The most common and most likely answer to this crossword clue is the 9 letter word FAIL-SAFE
I've seen this crossword clue in Independent
F
A
I
L
-
S
A
F
E
More clues leading to the result FAIL-SAFE
Buddy explains!
The straight part
We know that "protection component" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case protection component = fail-safe.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does FAIL-SAFE mean?
FAIL-SAFE noun- A device, mechanism or measure designed to make something fail-safe.
- To compensate automatically, in the event of a failure.
- To make a device or mechanism fail-safe, or to add a fail-safe device or mechanism to an existing system.
- That does not cause undue damage in the event of failure.
- Designed to shut off for safety if an emergency occurs.