INTERMEDIATE FLIGHT PREPARATION WORKBOOK
Penetration vs. Enroute Descent
Jet aircraft approaching the terminal phase from the high altitude structure have a choice of a
high altitude penetration or an enroute descent. ATC will often ask what type of approach is
desired approximately 200 miles from your destination. If you wish to execute the entire
published high altitude approach, you need to request the penetration. If ATC does not make this
request, they will assume you desire an enroute descent. Be wary of altitude assignments below
the IAF altitude. If you want a low altitude approach, or desire vectors to an ILS, a GCA or
TACAN final, you should request the enroute descent. The aircrew may refuse an enroute
descent in favor of a penetration approach.
The approach phase requires constant vigilance. It is very easy to misdirect your focus during
this phase of flight. There are many checklists and briefs to perform, and the airspace is
significantly more crowded.
The Descent Checklist includes numerous items that must be accomplished early so the crew is
ready for the approach. Weather information for the destination airfield should be obtained at
least 100-150 NM prior to the destination by listening to ATIS or calling METRO. In either
case, monitor center while up the different frequency. If the weather on ATIS is questionable,
METRO should be contacted for further information.
The normal method of setting up for TACAN approach is to proceed directly to the IAF and
commence the approach. However, it may be necessary to enter holding. Recommended holding
speed for the T-1A aircraft is 180 KIAS. The aircraft should be slowed 3 minutes prior to
entering holding. The 3 methods of entering are:
The type of entry is dependent upon the aircraft's heading when crossing the holding fix and can
be determined by using the entry diagram at the top of the high altitude approach plate or
standard entry procedures.
T1-A FLIGHT PROFILES 2-15