Take an imaginary gradient from the end of the runway rising at 6% along the path of the SID. If the departure requires a minimum % gradient (for example 6%) it means the aircraft should always be above that notional 6% slope.
At initial rotation the aircraft will be climbing at significantly more than 6%, with a high VS and low ground speed which will give a significant angle of climb, it will therefore be well above the slope it is required to be above by the time you reach acceleration altitude. You then speed up, clean up and carry on.
This all assumes all engines operating. In the event of a loss of the critical engine, then the requirement to achieve the 6% is no longer there. Often the 6% is for noise or airspace reasons, and not always for obstacle reasons. If however, there is an obstacle within the climb out, and if single engine the aircraft can not clear it, that is when you will have an emergency turn procedure on the departure. Otherwise, you follow the company standard engine fail procedures.
Generally SIDs are written to be comfortably achievable with commercial aircraft with no major concern, and if there is a challenging SID then usually additional notes, either on the plates or in company ops manuals will draw attention to it.
Hope that helps
You may want to amend your post here. On your imaginary 6% gradient the reason for that may be airspace or terrain. A noise abatement requirement is not an SID matter it is a noise abatement requirement that is separate to a SID. Your comment is potentially misleading, and not in a good way. Whether an operator provides a EOSID DP is entirely up to the operator, and the requirements of the regulator, which may differ in some serious ways to any assumptions of goodness, and to disregard a gradient requirement without comprehension is risky.
You may want to rephrase what you have said here... A SID may require gradients for various reasons, which may include airspace, AND TERRAIN CLEARANCE. You cannot assume that is does not require a gradient for an obstacle without the analysis which may come from an EO SID procedure... Some operators will not necessarily have EOSID's protection from obstacles may just arise from application of an obstacle/gradient related weight/temperature restriction.
Application of Takeoff performance usually (but not always..) assumes a straight out flight path for the second segment, whereas the SID may require other turns. The regulatory system that you are udner will determine exactly what is necessary, beyond the basics of the certification.
For the airline operators, that is a matter for your performance group, and they are usually open to a coffee and a discussion to ascertain exactly what you are required by your regulator to achieve. (I am not being obtuse, the requirement between states varies in subtle and occasionally surprising ways, particularly in relation to OEI). If you are a corporate operator, using a 3rd party performance analysis system, be aware that often that will indicate an obstacle that does not exist in reality. The obstacle data source occasionally throws up oddities, like an obstacle that is indicated in the middle of a major runway, a low level gradient requirement at another airport which has around 3NM of nothing from the DER. Another departure gives an obstacle for a departure over the ocean, with nothing higher than a gopher nearby. A quick confirmation of an issue can be done by looking at a runway cutback for such oddities, and that will show that the performance does or does not really consider the obstacle as indicated. When all else fails apply the obstacle constrained performance, but you may have the ability to turn that off, if your procedures permit and you have confirmed appropriately that the requirements of your regulator are being met. A pointer to an issue there is whether the departure procedure on the SID or otherwise has a gradient requirement. If it doesn't, then, consider what that is saying about obstacle analysis for the OEI case that the performance system is throwing up. A final oddity may be where the standard takeoff limit weights show an obstacle limit weight, and an OEI SID applied to the takeoff gives the same limit weight, that would suggest some thought is worthwhile.
The basic "Jeppesen SID" gradient is covered in the manual; (DOC 8168 excerpt) Jeppesen, ATC-202: Departure Procedures:
"A departure procedure will be established for each runway where instrument departures are expected to be used and will define a departure procedure for the various categories of aircraft based on ALL-ENGINE 'procedure design gradient' (PDG) of 3.3% or an increased PDG if required to achieve minimum obstacle clearance.
NOTE: Development of contingency procedures is the responsibility of the operator. Unless otherwise promulgated, a PDG of 3.3% is ASSUMED." but essentially provides for 200'/nm from the DER, which has an 48'/nm increase in clearance, and a slope of 152'/nm underlying (OCS or OIS, dependent on the rules in force, 3 different flavors under FAA..) the distance that is analysed also depends on the flavor of the rules, it may be 10nm, or under the diverse design may be out to 25 or 46nm, and giving a final clearance of 1000' or 2000'... or under the latest rendition of TERPS, the OCS will start a 0' at the DER... instead of 35'... (or 16'... for PANSOPS commencement of the OIS 2 2.5%). Jeppesen includes both TERPS and PANSOPS procedures....
