When outbound from an IAF on an approach to a procedure turn, may the pilot choose whether to use time or distance?

Question

I was trained that if a fix to be flown over and then outbound for an approach is off-airport, then fly out for 1 minute prior to making a procedure turn. If it is over the airport, then fly outbound for 2 minutes instead of 1.

Would it also be proper to simply decide on a minimum distance to be flown such as 5NM outbound from the fix as long as it is within the published maneuvering area for the procedure such as 10NM from the IAF?

I know the times are only guidelines, but basically, what I am asking is would not using time at all and simply using DME as the guide be considered improper procedure?

Here is an exemplary approach to add something tangible to this question. It has an off-airport procedure turn with a requirement to remain within 10NM.

Answer 1

Using DME only is perfectly acceptable the FAA does not actually specify how exactly to execute the procedure turn but where and at what altitude. This is covered in the AIM:

5-4-9 Procedure Turn and Hold−in−lieu of Procedure Turn. A procedure turn is the maneuver prescribed when it is necessary to reverse direction to establish the aircraft inbound on an intermediate or final approach course. The procedure turn or hold−in−lieu−of−PT is a required maneuver when it is depicted on the approach chart, unless cleared byATC for a straight−in approach. Additionally, the procedure turn or hold−in−lieu−of−PT is not permitted when the symbol “No PT” is depicted on the initial segment being used, when a RADAR VECTOR to the final approach course is provided, or when conducting a timed approach from a holding fix. The altitude prescribed for the procedure turn is a minimum altitude until the aircraft is established on the inbound course. The maneuver must be completed within the distance specified in the profile view. For a hold−in−lieu−of−PT, the holding pattern direction must be flown as depicted and the specified leg length/timing must not be exceeded.

The guidance is pretty straight forward that you need to be at the prescribed altitude and within the "remain within" distance but the type and execution of the maneuver is largely up to the PIC as they go on to elaborate.

On U.S. Government charts, a barbed arrow indicates the maneuvering side of the outbound course on which the procedure turn is made.Headings are provided for course reversal using the 45 degree type procedure turn. However, the point at which the turn may be commenced and the type and rate of turn is left to the discretion of the pilot (limited by the charted remain within xx NM distance). Some of the options are the 45 degree procedure turn, the racetrack pattern, the teardrop procedure turn, or the 80 degree, 260 degree course reversal. Racetrack entries should be conducted on the maneuvering side where the majority of protected airspace resides. If an entry places the pilot on the non−maneuvering side of the PT, correction to intercept the outbound course ensures remaining within protected airspace. Some procedure turns are specified by procedural track.These turns must be flown exactly as depicted

The standard 1 minute timing is a convenient way to execute the maneuver for light aircraft since 1 minute at approach speed is usually ~1.5 miles (assuming a 90 Kt maneuver/approach speed) and will often keep you in the protected area.

Depending on how you read the regulation in reality a pilot may only use distance, although you may use time as an estimate and helper to execute the maneuver.