There are 10 attributes to a search pattern and one of them is that the search must start at a known point, stop at a known point and cover a known area. Another attribute is that the pattern allows for communication between the diver(s) and top side personnel.
When a diver looses contact with personnel on the surface or with his dive partners, the Grim Reaper is likely to strike and take the life of a teammate, husband, father, friend, etc.
Ron Siver was a PSD killed in 1984 during a sled operation (out of air and a "J" valve were contributing factors). Donald Shultz was a PSD (May 2004), Mark Miller (March 2004), Paul Jolliff (June 2002), J. C. Smith (June 2000), Bryan Pottberg (1999) were all PSD line of duty deaths where a lack of communications was a common denominator cited by investigators.
The NFPA understands that a lack of communications between divers and top side personnel are necessary in assuring diver safety and that is why a means of "electronic communications" is a requirement for public safety divers.
While underwater sleds have proven themselves to be helpful tools in some ideal conditions, the conditions "DivingFirefighter" describes sound less than ideal.
Certainly this dive operation was not within the guidelines established by the NFPA and I am optimistic that many teams may have done things differently. While I do not like to second guess the decision made by a team leader, I would privately like to discuss how things could have been done to assure diver safety and with a higher degree of success.
Diving with a poor last seen point is a bad scenario but having a line of duty death and planning a departmental funeral is far worse, especially when a "risk/benefit factor" is considered (a recovery dive).
Inexpensive SONAR systems have proven to be an effective tool. If a team cannot purchase one, they should work to learn who in their region owns one. In this case, and without the benefit of knowing all of the facts, I think I would have called for a SONAR before deploying divers without comms, in limited vis, on sleds.
The IADRS has helped several teams acquire grant money for SONAR systems and if you need some help, consider visiting:
http://www.diverescueintl.com/Events_and_Grants.aspx
Fraternally,
Blades Robinson