Lateral splays alter as well dependent on your regulatory guidelines, which is great, so much for ICAO Annex. Terrain clearance in VMC can sometimes be applied, dependent on your regulator guidelines, such as FAA AC120-91... or for dunnundas, refer to CAO 20.7.1B or CAP235(0), and CAP235 4(0) For Canadians, its on your website that appears to have been designed by someone intent on ransomware. For Euros, EU OPS Annexes: Air Operations - OPS’ CAT.POL.A.210 Take-off obstacle clearance. For former EUROFYLZ, Post self immolation/ BREXIT, UKCAA CAP 778 Policy and Guidance for the Design and Operation of Departure Procedures in UK Airspace for normal procedure design, pretty silent on OEI, other than CAP 745 which tells ATC you may be doing odd stuff. Antibodeans (land of the long slow vowel) do well with Part 121.211 which is pretty comprehensive yet simple. (Good in a land of 63 million sheep wuth only 3 million wuth a vote. As Piggy said, RIP, every kiwi that escapes to Bondi increases the IQ of both countries. Love or hate him, he was a character, Sir Piggy).
(minimum clearances will alter in a turn, going from 35' to 50', for turns over 15 degrees of heading change until the turn is complete.... An OEI procedure with a required bank in excess of 15 degrees will have considerable penalties to it, as it should and will almost always have speed limitations as well. EU use 20 and also banks exceeding 30... interesting stuff... if you are an insomniac)
Anyone interested in the design needs to go to source, there are differences, and sometimes they are not trivial:
TERPS: FAA ORDER 8260.3D1 (is current as of AUG 2019)
https://www.faa.gov/documentLibrary/media/Order/FAA_Order_8260.3D1.pdf
Your Regulators AIP, ATC DEPARTURE PROCEDURES
FAR-AIM page 331, 5-2-9(e)
FAA INSTRUMENT PROCEDURES HANDBOOK FAA-H-8083-16B_Chapter_1.pdf pages 1-15 to 1-20
PANSOPS ICAO DOC 8168 VOL 1, and VOL 2
search for ICAO doc8168.pdf
To highlight why it is worthwhile getting the issue sorted in your mind read the following. For common sense, the AC120-91 and (remarkably) CASA's CAP 235 4(0), however the FAA suggests slightly more relief in design. Both are good basis for OEI procedures, but then your team may be doing something completely different, it's up to the regulator.
N 8900.487
SUBJ: IFR Departure Procedure Climb Gradient Compliance—Performance Planning
4. Background. FAA Order 8900.1, Volume 4, Chapter 3, Section 5, Safety Assurance System: Selected Practices, Paragraph 4-599, Deviation for Obstacle Clearance Data for Certain Turbojet Airplanes in Part 135 Operations, previously implied to inspectors that it was an acceptable practice to use OEI takeoff performance data for compliance with the Terminal Instrument Procedures (TERPS) climb gradient requirements published on a Standard Instrument Departure (SID), Diverse Vector Area (DVA), Obstacle Departure Procedure (ODP), and Missed Approach Procedures (MAP). This method is no longer acceptable because TERPS procedures assume normal all-engines-operating (AEO) climb performance of the airplane and currently do not consider low close-in obstacles when calculating the climb gradient requirements for the procedure. This matter is further complicated, as manufacturers are not required by the FAA to furnish AEO performance data for takeoff.
a. In an effort to meet the AEO takeoff performance requirements for these departure procedures, some inspectors have allowed or expected the use of OEI takeoff performance data as an accepted means of complying with the TERPS climb gradient. Also, with the absence of this manufacturer data, some inspectors have incorrectly considered OEI data to be the best available to meet the climb gradient requirements published on a SID, DVA, ODP, or MAP. Consequently, the incorrect use of OEI data has been mistakenly included in some operating procedures and training programs as an acceptable means of meeting IFR departure procedure requirements. This notice informs inspectors that such practices may neither ensure an aircraft will clear obstacles in every case (e.g., low, close-in obstacles), nor meet the necessary obstacle clearance altitude along the departure routing at the required geographic location.
b. POIs and TCPMs requiring the use of OEI procedures in these instances may be putting their pilots and operators at an unfair competitive disadvantage, compared to the POIs and/or TCPMs who understand that the application of OEI procedures in such cases is beyond the designed purpose of these data and procedures.
