Narrative:

First officer flying. I was off frequency to get ATIS. While I was off; ATC gave us 'descend via the wlder 8.' I came back on frequency. First officer informed me of the clearance. He descended to cross spker intersection at FL230 and 280 knots. He made that restriction just fine. (Chart says to cross spker at FL230 or below and 280 KIAS.) however; the next restriction is at ltown intersection at 10;000 feet and 230 KIAS (we were landing south). The problem is that if you cross spker exactly at FL230 and 280 KIAS; it is physically impossible to make the ltown restriction. Spker to ltown is only 19 nautical miles. I realize the spker restriction is FL230 or below; but this is misleading. In my mind; no STAR should be designed to be impossible to satisfy--making one restriction; impossible to make the next. The STAR should be changed. Delete the FL230 (keep the 280 KIAS) at spker. We design STAR's to not only satisfy ATC airspace requirements; but also to provide fuel-efficient; safe; and quiet descents. This philosophy was first initiated in the 'profile descents' at denver in the late 70's and early 80's. A 'normal' profile to meet the ltown restriction would be to cross spker at about 15;000 feet (3:1 descent profile plus allowance to slow from 280 KIAS to 230 KIAS). This is quite a difference from the at-or-below FL230 published at spker. Even if memphis is landing north; FL230 to 16;000 feet (spker/ltown) is 7;000 feet to lose. A 3:1 profile would require 21 nautical miles; with only 19 nautical miles between the two fixes. Again; I understand the restriction at spker is FL230 or below. But; again; the published altitude and speed restrictions should allow for a reasonable descent profile.

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Original NASA ASRS Text

Title: Captain of a non FMC LR35 reports missing the crossing restriction at LTOWN; landing south with the First Officer flying; after making the restriction at SPKER; due to an excessive amount of altitude to lose by LTOWN.

Narrative: First Officer flying. I was off frequency to get ATIS. While I was off; ATC gave us 'descend via the WLDER 8.' I came back on frequency. First Officer informed me of the clearance. He descended to cross SPKER intersection at FL230 and 280 knots. He made that restriction just fine. (Chart says to cross SPKER at FL230 or below and 280 KIAS.) However; the next restriction is at LTOWN intersection at 10;000 feet and 230 KIAS (we were landing south). The problem is that if you cross SPKER exactly at FL230 and 280 KIAS; it is physically impossible to make the LTOWN restriction. SPKER to LTOWN is only 19 nautical miles. I realize the SPKER restriction is FL230 or below; but this is misleading. In my mind; no STAR should be designed to be impossible to satisfy--making one restriction; impossible to make the next. The STAR should be changed. Delete the FL230 (keep the 280 KIAS) at SPKER. We design STAR's to not only satisfy ATC airspace requirements; but also to provide fuel-efficient; safe; and quiet descents. This philosophy was first initiated in the 'profile descents' at Denver in the late 70's and early 80's. A 'normal' profile to meet the LTOWN restriction would be to cross SPKER at about 15;000 feet (3:1 descent profile plus allowance to slow from 280 KIAS to 230 KIAS). This is quite a difference from the at-or-below FL230 published at SPKER. Even if Memphis is landing north; FL230 to 16;000 feet (SPKER/LTOWN) is 7;000 feet to lose. A 3:1 profile would require 21 nautical miles; with only 19 nautical miles between the two fixes. Again; I understand the restriction at SPKER is FL230 or below. But; again; the published altitude and speed restrictions should allow for a reasonable descent profile.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.