While viewing the following approach chart, which is an RNAV(RNP) CAT C Approach, there are several landing minima, stating a HEIGHT LOSS OF 50' AND 150', what does that specifically mean?
The approach above appears to be associated with the Antonio Marino Airport, Colombia, South America: (I don't know if it is current or proposed)
Descent below the published DA/H is not permitted due to obstacle clearance requirements. Therefore, a "height loss" (amount of altitude expected to be lost during a go-around [missed approach]) is added to the minimums to account for this.
The first minimum on the chart is 6240 ft. with a 50 ft height loss added and assumes a missed approach climb gradient of 5%. The second minimum is 6340 ft. with a 50 ft. height loss added and assumes a climb gradient of 4%.
The 50 ft. added for the height loss is based on the use of a "radio altimeter."
The third minimum on the chart is 6340 ft. with a 150 ft. height loss added and assumes a missed approach climb gradient of 5%. The other minimums, all with a 150 ft. height loss added, assume missed approach climb gradients as low as 2.5%.
The 150 ft. added for height loss is based on the use of a "pressure altimeter."
The chart below is from an advanced version of "Required Navigation Performance Authorization Required (RNP AR) Procedure Design Manual" ICAO Doc 9905-AN/471
NOTE: the added height loss for "radio altimeter" use (category C aircraft) shows 71 ft on the chart below. The published height loss on the OPs IAP plate shows 50 ft. I do not know why there is a difference unless the requirements are country localized or the ICAO document has been modified.