5. Guidance. The Safety Standards Flight Technologies and Procedures Division, in cooperation with the Office of Air Carrier Safety Assurance, the Office of General Aviation Safety Assurance, and the Aircraft Certification Service (AIR) Airplane and Flight Crew Interface Section, developed this notice. This notice announces the following changes to Order 8900.1 Volume 4, Chapter 3, Section 5: • Removal of superseded inspector guidance regarding the use of OEI takeoff data from Subparagraph 4-599C, Method of Granting the Deviation. • Addition of Paragraph 4-603, Compliance with IFR Departure and Missed Approach Climb Gradient Requirement; Paragraph 4-604, Use of OEI Special Departure Procedures; and Figure 4-40, Example IFR Climb Gradient and Climb Gradient Surface (Plane).
6. Action. POIs and TCPMs should review the updated guidance and review their operator’s or training center’s procedures and training program(s) to ensure they comply with the intent of this updated guidance.
a. Point of Emphasis for Operators. Inspectors and training centers should convey to operators that there is no FAA expectation or requirement to use OEI takeoff performance data to meet SID, DVA, ODP or MAP climb gradient requirements. Additionally, POIs and TCPMs should communicate that IFR departure procedures filed or assigned by air traffic control (ATC) are based on normal airplane operation and that OEI takeoff performance data should not be used for this purpose.
b. FAA Performance Planning Training Videos. The FAA has produced four training videos illustrating the proper application of aircraft departure and approach performance requirements, as well as other relevant performance topics. It is recommended that they be included as a part of approved ground training courses for pilots, dispatchers, and flight followers and/or planners of transport category airplanes. These videos may be viewed and/or downloaded at: https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afx/afs/af s400/afs410/obstacle/.
from CAP 235 4(0)
Regulations and References
• Civil Aviation Regulations 1988, Reg 235, Takeoff and Landing of Aircraft etc.
• Civil Aviation Order Part 20, Section 20.7.1B, Issue 5, Aeroplane Weight and Performance Limitations — Specified Aeroplanes Above 5700 kg — All Operations (Turbine and Piston and Engined)
• Civil Aviation Order Part 40, Section 40.2.1, Issue 4 Instrument Ratings.
• Getting to Grips with aircraft Performance, Airbus Publication
• Boeing Performance Training - Operations Course notes
• Boeing Jet Transport Methods, Document D61420, Seventh Edition dated May 1989
• Boeing FMS RNAV Workshop February 9,2000
• Code of Federal Regulations Title 14, Aeronautics and Space Part 25—Airworthiness Standards – Transport Category Airplanes.
• Code of Federal Regulations Title 14, Aeronautics and Space Part 77—Objects Affecting Navigable Airspace.
• Code of Federal Regulations Title 14, Aeronautics and Space Part 121—Operating Requirements, Domestic, Flag, and supplemental Operations.
• Boeing Document D6-39067-3 RNP Capability of FMC equipped 737, Generation 3 • Joint Aviation Requirements for Large Aeroplanes JAR-25
• ICAO Procedures for Air Navigation Services, DOC 8 168 Volume II, 4th Edition, Construction of Visual and instrument Flight Procedures. ( ...add VOL I as well, 5th edition, its a riveting read...)
• FAA Order 8260.3, United States Standard for Terminal Instrument Procedures (TERPS), current edition.
• FAA Order 8260. 48 Area Navigation (RNAV) Approach Construction Criteria
• FAA Order 8260.44A Civil Utilisation of Area Navigation (RNAV) Departure Procedures
• FAA Order 8260.40B Flight Management System (FMS) Instrument Procedures Development
• FAA Advisory Circular 120- OBS-11, Airport Obstacle Analysis, Draft Copy Issue
• RTCA DO-236A, Minimum Aviation System Performance Standards: Required Navigation Performance for Area Navigation, dated September 13,2000
• RTCA DO-201A Standards for Aeronautical Information, dated April 19, 2000
• ARINC Specification 424-17 Navigation System Data Base, published August 31, 2004
• Collins FMS Newsletter Business and Regional Systems July 1998 Volume 1, Issue 2
• FAA Notice N8400.80 Special Instrument approach and Engine Out Missed approach Procedures.
Following is from Gribble, it is competent and on topic. It is available on line, and was originally presented at Business Aviation Safety Seminar ● FSF and NBAA ● Montreal, Quebec, Canada ● April 2013
Departure End of Runway
The starting point in PANS-Ops and TERPS is at the departure end of runway (DER). This is the same term but is defined significantly differently. In PANS-Ops, DER can be the last portion of the runway suitable for takeoff or, if a clearway is used, the DER is “moved” to the end of the clearway and the highest elevation of the runway or clearway is used. TERPS specifically defines DER as the “end of the runway available for ground run of an aircraft.” The height used may be the height of the DER or as high as 35ft above it. The difference is based upon what the procedure designer needed. To make it more confusing, later changes in TERPS start terrain/obstacle evaluations at the more restrictive 0ft DER.
