climb gradient greater than 200 ft/NM, an increase in the  standard takeoff minimums to allow the aircraft to “see and  avoid” the obstacles, a standard climb of 200 ft/NM with a  specified reduced takeoff length, or a combination of these  options and a specific departure route.  separation between the obstacle clearance surface (OCS)  and the required climb gradient of 200 ft/NM. The ROC  value is zero at the DER elevation and increases along the  departure route until the ROC value appropriate for en route  flight is achieved. The appropriate ROC value for en route  operations is typically achieved about 25 NM for 1,000 feet  of ROC in non-mountainous areas, and 46 NM for 2,000 feet  of ROC in mountainous areas.  The obstacle environment may require a climb gradient  greater than 200 ft/NM. In these cases, the ROC provided  above obstacles is equivalent to 24 percent of the  published climb gradient. The required climb gradient,  for obstacle purposes on ODPs and SIDs, is obtained by  using the formulas:  If taking off from a runway using a diverse departure  (a runway without a published ODP), beyond these  distances the pilot is responsible for obstacle clearance if  not operating on a published route, and if below the MEA  or MOCA of a published route, or below an ATC-assigned  altitude. [Figure 1-15]  Recent changes in TERPS criteria make the OCS lower and  more restrictive. [Figure 1-16] However, there are many  departures today that were evaluated under the old criteria  that allowed some obstacle surfaces to be as high as 35 feet  at the DER. [Figure 1-14] Since there is no way for the pilot  to determine whether the departure was evaluated using  the previous or current criteria, and until all departures  have been evaluated using the current criteria, pilots need  to be very familiar with the departure environment and  associated obstacles, especially if crossing the DER at less  than 35 feet.  All departure procedures are initially assessed for obstacle  clearance based on a 40:1 Obstacle Clearance Surface (OCS).  If no obstacles penetrate this 40:1 OCS, the standard 200  ft/NM climb gradient provides a minimum of 48 ft/NM of  clearance above objects that do not penetrate the slope.  The departure design must also include the acquisition  of positive course guidance (PCG), typically within 5 to 10  NM of the DER for straight departures. Even when aircraft  performance greatly exceeds the minimum climb gradient,  the published departure routing must always be flown.  These formulas are published in FAA Order 8260.3 for  calculating the required climb gradient to clear obstacles.  The following formula is used for calculating SID climb  gradients for other than obstacles (i.e., ATC requirements):  Airports publish the declared distances in the A/FD section  of the CS. These include takeoff runway available (TORA),  takeoff distance available (TODA), accelerate-stop distance  available (ASDA), and landing distance available (LDA). These  distances are calculated by adding to the full length of paved  runway any applicable clearway or stop-way and subtracting  from that sum the sections of the runway unsuitable for  satisfying the required takeoff run, takeoff, accelerate/stop,  or landing distance as shown in Figure 1-16.  Optimally, the 40 to 1 slope would work for every departure  design; however, due to terrain and manmade obstacles,  it is often necessary to use alternative requirements to  accomplish a safe, obstacle-free departure design. In  such cases, the design of the departure may incorporate a  The published climb gradient, obstacle or otherwise, is  1-17  Example:  Note: The climb gradient must be equal to or greater than  the gradient required for obstacles along the route of flight.  If a departure route is specified, it must be flown in  conjunction with the other options.  3000 – 1221  = 355.8 round to 356 ft/NM 5  CG = A – E  D  2049 – 1221  (48 × 3.1 + 2049) – 1221  = 351.44  = 315.10 0.76 × 3.1  3.1  Examples: O = obstacle mean sea level (MSL) elevation E = climb gradient starting MSL elevation D = distance (NM) from DER to the obstacle A = “climb to” altitude  E = climb gradient starting MSL elevation  D = distance (NM) from the beginning of the climb  Round to 352 ft/NM  *Military only  Round to 316 ft/NM  Standard Formula  DoD Option*  CG = (48D + O) – E D  CG = O – E  0.76 D 