Hel Performance

Helicopter PerformanceHelicopter Performance

Performance Class 1Performance Class 1

Jim LyonsJim Lyons

HEMS Seminar 15

Helicopter Performance Helicopter Performance –– Performance Class 1Performance Class 1

Content of PresentationContent of Presentation

• What is Performance Class 1

• Elements of a Category A Take-off Procedure (CS/FAR 29)

• PC1 Take-off Requirements

• PC1 En-Route Requirements

• PC1 Landing Requirements

• Category A Extensions

HEMS Seminar 16


OperationalOperational -- ClassificationClassification

Performance Class 1Performance Class 1 operations are those with performance such that, in the event of failure of the critical power unit, the helicopter is able to land within the rejected take-off distance available or safely continue the flight to an appropriate landing area, depending on when the failure occur.

HEMS Seminar 17


Category A Category A –– The DefinitionThe Definition

Category A with respect to rotorcraft, means a multi-engined rotorcraft designed with engine and system isolation features specified in CS–27 / CS–29 and capable of operations using take-off and landing data scheduled under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight or safe rejected take-off in the event of engine failure.

HEMS Seminar 18


Category A – The Application

• The provision of performance data must be supplemented by operating rules

• Clearly it is the operational regulationoperational regulation which indicates how an operation should be conducted

• JAR-OPS indicates not only when to operate within a certain Performance Class but also specifies the requirements

HEMS Seminar 19


What Does Category A Provide?

HEMS Seminar 20


Category A Category A –– What does it Provide?What does it Provide?

• Category A is a Certification Standard which:• Provides assurance of continued flight in the event of failure (engine

isolation, fire protection etc); or

• Ensures design assessment to reduce the probability of failure; or

• Provides improved crashworthiness

• Requires provision of performance data so that OEI obstacle clearance in take-off, climb, cruise and landing can be calculated.

• This Standard is built in to CS/FAR 29

• The provisions give a level of assurance that the helicopter can be operated for continuous periods over a hostile environment

HEMS Seminar 21


Category A – Graphical Summary

Redundancy

Fuel Separation

Fire Detection

Crash Protection

Fault Tolerance

Fire Suppression

Performance DataDesign Assessment

HEMS Seminar 22


Light Twin Category A (<3175 Kg)Light Twin Category A (<3175 Kg)

• FAR/CS 27 Category A:• Light twins certificated in accordance with FAR/CS 27 may be

certificated to Category A in compliance with Appendix C of FAR/CS 27.

• Appendix C calls up a number of requirements from FAR/CS 29, which provide a similar (but not equivalent) level of airworthiness and the provision of performance data.

• It should not be assumed that all light twins certificated in accordance with FAR/CS 27 have been certificated to Category A (even if performance data is provided or available).

• For older types (AS355, Bo105, A109) certificated before Appendix C of FAR/CS 27, there is a means of showing equivalence in JAR-OPS 3.

HEMS Seminar 23


What are the Elements of a Category A TakeWhat are the Elements of a Category A Take-- off Procedure (CS/FAR 29)?off Procedure (CS/FAR 29)?

HEMS Seminar 24


Category A TakeCategory A Take--off (FAR/CS 29)off (FAR/CS 29)

• AC29-2C describes Category A in the following terms:• Takeoff

• Rejected Takeoff

• Takeoff Path

• Continued Climbout Path

• This is difference terminology than that used in JAR-OPS 3

• These terms are descriptive whilst the JAR-OPS 3 ones are prescriptive

HEMS Seminar 25


Category A Takeoff (CS/FAR Terminology)

Reject takeoffTakeoff Path

Distance to Vy at 200 ft

200 ft

1st segment climb100ft/min at Vtoss

2nd segment climb150ft/min at Vy

Vtoss +ROC 35ft

Acceleration from Vtoss to Vy

TDP

1000 ft

Continued Climbout Path

HEMS Seminar 26


What are the What are the AdditionalAdditional Elements of a PC1 Elements of a PC1 Procedure?Procedure?

