Conversation so far:
What caused Indian actor Jayan's death?
On 16 November 1980, Jayan was killed in an accident on the set of the movie Kolilakkam.
Where was the movie Kolilakkam set?
Kolilakkam was filmed in Sholavaram, near Chennai, Tamil Nadu.
Who was starring in the movie Kolilakkam with Jayan?
Madhu, Sukumaran
What caused the accident that killed the actor Jayan?
Jayan was performing a dangerous stunt that involved him boarding an airborne helicopter.  The helicopter lost its balance and crashed along with Jayan who was hanging onto the landing skids.
Was anyone else hurt in the accicdent that killed the actor Jayan?
The pilot and his co-star Balan K. Nair, who was in the helicopter, survived with minor or no injuries.
Did Jayan have any family at the time of his death?
Jayan's mother Bharathiyamma became bedridden after this incident, and she too died two years later.

Question: Was there any controversy about his death?
Self-contained rewrite: Was there any controversy about Jayan's death?