Minimum Altitudes

LOW-LEVEL AND TACTICAL FORMATION

CHAPTER ONE

day of the flight, your drift correction (DC) or MH can be placed just above the MC on your

map. MH is what will be flown in the aircraft.

Minimum Altitudes. Low-Level navigation is flown at an altitude of 500 to 1500 feet AGL.

Day VMC. Plan a minimum of 500 feet AGL using visual reference and the radio

altimeter. Modified Contour flight is defined as flight in reference to a base altitude

(500 feet AGL) above terrain with momentary deviations above and below the base

altitude for terrain depressions and obstructions to permit a smooth flight profile.

Night VMC. Prior to slowdown, fly each leg or segment of the route at an indicated

altitude of 1000 feet above the highest man-made obstacle or terrain feature and spot

elevation within 5 NMs of route centerline to include the aircraft turning radius over

each turnpoint. If the altitude for the next leg is higher than the current leg

altitude, the climb will be completed prior to the turnpoint. If the altitude for

the next leg is lower than the current leg, do not initiate descent until over the

turnpoint.

Minimum Safe Altitude (MSA). MSA is an initial VFR altitude which provides

terrain clearance while the aircrew analyzes situations that require interruption of

low-level operations (route disorientation and equipment malfunctions or when either

pilot must leave the seat during low-level operations, etc.), yet limits threat detection.

A MSA may be computed for each leg, route segment, or entire low-level route.

The MSA is calculated by adding 500 feet to the highest man-made obstacle or

terrain feature within 5 NMs of course centerline. Calculate an MSA for each leg of

the low-level route. Do not fly lower than calculated night altitude on night low-

levels until the drop zone is positively identified.

Emergency Safe Altitude (ESA). This altitude is calculated (and rounded to the

next highest 100 foot increment) to ensure terrain clearance in the event a crew must

abort an MTR when the weather is insufficient to continue the route, or an aircraft

malfunction requires termination of the low-level route. It provides 1000 feet of

clearance (2000 feet in mountainous terrain) from the highest obstacle within 22 NM

on either side of course for the entire low-level route. Under normal circumstances,

you exit the route under VFR conditions or on an IFR clearance. However, due to a

delayed pilot decision, an aircraft malfunction, becoming lost or disoriented, or

rapidly deteriorating weather, you may have to perform an emergency climb through

the weather to the computed ESA. You are expected to plan ahead and make timely

decisions concerning the need for route aborts. If the need arises, do not hesitate to

transition to instruments, roll wings level, and initiate a climb to this altitude. The

acceleration can give you a feeling of excessive pitchup; it is vital you crosscheck

your attitude indicator. Do not attempt to reenter the route once you initiate the

route abort. Proceed to your destination and analyze what happened and why.

LOW-LEVEL NAVIGATION 1-15