user
Instruction
Answer the question based on the provided table.


Table
Table Title: Royal Bahamas Defence Force
Table Content:
| Aircraft | Origin | Type | In service | Notes |
| --- | --- | --- | --- | --- |
| Aero Commander 500 | USA | Light utility transport | 0 | 3 in service with the Air Wing from 1976 to 1990 |
| Beechcraft Super King Air 350 | USA | Light transport | 1 | in service since 2004 |
| Cessna 208 Caravan | USA | Light transport | 1 | in service since 2007 |
| Cessna 404 Titan | USA | Light transport | 0 | 1 in service with the Air Wing from 1991 to 2008 |
| Cessna 421C Golden Eagle | USA | Light transport | 0 | 1 in service with the Air Wing from 1988 to 2002 |
| Partenvia P.68 Observer | Italy | Light transport aircraft | 1 | in service since 2009 |
| Piper PA-31 Navajo | USA | Light transport | 0 | in service since 1993 |


Question
which transport has been in service the longest?


Answer Format
The final answer should be concise and use the following format:
```json
{
    "answer": [
        "answer1",
        "answer2",
        ...
    ]
}
```
rule
["Piper PA-31 Navajo"]