HEMS Seminar 27


Category A

Redundancy

Separation

Crash Protection

Fault Tolerance

Fire Detection Fire Suppression

Category A and PC1

Obstacle Clearance Performance Data

HEMS Seminar 28


TakeTake--off Requirements off Requirements –– PC1PC1

• Mass does not exceed the MTOM for the procedure being used• It is possible to land on the FATO following a engine failure at or before

the TDP (a statement about the quality of the surface)

• The ‘rejected take-off distance required’ (RTODRH) is less than the ‘rejected take-off distance available (RTODAH)’; and

• The take-off distance required (TODRH) is less than take-off distance available (TODAH); as an alternative the take-off distance required can exceed that available providing all obstacles can be cleared by a vertical margin of 35ft

•• All of this implies a All of this implies a formalityformality that is associated not only with the that is associated not only with the procedure but with the facilities at the siteprocedure but with the facilities at the site

HEMS Seminar 29


Obstacle Clearance – PC1

• The Category A procedures provide nonnon--adjustedadjusted profiles (they specify the minimum climb performance required by the procedure – i.e. take-off mass is established by using the WAT graph using the lowest standard)

• Only from the TakeTake--off Flight Pathoff Flight Path (which starts at the point where TakeTake--off Distance Requiredoff Distance Required is established) does account need to be taken of obstacles in the obstacle accountability area.

• Obstacle clearance is specified onlyonly in operational regulations (for both PC1 and PC2) and has to be considered for departure at any specific site.

HEMS Seminar 30


Provisions Given by Heliport (Annex 14)

Facilities Given by Annex 14

Provisions of the PC1 Procedure

HEMS Seminar 31


Obstacle Clearance – PC1

• The Category A procedures provide non-adjusted profiles (they specify the climb performance required by the procedure – i.e. take-off mass is established by using the WAT graph)

• Only when the Take-off Flight Path (which starts at the point where Take-off Distance Required is established) is specified is account taken of obstacles in the obstacle accountability area.

• Obstacle clearance is specified only in operational regulations (for both PC1 and PC2) and might have to be calculated for each departure.

• To illustrate this a continued climbout pathcontinued climbout path (using the standard climb) is shown against an adjusted TakeTake--off Flight Pathoff Flight Path.

HEMS Seminar 32


HEMS Seminar 33


PC1 Take-Off Using Category A Procedures?

HEMS Seminar 34


TakeTake--off Distance Required (i)off Distance Required (i)

•• TakeTake--off distance required (TODRH).off distance required (TODRH). The horizontal distance required from the start of the take-off to the point at which VTOSS, a selected height, and a positive climb gradient are achieved, following failure of the critical power-unit being recognised at TDP, the remaining power- unit(s) operating within approved operating limits. The selected height is to be determined with the use of Helicopter Flight Manual data, and is to be at least 10.7 m (35 ft) above:

(i) the take-off surface;

HEMS Seminar 35


Category A Clear Area Procedure

Reject distanceTake-off distance

Distance to Vy at 200 ft

200 ft

2nd segment climb

1st segment climb

Vtoss +ROC 35ft

HEMS Seminar 36


Operational Requirement Operational Requirement –– TakeTake--off Distance Required (ii)off Distance Required (ii)

• Take-off distance required (TODRH). The horizontal distance required from the start of the take-off to the point at which VTOSS, a selected height, and a positive climb gradient are achieved, following failure of the critical power-unit being recognised at TDP, the remaining power- unit(s) operating within approved operating limits. The selected height is to be determined with the use of Helicopter Flight Manual data, and is to be at least 10.7 m (35 ft) above:

(i) the take-off surface; or

(ii)as an alternative, a level defined by the highest obstacle in the take-off distance required.