Required Climb Gradients
At the DER, PANS-Ops will add 5m/16ft and begin an upward slope of 2.5% to create an obstacle identification surface (OIS). Add to this .8% to ensure a minimum obstacle clearance (MOC). This will result in a 3.3% standard procedure design gradient (PDG). This gradient is used until the next phase of flight minimum obstacle clearance is met. Operationally, pilots know this as the MEA, MOCA, Grid MORA or minimum holding altitude. (#_edn1)
TERPS uses an obstacle climb surface (OCS) for this same purpose. OCS slopes upward at 152’/NM or 40:1 ratio. On top of this surface is added the required obstacle clearance (ROC). ROC slope is 48’/NM. Add the OCS to ROC and this becomes the familiar 200ft/NM standard. ROC increases along this slope until the next phase of flight minimum obstacle clearance is met. Just like in PANS-Ops, pilots know this as the MEA, MOCA, Grid MORA or minimum holding altitude. [ii] (#_edn2)
In both PANS-Ops and TERPS the net takeoff flight path clears all obstacles by a vertical distance of at least 35ft. Commercial operators have an additional horizontal requirement of 200ft laterally inside the airfield boundary and 300ft laterally outside the airfield boundary. TERPS/PANS-Ops does not define a requirement; operational regulations found in inside 14 CFR Part 121/135 does this. In a similar method, ICAO Annex 6 and EU-Ops defines lateral obstacle separation as 90m/295ft plus .125 times the distance from the DER.[iii] (#_edn3)
Departures, Horizontally Speaking
Both PANS-Ops and TERPS begin the horizontal evaluation of obstacles at the DER as described above. The initial width is 150M/500ft on either side of the runway centerline and splays 15° outward from both sides. This space on the departure is defined in PANS-Ops as “Area 1” and it extends 3.5Km/1.9NM. The length of this splay in TERPS is normally 2 NM but may be longer or shorter for early turns, a climb gradient required to a particular altitude/height, or a combination of both. TERPS labels this the initial climb area (ICA). [iv] (#_edn4)
What if a Straight-Out Departure Won’t Work?
Procedure designers have only a few options to compensate for local conditions and create a safe departure climb/path. The solutions fall into the broad categories of:
· Climb faster over the problem obstacle, [i]and/or
· Turn away from the problem obstacle, and/or
· Keep the problem insight and tell the pilot to “see and avoid” it, and/or
· Climb IMC in an area away from the problem and tell the pilot where this area is.
To climb faster, TERPS may require pilots to use a shorter ground run and earlier lift-off point on the runway via a displaced threshold and reduced takeoff run available (TORA) distances. A higher than standard climb gradient (>3.3%/200’ per NM) may also be required. TERPS will use only one such climb gradient all the way to an MEA. PANS-Ops will require this increase until MOC, then reduced to the standard climb gradient until at a published MEA.[v] (#_edn5)
To “see and avoid,” TERPS uses a climb in VMC conditions and conspicuous obstacle markings/lighting before allowing IMC entry. A “visual climb over airport” procedure will specify a minimum altitude and/or routing to cross over the airport or fix. Procedure designers use a standard 40:1 climb gradient for obstacle identification and ROC.[vi] (#_edn6) Greater than standard climb gradients may be directed in a particular sector or departures restricted to VMC conditions until minimum obstacle clearance is met.
PANS-Ops uses a procedure known as an omni-directional departure. This includes “Area 1” we previously discussed and adds “Area 2” and “Area 3.” Area 2 begins at the end of Area 1 and splays outward at 30º. Area 2 ends at the point from which a pilot may turn greater than 15º in any direction and not impact terrain or obstacles using the standard climb gradient of 3.3%. To define the required obstacle identification surface (OIS) for Area 3, a circle around the airport is drawn. The distance of this circle is the distance from 600m/1970ft from the approach end of the departure runway until minimum obstacle clearance is met using 3.3% climb gradient. [vii] (#_edn7)
When the Unexpected Is Happening
TERPS and PANS-Ops are for normal operations with all engines functioning, maintaining both the ground track and the required climb gradient until MEA. The “guarantee” of terrain and obstacle separation is only good while on the departure’s track and complying with the departure’s climb requirements. Abnormal circumstances are not accounted for. To illustrate the problem, assume a two-engine jet transport, engine failure on the runway and climbing up to 1,500AFL. The best climb gradient this aircraft is certified to perform is a NET 1.6%. Compare this to the standard climb gradient of 200’/NM or 3.3%.
