CHAPTER 6 - ASSAULT LANDING ZONE OPERATIONS Flashcards
(126 cards)
What is considered a “standard operating strip”?
5,000 ft x 60 ft
Define an ALZ
natural, semi-prepared, or prefabricated strip with surface, slope, dimensions, load-bearing capacity, and clearance from obstructions
sufficient to allow suitably-trained crews to takeoff/land in good weather conditions
What AF pub can be used to find ALZ info?
AFI 13-217, Drop Zone and Landing Zone Operations
What 3 categories are airfields generally divided into?
- high-strength
- marginal strength
- substandard
Define High-Strength Airfield
paved runways either Rigid (concrete) or Flexible (asphalt) with a subgrade code indicating strength of soil bearing the runway environment
Define Marginal Strength Airfield
temporary airfields with minimally surfaced or unsurfaced runways such as dirt, grass, gravel, coral, etc
surface/soil strength evaluated in terms of California Bearing Ratio
What is CBR?
California Bearing Ratio
lower numerical values indicate lower subgrade strength - surfacing material is considered to be ineffective and only the subgrade soil is considered in defining the airfield strength
What is the minimum soil strength required for operation on marginal strength airfields?
When should particular consideration be given to operations? (what value?)
CBR value of 3
CBR of 6 or less
What can adverse soil characteristics result in?
poor braking, unpredictable rutting or other surface deterioration, airframe damage from thrown dirt/gravel, engine FOD
What constitutes a “pass”?
1 landing plus 1 takeoff
The number of passes is predicated on what?
aircraft weight and CBR
based on recommended tire pressures corresponding to 39% tire deflection for marginal strength airfields
To prevent excessive tire damage what should you do?
do not exceed 39% tire deflection
To minimize a/c and engine maintenance on marginal strength/substandard what are some things you can do?
- inflate/deflate MLG tires to recommended psi
- empty external fuel tanks
- do not exceed 10 kts while taxiing
- minimize braking if porpoising occurs
- minimize nose gear loads by using elevator during landing rollout and takeoff / load a/c to mid or aft CG
- minimize use of reverse
- shut off FS and cargo AC to prevent clogging of heat exchanger unit
- limit gross weight to 164K
Define Substandard Airfields
may be either paved or unpaved and have unusually rough, undulating, pitted, or rutted runways
visible ruts
most likely not considered for normal/routine operations
Operational feasibility on unsurfaced airfields depend on what?
soil type, soil moisture content, and operational frequency
What do Ground Flotation charts do?
permit matching the loads that the aircraft imposes on an airfield to the strength capability of the airfield
Ground flotation characteristics are correlated for the following 5 methods of evaluating runway strength:
- Footprint Loading (pressure) - same as tire inflation pressure
- Unit Construction Index (UCI) - determine characteristics of comparative a/c, seldom used
- Equivalent Single-Wheel Load (ESWL) - determined from geometry of multiple wheeled landing gears, number and size of tires, a/c weight. Where data are given in terms of ESWL, UCI & LCN values can be calculated
- Load Classification Number (LCN) - when this is used (primarily outside US), data shown on ground flotation charts can be used to estimate the capability of a/c to operate from given airfield
- CBR - represent required surface hardness for operation of a/c in terms of weight and number of passes
Which fields can be evaluated in terms of CBR?
only unpaved surfaces
To compute minimum runway required
unless otherwise specified, compute landing distance or ground roll with what?
4 engines in reverse and full brakes
Minimum Runway Required
land with training crew
3,000 ft
or
ground roll + 1000 ft
whichever is greater
Minimum Runway Required
takeoff with training crew
3,000 ft
or
ground run + 1,000 ft
or
AMFLMETO + 500 ft
whichever is greater
Minimum Runway Required
land with sustainment training/operational crew
Ground roll + 500 ft w/ 4 engine reverse and full brakes
No wind, 150% tailwinds
Minimum Runway Required
takeoff with sustainment training/operational crew
Ground run + 500 ft
or
AMFLEMTO, whichever is greater
No wind, 150% tailwinds
What don’t we use MFLMETO?
does not provide adequate safety margins for engine loss below Vmca
takeoffs with field length between AMFLMETO and MFLEMETO require approval by the appropriate authority