Personnel is frequently used by the press in India even when referring to a single person, particularly if he belongs to the armed forces (see the examples below). This is an error since personnel is plural. Serviceman can often be an appropriate substitute in cases where the rank of the person is not known.
1. It was unfortunate that an army personnel posted at a high altitude field area who met with an accident while at duty was granted a meagre pension. (www.judgementstoday.com)
2. On Tuesday night, one terrorist and an army personnel along with a civilian were killed in another gun battle in the area. (www.ibnlive.com)
3. The other argument of the police was that the service rules did not permit grant of out-of-turn promotion more than twice in the career of a police personnel. (www.hinduonnet.com)
In the first two examples, serviceman would have served the purpose and in the third one policeman would have been perfect.