1. BRIDGES, TUNNELS AND UNDERPASSES
RECONNAISSANCE
BRIDGES, TUNNELS
AND UNDERPASSES
TC / FM 5-170

2. BRIDGE RECONNAISSANCE
Bridges are reconnoitered to determine type, condition, dimensions, bypass capability, and load carrying capability.
Tunnels and underpasses are reconnoitered to determine their dimensions and bypass capabilities

3. BRIDGE RECONNAISSANCE
           
Bypass easy. Use when the obstacle can be crossed in the immediate vicinity by a US 5-ton truck without work to improve the bypass.
Bypass difficult. Use when the obstacle can be crossed in the immediate vicinity, but some work to improve the bypass is necessary.
Bypass impossible. Use when the obstacle can be crossed only by repairing or constructing a feature or by detouring around the obstacle.
A bypass is considered easy when the obstacle can be crossed within the immediate vicinity (4 SM or 6.5 KM and 15 minutes) by a 5-ton vehicle without work to improve the bypass.
The bypass is considered difficult when the obstacle can be crossed within the immediate vicinity (4 SM or 6.5 KM) ; however, some work is necessary to prepare the bypass (ensure that the estimation of time, troops, and equipment necessary to prepare the bypass is included on the recon report).
The bypass is considered impossible when the obstacle can be crossed only by repairing the existing bridge or tunnel, building a new bridge or tunnel, or providing a detour that does not meet the Immediate Vicinity limitations.

4. BRIDGE RECONNAISSANCE
MILITARY LOAD CLASSIFICATION
A route’s MLC is a class number representing the safe load-carrying capacity and indicating the maximum vehicle class that can be accepted under normal conditions. Usually, the lowest bridge MLC (regardless of the vehicle type or conditions of traffic flow) determines the route’s MLC. If there is not a bridge on the route, the worst section of road will determine the route’s overall classification.
The entire network’s class is determined by the minimum load classification of a road or a bridge within the network.
The broad categories are:
Class 50 — average-traffic route.
Class 80 — heavy-traffic route.
Class 120 — very heavy-traffic route.

5. Table E-1. Reference list of common vehicles with MLCs
FM ( Appendix E )
Table E-1. Reference list of common vehicles with MLCs
Nomenclature
Name
Description
MLC Empty
MLC Loaded
MaxPro
MRAP - Cat I
Wheeled: Truck, 2 axle 18
MRAP - Cat II 21
Modular base petroleum laboratory (MBPL)
Modular base petroleum laboratory
Wheeled: semitrailer, axle 14
Mortar carrier (MC) (B)
Stryker - Mortar carrier vehicle (Version B)
Wheeled: Truck 4 axle
MK 48/17
Logistics Vehicle system, LVS, articulated drop side cargo truck 20 41 M1
Abrams with minefield clearing blade
Tracked: vehicle
(Estimated)
M1 towing
Abrams towing Abrams
Tracked: quadritracked
150+
M1 with mine roller
Abrams with mine roller ( raised) 88

6. RECONNAISSANCE
The principles of an air route reconnaissance are the same as for a route reconnaissance except that the areas of interest are different. Aviation forces moving along an air route are primarily concerned with the location of enemy forces, ease of navigation, suitability of landing sites and zones, and hazards to flight. Hazards to flight include suspected enemy AD locations, mountainous areas, wires, large bodies of water, open terrain, and other natural and man-made features.
URS Fort Rucker - Teaching those who “Fly above the best.”

7. NOTE:
In today’s Army, RECONNAISSANCE is everybody’s mission and is conducted before, during and after all operations.
QUESTIONS?