The operational pilot must also consider the effects of:
Ø The pre-/post-1998 screen height differences 15ft or 35ft?
Ø Variable DER start positions for obstacle evaluation
Ø Procedure designer’s latitude in requiring more restrictive climb and maneuvering
Ø Aircraft certification standards only to 1,500AFL and not the operating MSA
It is easy to understand the need for pilots and operators to develop their own contingency procedures. This is universally applied inside TERPS and PANS-Ops.[viii] (#_edn8)
A Word About Minimum Safe and Minimum Sector Altitude Definitions
PANS-Ops will define MSA as a minimum SECTOR altitude. TERPS will define the same MSA as a minimum SAFE/SECTOR altitude. Both criteria define this as the lowest altitude that ensures at least 300m/1000ft of terrain and obstacle separation within 25NM from the NAVAID or waypoint defined. Interestingly, the FAA’s Aeronautical Information Manual directs that the MSA is for “emergency only” use and does not “guarantee” NAVAID reception. PANS-Ops and EU-Ops do not specify “emergency only” usage and make no mention of NAVAID reception.[ix] (#_edn9)
[i] (#_ednref1) PANS-Ops Volume 2, Part 1, Section 3, Chapter 2, “Design Principles”
FAA’s Instrument Procedures Handbook, FAA-H-8261-1A, Chapter 2, Page 2-12, “Design Criteria”
[ii] (#_ednref2) TERPS Volume 4, Chapter 1, “General Criteria”
[iii] (#_ednref3) 14 CFR 121.189, 135.379, EU-Ops 1.495
ICAO Annex 6, Part 1, Attachment C, Para. 5, “Take-off Obstacle Clearance Limitations”
[iv] (#_ednref4) TERPS Volume 4, Chapter 1, Paragraph 1.6, “Initial Climb Area”
[v] (#_ednref5) PANS-Ops Volume 2, Part 1, Section 3, Chapter 2, Para. 2.7, “Procedure Design Gradient”
TERPS Volume 4, Chapter 1, Paragraph 1.4.4 “Multiple Climb Gradient Application”
[vi] (#_ednref6) PANS-Ops Volume 2, Part 1, Section 3, Chapter 4, “Omnidirectional Departures”
TERPS Volume 4, Chapter 2, “Diverse Departures”
[vii] (#_ednref7) PANS-Ops Volume 2, Part 1, Section 3, Chapter 4, “Omnidirectional Departures”
TERPS Volume 4, Chapter 2, “Diverse Departures”
[viii] (#_ednref8) Runway lift-off to Landing Gear retracted is Segment#1; Landing Gear retracted to Flaps
retracted is Segment #2 and from Flaps retracted to no lower than 1500’AGL is Segment#3.
For any two-engine jet transport aircraft, the first segment has a minimum climb gradient of just “Positive Climb”.03% The screen height at DER is 35ft. Later certification (post 1998) criteria mandate a wet runway certification and use a 15ft screen height vice 35ft.
The second segment GROSS climb gradient for certification must be 2.4% for a two-engine aircraft. During this segment the NET flight path must clear any obstacle by at least 35ft. The minimum speed of V2 to a height of no lower than 400 feet above the takeoff surface or at a height that may be necessary to achieve obstacle clearance is mandated. The required GROSS gradients are further reduced to achieve this NET gradient. This reduction from the gross is 0.8% for a two-engine aircraft. This will result in the familiar 1.6% two-engine second segment NET climb gradient. Third segment, the aircraft has reached the acceleration altitude and will climb to no lower than 1500AGL. It must have a gradient climb equivalent of 1.2% for twin-engine aircraft, 1.4% for three engine aircraft and 1.5% for four engine aircraft.
[ix] (#_ednref9) TERPS Volume 1, Chapter 2, Paragraph 221, “Minimum Safe/Sector Altitudes”
ICAO Annex 4, Chapter 1, Appendix 2 “Minimum Sector Altitude”
Aeronautical Information Manual, Paragraph 5-4-5c “Minimum Safe/Sector Altitude”