The incident happened about 1.20pm on Saturday (22 August) and the road is currently closed in both directions between the A2025, near Lancing and A293, near Shoreham-by-Sea.
The emergency services, the Air Accident Investigation Branch (AAIB) and Highways England are continuing to work together to deal with the incident.
A police and AAIB investigation is being carried out at the scene. Following this Highways England will need to carry out repairs to the damaged road. Drivers will be advised once it is safe to re-open the road.
Drivers are advised to avoid the area if possible. Where they cannot, those travelling westbound are advised to exit the A27 before the closure at the A283 junction and join the A283 north towards Washington, join the A24 south and re-join the A27 following the hollow black triangle symbol.
Those travelling eastbound should exit the A27 before the closure at the A24 junction, join the A24 north towards Washington, join the A283 south and re-join the A27 following the hollow black diamond symbol.
This diversion route is in place due to an exclusion zone around the incident and drivers following it are advised to allow plenty of extra time for their journeys.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.