E-6B Mercury
ICAO E6The aircraft that talks to submarines, trailing a five-mile antenna. Live E-6B Mercury positions.
Flying right now
Live · 30s
No E-6B Mercury is transmitting ADS-B at the moment.
Military aircraft are not obliged to broadcast, so this happens regularly. The count refreshes every thirty seconds.
Airframe
- Manufacturer
- Boeing
- Role
- Airborne command post and submarine communications
- Class
- L4J — Landplane, 4 jet engines
- Crew
- Up to 22
- First flight
- 19 February 1987
- In service
- 1989
Operators airborne
Nothing of this type is up right now.
About the E-6B Mercury
The E-6B does two jobs that both matter enormously and neither of which is visible from outside. It relays orders to submerged ballistic missile submarines using very low frequency radio, and it serves as an airborne launch control centre able to command land-based missiles if ground facilities are gone.
The submarine communication works by trailing a wire antenna several miles long behind the aircraft and flying tight circles so that the wire hangs almost vertically downward. A tracker watching an E-6B orbit very slowly in a small circle for hours is watching exactly that.
Sixteen exist, based on the Boeing 707 airframe, and they transmit ADS-B often enough that their movements are followed closely.
Callsign prefixes
- GOTO
- A long-standing E-6B block
- IRON
- Frequently seen on Mercury sorties
How to recognise it
- —A 707 airframe with four engines and a wingtip pod on each side.
- —Numerous blade aerials and a distinctive fuselage-top fairing.
- —On the feed: extremely tight, slow orbits held for hours — the trailing wire antenna at work.
Common questions
+ How does an aircraft talk to a submerged submarine?
Very low frequency radio, which penetrates seawater. The E-6B trails a wire antenna several miles long and flies tight circles so the wire hangs nearly vertically, which is what makes the transmission work.
+ What is TACAMO?
Take Charge And Move Out — the name of the mission the E-6B performs, maintaining communication with the ballistic missile submarine fleet under any circumstances.
+ Is the E-6B the same as the E-4B?
No. Both are airborne command posts, but the E-4B is a 747 serving the national command authority, while the E-6B is a 707-based Navy aircraft focused on submarine communications and missile launch control.