2.1.2 Helicopters flying Copter SIAPs may use the published minima, with no reductions allowed. The maximum airspeed is 90 KIAS on any segment of the approach or missed approach.
2.1.3 Helicopters flying GPS Copter SIAPs must limit airspeed to 90 KIAS or less when flying any segment of the procedure, except speeds must be limited to no more than 70 KIAS on the final and missed approach segments. Military GPS Copter SIAPs are limited to no more than 90 KIAS throughout the procedure. If annotated, holding may also be limited to no more than 70 KIAS. Use the published minima, no reductions allowed.
NOTE.
Obstruction clearance surfaces are based on the aircraft speed and have been designed on these approaches for 70 knots. If the helicopter is flown at higher speeds, it may fly outside of protected airspace. Some helicopters have a VMINI greater than 70 knots; therefore, they can not meet the 70 knot limitation to conduct this type of procedure. Some helicopter autopilots, when used in the “go.around” mode, are programmed with a VYI greater than 70 knots, therefore when using the autopilot “go.around” mode, they can not meet the 70 knot limitation to conduct this type of approach. It may be possible to use the autopilot for the missed approach in the other than the “go.around” mode and meet the 70 knot limitation to conduct this type of approach. When operating at speeds other than VYI or VY, performance data may not be available in the RFM to predict compliance with climb gradient requirements. Pilots may use observed performance in similar weight/altitude/temperature/speed conditions to evaluate the suitability of performance. Pilots are cautioned to monitor climb performance to ensure compliance with procedure requirements.
NOTE.
VMINI . Instrument flight mimum speed, utilized in complying with minimum limit speed requirements for instrument flight VYI . Instrument climb speed, utilized instead of VY for compliance with the climb requirements for instrument flight VY . Speed for best rate of climb
2.1.4 TBL ENR 6.1.1 summarizes these require-ments.

Federal Aviation Administration Twentieth Edition
TBL ENR 6.1.1
Helicopter Use of Standard Instrument Approach Procedures
Procedure  Helicopter Visibility Minima  Helicopter MDA/DA  Maximum Speed Limitations 
Conventional (non.Copter)  The greater of: one half the Category A visibility minima, 1/4 statute mile visibility, or 1200 RVR  As published for Category A  The helicopter may initiate the final approach segment at speeds up to the upper limit of the highest Approach Category authorized by the procedure, but must be slowed to no more than 90 KIAS at the MAP in order to apply the visibility reduction. 
Copter Procedure  As published  As published  90 KIAS when on a published route/track. 
GPS Copter Procedure  As published  As published  90 KIAS when on a published route or track, EXCEPT 70 KIAS when on the final approach or missed approach segment and, if annotated, in holding. Military procedures are limited to 90 KIAS for all segments. 

NOTE.
Several factors effect the ability of the pilot to acquire and maintain the visual references specified in 14 CFR Section 91.175(c), even in cases where the flight visibility may be at the minimum derived by TBL ENR 6.1.1. These factors include, but are not limited to:
1.
Cockpit cutoff angle (the angle at which the cockpit or other airframe structure limits downward visibility below the horizon).

2.
Combinations of high MDA/DH and low visibility minimum, such as a conventional nonprecision approach with a reduced helicopter visibility minima (per 14 CFR Section 97.3).

3.
Type, configuration, and intensity of approach and runway lighting systems.

4.
Type of obscuring phenomenon and/or windshield contamination.

2.1.5 Even with weather conditions reported at or above landing minima, some combinations of reduced cockpit cutoff angle, minimal approach/run-way lighting, and high MDA/DH coupled with a low visibility minima, the pilot may not be able to identify the required visual reference(s) during the approach, or those references may only be visible in a very small portion of the pilot’s available field of view. Even if identified by the pilot, these visual references may not support normal maneuvering and normal rates of descent to landing. The effect of such a combination may be exacerbated by other conditions such as rain on the windshield, or incomplete windshield defogging coverage.
2.1.6 Pilots are cautioned to be prepared to execute a missed approach even though weather conditions may be reported at or above landing minima.
NOTE.
See Section ENR 1.5, paragraph 27., Missed Approach, for additional information on missed approach procedures.
3. Helicopter Approach Procedures to VFR Heliports
　
中國航空網(wǎng) www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：美國航行情報匯編 AERONAUTICAL INFORMATION PUBLICATION AIP 3(68)