Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the Tenure of the Officer who died in a helicopter accident with Badge/Serial Number 16805?

### Inputs:
table_name: table, columns: ['Rank', 'Badge/Serial Number', 'Tenure', 'Date of death', 'Cause of death']

### Response:
SELECT Tenure FROM table WHERE Cause of death = helicopter accident AND Badge/Serial Number = 16805