HEMS Seminar 37


Short Field Procedure – Low obstacle

35 ft

RejectTODRH

200 ft

Reference Highest Obstacle

Exact location of obstaclenot important (provided itis beyond reject distance)

TODAH

HEMS Seminar 38


Example RFM Procedure (Cat A Take-Off) – Lower Obstacle

HEMS Seminar 39


Short Field Procedure (Class 1) – Higher Obstacle

35 ft

RejectTODHR

200 ft



TODAH

HEMS Seminar 40


Example RFM Procedure (Cat A Take-Off) – Higher Obstacle

HEMS Seminar 41


Helipad Procedure – Higher Obstacle

35 ft

TODHR

200 ft



TODAH

HEMS Seminar 42


Example Procedure (Cat A Take-Off) – AW139

HEMS Seminar 43


Example Procedure (Cat A Take-Off) – Bell 427/9

HEMS Seminar 44


Elevated Helipad Procedure

200 ft

TODHR

35 ftReference Highest Obstacle


TODAH

HEMS Seminar 45


Helipad Procedures – Obstacle Clearance in the Back-up

• When the back-up procedure was first produced, there was an assumption that it would be used on an elevated helipad with clear space around

• With the advent of a back-up procedures for a ground level site, and the use of elevated heliports located in a rich obstacle environment, came the need to provide guidance on obstacles clearance in the back- up area

• As guidance was not provided in AC 29-2C, it was left to operating regulations to fill the gap - the following text results from the introduction of rule material into JAR-OPS 3 permitting obstacles in the back-up area (the assumption before NPA-38 was that obstacles would not be permitted)

HEMS Seminar 46


Helipad Procedures – Obstacle Clearance in the Back-up

• The profile of each of these manoeuvres has to be considered in establishing obstacle clearance.

•• In the backIn the back--upup; the pilot has few visual cues and has to rely upon the altimeter and sight picture through the front window (if flight path guidance is not provided) to achieve an accurate rearward flight path.

•• In the rejected takeIn the rejected take--offoff; the pilot has to be able to manage the descent which permits a landing on the FATO - whilst ensuring clearance from obstacles.

•• In the continued takeIn the continued take--offoff; the pilot has to be able to accelerate to Vtoss whilst ensuring a 35ft clearance from obstacles.

HEMS Seminar 47


HEMS Seminar 48


PC1 En RoutePC1 En Route

HEMS Seminar 49


PC1 EnPC1 En--RouteRoute

• En-route Performance requires the satisfaction of one of three requirements:

• IMC; an OEI rate of climb of 50ft/min 1000ft above all obstacle (2000ft in the mountains) within 5NM each side of the intended track

• IMC; drift down to a point 1000ft above the landing site avoiding all obstacles by 1000ft vertically (2000ft in mountains) and 5nm laterally

• VMC; drift down to a point 1000ft above the landing site avoiding all obstacles without flying below the appropriate minimum flight altitude (generally accepted to be 500ft).

• Wind effect has to be taken into account• Fuel-dump may be used when complying with specified constraints• Accuracy of navigation has to be within 95%, or the corridor doubled

HEMS Seminar 50


PC1 Landing ProceduresPC1 Landing Procedures

HEMS Seminar 51


PC1 Landing ConsiderationsPC1 Landing Considerations

• Simply described landing at a location has to satisfy two criteria:

• for an engine failure at or before the LDP when the helicopter must be able to perform a baulked landing meeting the obstacle clearance criteria; and

• for an engine failure at or after LDP where the helicopter must be able to land and stop on the FATO.

HEMS Seminar 52


Flight path meetingThe Category A take-off

climb criteriaVtoss & +ROC

15ft

LDPLDP

Cat A Landing Procedure

50ft

Landing Distance

HEMS Seminar 53


Landing Requirements Landing Requirements –– PC1PC1

• Mass does not exceed the MTOM for the procedure being used

• following a engine failure at or before the LDP it is possible to land and stop on the FATO or execute a balked landing clearing all obstacles by a vertical margin of 35ft; and

• following a engine failure at or after the LDP it is possible to land and stop on the FATO clearing all obstacles.

HEMS Seminar 54


Short Field Example Procedure (Cat A Take-Off) – Higher Obstacle

HEMS Seminar 55


Short Field Example Procedure (Cat A Landing) – Higher Obstacle

HEMS Seminar 56


Landing Requirements Landing Requirements –– PC1PC1

• Mass does not exceed the MTOM for the procedure being used

• following a engine failure at or before the LDP it is possible to land and stop on the FATO or execute a balked landing clearing all obstacles by a vertical margin of 35ft; and

• following a engine failure at or after the LDP it is possible to land and stop on the FATO clearing all obstacles.

