Reassuring to read the evidence for the depth of technical knowledge held by some posters, today.
The EC155B1 complimentary flight manual, section 7.5, page 2, has two tables. 1.2.1 is for standard tanks; 1.2.2 is for crash-worthy tanks.
Crash-worthy tanks were one of several special options fitted to all Bristow B1s, at the request of Shell, that mostly added weight. In this case it also reduced fuel capacity by approx. 41kgs. Some options, but not all, were later fitted to some other operator's B1s (such as external liferaft release). However, Bristow's 155s are probably unique as a result.
Another option that Shell required was eventually dropped before delivery. EC designed a mod for crash-worthy floors, but they were cancelled to prevent an extended delivery delay, and also as the final design was going to be very heavy. I expect the risk assessment was that fitting them would lose a passenger on every flight, so requiring more flights, leading to an overall increased exposure to incidents happening...
EDIT: For anyone who doesn't believe that Bristow's 155B1s have these tanks installed, just ask a CHC refueller at EHKD what's the most fuel they've ever been able to get in one, compared with everyone else's fleets. So much for comments such as "Crash-worthy tanks are not installed on any 155 flying commercial as per today" - total BS!
Last edited by mazdadriver; 8th May 2012 at 15:20.