HFCE stands for Honeywell Flight Control Electronics. HFCE is a Point-to-Point Data Bus Protocol deployed in several applications within the 787 Flight Control Electronics (FCE) System.

This implementation of HFCE supports the FCE Direct Mode Rate Sensors (DMRS) Buses. The FCE DMRS Buses are dedicated broadcast 400 Kbit/second links from the sensor package to system ACEs.

HFCE packet structure

In HFCE, all transmissions are in packets.

Basic packet format

Each packet consists of the following fields (transmission sequence MSB bit first).

Preamble Sync	Label	Length	Data	FCS	Postamble
Min. 10.5 bit times	16 bit	16 bit	0 to 62 16-bit words	16 bit	Min. 4 bit times

Label, Length and Data fields are specified by the user, the IPM-HFCE module will add the Preamble, FCS and Postamble fields, if desired.