hydrocodone, sertraline, …) that can diminish alertness and judgment |
| Consequences | 212 ft × 32 ft hull gash, ≈ 53 000 gal HFO spill, > USD 70 m direct cost |
2 | Human-factor timeline
| Time | Bridge dialogue / action | Issue surfacing |
|---|---|---|
| 08:22 | Pilot: “This is the centre of the bridge, right?” – Master: “Yes.” | First sign of loss of awareness |
| 08:25 | Orders full-ahead + starboard 20° while track already diverging | Growing confusion |
| 08:27 | VTS: “COG 235°.” – Pilot: “I’m steering 280°” (actual 262°) | Confusion confirmed |
| Helm commands flip hard-STBD → mid → STBD 20 → hard-STBD; voice pitch climbs | Erratic decisions | |
| 08:30 | Port bow strikes bridge fender | — |
The pilot’s reduced cognitive margin—linked to his medication regimen—meant these escalating cues went unrecognized in real time.
3 | Helm Order Monitor cues
| Visible cue | Trigger (internal logic withheld) | Appearance | Where it would fire here |
|---|---|---|---|
| Orange awareness icon (silent, bottom-left) | Early drop in Overall Awareness Score | Lights orange | After the “centre of bridge?” exchange (≈ 08 : 22) |
| Red banner “ALERT: AWARENESS IMPAIRED” + short buzzer | Overall Awareness Score below critical | Full-screen red | When helm commands oscillate (≈ 08 : 27 : 45) |
No controls are locked; acknowledgements are not required—HOM remains decision support only.
4 | Alternate sequence with HOM active
| Time | HOM cue | Likely crew action | Outcome |
|---|---|---|---|
| 08:22:05 | Orange icon | Master re-checks alignment; pilot realises buoys ≠ centreline | Course corrected early |
| 08:27:45 | Red AWARENESS IMPAIRED banner | Master slows to half-ahead, takes con, orders port 10° | Track re-aligned mid-span |
| 08:29:30 | Banner clears as awareness score recovers | — | Vessel passes safely beneath span |
| 08:30 | (Impact in reality) | — | Allision averted |
5 | Benefit at a glance
- 3-minute intervention window between first icon and would-be impact.
- Slowing to 8 kn and correcting heading restores > 60 m clearance.
- Avoids > USD 70 m damage, oil-spill clean-up, legal penalties.
6 | Why two simple cues are enough
- Progressive signalling – orange prompts review; red demands immediate focus.
- Plain English – “AWARENESS IMPAIRED” is instantly understood, even under stress.
- Crew stays in command – no UI lock-out, no forced ACK.
- VDR logging – alerts time-stamp cognitive degradation for post-event learning.
Take-home message
The Cosco Busan pilot’s situational awareness—already thinned by prescription medication—collapsed in the fog. Helm Order Monitor’s early orange icon and decisive red “ALERT: AWARENESS IMPAIRED” banner would have surfaced that hidden risk, buying the bridge team precious minutes to slow down, verify position, and steer clear of the bridge.
