時間：2011-04-18 00:50來源：藍(lán)天飛行翻譯 作者：航空 點(diǎn)擊：次
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5.4.28 4. A teardrop procedure or penetration turn may be specified in some procedures for a required course reversal. The teardrop procedure consists of departure from an initial approach fix on an outbound course followed by a turn toward and intercepting the inbound course at or prior to the intermediate fix or point. Its purpose is to permit an aircraft to reverse direction and lose considerable altitude within reasonably limited airspace. Where no fix is available to mark the beginning of the intermediate segment, it shall be assumed to commence at a point 10 miles prior to the final approach fix. When the facility is located on the airport, an aircraft is considered to be on final approach upon completion of the penetration turn. However, the final approach segment begins on the final approach course 10 miles from the facility. Arrival Procedures 5. A holding pattern in lieu of procedure turn may be specified for course reversal in some procedures. In such cases, the holding pattern is established over an intermediate fix or a final approach fix. The holding pattern distance or time specified in the profile view must be observed. 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. Maximum holding airspeed limitations as set forth for all holding patterns apply. The holding pattern maneuver is completed when the aircraft is established on the inbound course after executing the appropriate entry. If cleared for the approach prior to returning to the holding fix, and the aircraft is at the prescribed altitude, additional circuits of the holding pattern are not necessary nor expected by ATC. If pilots elect to make additional circuits to lose excessive altitude or to become better established on course, it is their responsibility to so advise ATC upon receipt of their approach clearance. NOTE. Some approach charts have an arrival holding pattern depicted at the IAF using a “thin line” holding symbol. It is charted where holding is frequently required prior to starting the approach procedure so that detailed holding instructions are not required. The arrival holding pattern is not authorized unless assigned by Air Traffic Control. Holding at the same fix may also be depicted on the enroute chart. A hold.in.lieu of procedure turn is depicted by a “thick line” symbol, and is part of the instrument approach procedure as described in paragraph 5.4.9. (See U. S. Terminal Procedures booklets page G1 for both examples.)6. A procedure turn is not required when an approach can be made directly from a specified intermediate fix to the final approach fix. In such cases, the term “NoPT” is used with the appropriate course and altitude to denote that the procedure turn is not required. If a procedure turn is desired, and when cleared to do so by ATC, descent below the procedure turn altitude should not be made until the aircraft is established on the inbound course, since some NoPT altitudes may be lower than the procedure turn altitudes. b. Limitations on Procedure Turns. 1. In the case of a radar initial approach to a final approach fix or position, or a timed approach from a holding fix, or where the procedure specifies NoPT, no pilot may make a procedure turn unless, when final approach clearance is received, the pilot so advises AIM ATC and a clearance is received to execute a procedure turn. 2.When a teardrop procedure turn is depicted and a course reversal is required, this type turn must be executed. 3.When a holding pattern replaces a procedure turn, the holding pattern must be followed, except when RADAR VECTORING is provided or when NoPT is shown on the approach course. The recommended entry procedures will ensure the aircraft remains within the holding pattern’s protected airspace. As in the procedure turn, the descent from the minimum holding pattern altitude to the final approach fix altitude (when lower) may not commence until the aircraft is established on the inbound course. Where a holding pattern is established in.lieu.of a procedure turn, the maximum holding pattern airspeeds apply. REFERENCE. AIM, Holding, Paragraph 5.3.7j2. 4. The absence of the procedure turn barb in the plan view indicates that a procedure turn is not authorized for that procedure. 5.4.10. Timed Approaches from a Holding Fix a. TIMED APPROACHES may be conducted when the following conditions are met: 1.A control tower is in operation at the airport where the approaches are conducted. 2.Direct communications are maintained between the pilot and the center or approach controller until the pilot is instructed to contact the tower. 3.If more than one missed approach procedure is available, none require a course reversal. 4.If only one missed approach procedure is available, the following conditions are met: (a)Course reversal is not required; and, (b)Reported ceiling and visibility are equal to or greater than the highest prescribed circling minimums for the IAP. 5. When cleared for the approach, pilots shall not execute a procedure turn. (14 CFR Section 91.175.)Arrival Procedures 5.4.29 b. Although the controller will not specifically state that “timed approaches are in progress,” the assigning of a time to depart the final approach fix inbound (nonprecision approach) or the outer marker or fix used in lieu of the outer marker inbound (precision approach) is indicative that timed approach procedures are being utilized, or in lieu of holding, the controller may use radar vectors to the Final Approach Course to establish a mileage interval between aircraft that will insure the appropriate time sequence between the final approach fix/outer marker or fix used in lieu of the outer marker and the airport. c. Each pilot in an approach sequence will be given advance notice as to the time they should leave the holding point on approach to the airport. When a time to leave the holding point has been received, the pilot should adjust the flight path to leave the fix as closely as possible to the designated time. (See FIG 5.4.17.) |
