... does the Flight Path Vector display use air data at all or is it just inertial?
Embraer (Honeywell EPIC) uses both and the procedure is to ignore the FPA with unreliable airspeed.
Hi,
Seem's a little bit ironical ... but modern military jet fighters planes have an HUD with many interesting datas just in face of pilot eyes .. all this for assure the safety of one soul .. and some tons of metal and weapons .. and airliners have not this for assure the safety of hundred of souls and some tons of metal.
HUD just repeating what's available downstairs in the cruise so doesn't offer any enhancements when IMC.