Question: An American twin-engine attack helicopter that was developed for the United States Marine Corps as part of the H-1 upgrade program is also called what when based on the ICAO phonetic alphabet pronunciation of it's variant letter? 
Sentence (from "Bell AH-1Z Viper"): The AH-1Z, one of the latest members of the prolific Huey family, is also called "Zulu Cobra", based on the military phonetic alphabet pronunciation of its variant letter.
Relevant evidence: Yes