"United's pretty close . . .he's a little high too . . . we might still get a little wake turbulence . . . I don't know, looks kind of close," the co-pilot nervously commented to the Captain.
   "Yeah, it's close, but I think we'll be OK," replied the pilot-in-command reassuringly.
Moments before, this crew of a Westwind jet was advised by approach control that they were "following a United Boeing jet on base two o'clock four miles southeast bound four thousand descending" into Orange County's John Wayne Airport. One of the Westwind crew acknowledged "in sight", and they were cleared on a visual approach to follow the larger jet.
   Not long after the co-pilot's timid words of warning, and the PIC's verbalization of an assumption without adequate foundation, the Westwind rolled inverted, and crashed into an Orange County neighborhood killing the five unfortunate souls on board.
   The crash made headlines for several reasons. First, it killed three chief executives from a major fast food chain. Second, it brought to the public's attention the insidious killer whirlwinds associated with Boeing 757 aircraft. The heirs of the passengers on the Westwind sued the owner/operator of the jet, which was being chartered for the evening flight. Settlements were entered into, and then the owner/operator (actually their insurance company which had paid the settlement funds) sued the United States Government, claiming the controllers were at fault, not the pilots.
   A United States District Court judge recently dismissed the case, finding the controllers were absolved of liability when the Westwind crew accepted the visual approach. (See, Management Activities, Inc. v U.S., (Sept. 16, 1998 C.D. Cal.) CV94-8313.)
   It is easy to become complacent when flying IFR. We are given altitudes to maintain, headings to fly, vectors to final, and traffic warnings. Why bother looking out the window? Better yet, why worry about wake turbulence. However, when flying under visual rules, even when entrenched in the IFR system, it is the pilot(s)' responsibility, not the controller's, to maintain adequate separation from other aircraft.
   The Aeronautical Information Manual (AIM), Section 4-4-10, describes IFR separation standards:

"(a)	ATC effects separation of aircraft vertically by assigning different altitudes; longitudinally by providing an interval expressed in time or distance between aircraft on the same, converging, or crossing courses, and laterally by assigning different flight paths.
(b)	Separation will be provided between all aircraft operating on IFR flight plans except during that part of the flight (outside Class B airspace or a TRSA) being conducted on a VFR-ON-TOP/VFR CONDITIONS clearance. Under these conditions, ATC may issue traffic advisories, but it is the sole responsibility of the pilot to be vigilant so as to see and avoid other aircraft.
(c)	When radar is employed in the separation of aircraft at the same altitude, a minimum of three miles separation is provided between aircraft operating withing 40 miles of the radar antenna site, and five miles between aircraft operating beyond 40 miles from the antenna site. These minima may be increased or decreased in certain specific situations."
AIM Section 4-4-13 VISUAL SEPARATION states in pertinent part:
"(b)	A pilot's acceptance of instructions to follow another aircraft or provide visual separation from it is an acknowledgment that the pilot will maneuver the aircraft as necessary to avoid the other aircraft or to maintain in-trail separation. In operations conducted behind heavy jet aircraft, it is also an acknowledgment that the pilot accepts the responsibility for wake turbulence separation.
Note: When a pilot has been told to follow another aircraft or to provide visual separation from it, the pilot should promptly notify the controller if visual contact with the other aircraft is lost or cannot be maintained or if the pilot cannot accept the responsibility for the separation for any reason.
AIM Section 5-4-20 VISUAL APPROACH states in pertinent part:
(d)	SEPARATION RESPONSIBILITIES: If the pilot has the airport in sight but cannot see the aircraft to be followed, ATC may clear the aircraft for a visual approach. However, ATC retains both separation and wake vortex separation responsibility. When visually following a preceding aircraft, acceptance of the visual approach clearance constitutes acceptance of pilot responsibility for maintaining a safe approach interval and adequate wake turbulence separation.
(f)	Visual approaches reduce pilot/controller workload and expedite traffic by shortening flight paths to the airport. It is the pilot's responsibility to advise ATC as soon as possible if a visual approach is not desired.

   During visual meteorological conditions it is common to have controllers issue, and pilots accept, visual approaches. At airports where large planes follow large planes, wake turbulence offers little to get excited about. But rare is the airport where there is not a mix of traffic. Most major metropolitan airports intermingle "heavy" jets with commuter turbo-props, business jets, and even single-engine General Aviation aircraft, such as my Debonair. Take, for instance, my regular flights to San Diego, California. This airport is known for its relatively short runway, steep approach over buildings, and finally, a jaunt over a multi-storied garage close to the approach end of the westerly runway. While there are other airports I could fly into in the San Diego area, Lindbergh Field is close and convenient to the downtown courts.
   I know what I am getting into, and plan accordingly. Often, I find myself wedged between two airliners, the one in front which invariably is a B-757. Here comes the dilemma: Follow too high, and the long landing may cause problems with the encroaching jet and an irate tower controller; Attempt to land on the numbers, and risk low level aerobatics. If the jet behind is too close, I will ask to be re-positioned in the pattern. Never will I knowingly descend at, or below the glide path of the jet ahead. My brother-in-law was flipped over at LAX while flying checks in a piston twin. He was very fortunate to have survived with minor injuries. I prefer not to tempt fate and end up in the same attitude as he.
   Thus, when flying IFR, and accepting a visual approach clearance, the ball's in your court. Controllers are no longer responsible for separation and wake turbulence avoidance. If you are uncertain as to where or at what altitude leading traffic is, decline the visual, and shift responsibility back with the controller.
In a recent article, I discussed assumption of the risk. Descending into an area where it is known, or should be known, that wake turbulence exists, is just that; an assumption of a known risk. Do so, and be prepared to pay the consequences.