The only reason that we persevere with the TriStar is because of the military modifications that it has. If we want chater (and we do - buckets of it for both freight and pax) then we go to the market and get the cheapest deal that falls into the 'vaguely reliable' bracket. Recent events suggest that safe and competent operation of the aircraft is optional for freight charter.
Strangely, we don't start from the premise that we must have another old knackered TriStar to supplement our fleet of knackered TriStars when they don't work and then trawl the market accordingly. So 411, doubt whether any of our senior blokes want to talk to your sales chappie unless you are also doing a nice line in something a bit newer.