• This is not as described in previous versions of JAR-OPS; which would have required almost a flat terrain from 50ft (the equivalent of an aeroplane threshold crossing height)

HEMS Seminar 57


HEMS Seminar 58


Provisions Given by Heliport (Annex 14)

Facilities Given by Annex 14

Provisions of the PC1 Procedure

HEMS Seminar 59


PC1 Landing ConsiderationsPC1 Landing Considerations

• The LDP will be established in the Flight Manual

• Establishment of the LDP is a compromise - for other than clear areas - because of conflicting requirements.

• It has to be at a speed which minimises drop down in the balked landing.

• It has to provide an approach angle that will provide obstacle clearance.

• The approach angle must permit a OEI safe landing (speed & ROD)

• There is a problem with older helicopters as more vertical OEI descents are accelerative (the higher the LDP, the more vertical speed at touchdown)

HEMS Seminar 60


Obstacles in the Approach Sector

LDRHLDAH

50ftLDP

LDP

LDRHLDAH

HEMS Seminar 61


Elevated Heliport Profile Under AC 29.75

50ft35ft

LDP

It is usual for the procedure - including the LDP - to be identical to a non-elevated helipad procedure

HEMS Seminar 62


35ft

Elevated Heliport Profile Under AC 29.75A

50ft

Deceleration Segment (AEO)

LDP

HEMS Seminar 63


LDP ‘N’

LDP ‘N’

Standard Landing Profile

HEMS Seminar 64


LDP ‘N’

Deceleration Segment (AEO)Deceleration Segment (AEO)

LDP ‘N’

LDP ‘N’

Entry GateEntry Gate

Entry GateEntry Gate

LDP ‘0’

LDP ‘0’

LDP ‘25’

LDP ‘25’

LDP ‘10’

LDP ‘10’

LDP ‘35’

LDP ‘35’

HEMS Seminar 65


Planning for Multi Decision Segment

• All LDPs on the deceleration segment have a mass that is the lesser of that required for the balked landing (drop down at an associated airspeed) and ROD at the given angle of descent (at nil wind speed)

• The chosen LDP will be establish (once-and-for-all) from the angle given by the surveyed obstacle clearance – the mass provided by the temperature and altitude.

• This mass may be adjusted at planning to provide a wind-improved increment

• The pilot flies in on the deceleration segment until arriving at the gate – direct view to the touchdown point - and then lets down

HEMS Seminar 66


Helipad Example Procedure (Cat A Landing) – Bell 427/9

HEMS Seminar 69


Multi-Plane Landing Procedure

50ft

LDP level Deceleration Segment

Gate is established where landing point is in view

HEMS Seminar 70


Short Field Procedure (Class 1) – Higher Obstacle

35 ft

RejectTODHR

200 ft


LDP TDP

HEMS Seminar 71


Obstacle Clearance in the Balked Landing / Continued TakeObstacle Clearance in the Balked Landing / Continued Take--OffOff

• Regardless of the mass shown in the WAT chart, clearance from all obstacles in the baulked landing sector has to be shown; this sometimes requires that the landing mass be reduced to improve the climb gradient.

HEMS Seminar 72


HEMS Seminar 73


Category A Extension?Category A Extension?

HEMS Seminar 74


Category A Extension Category A Extension (no requirement to reject)

• Development of more powerful light and medium twins has resulted (in 2005) in a situation where One Engine Inoperative (OEI) Hover out of Ground Effect (HOGE) is possible at MGW/MCTOM.

• This effectively removes the need to re-land if an engine fails early in the take-off or late in the landing manoeuvre thus breaking the link between PC1 and the Category A procedure (which has as an element the limitation on the size the heliport/helideck).

• From TDP obstacle clearance still has to be shown - the Category A profile has therefore to be the basis of the procedure.

HEMS Seminar 75


TDP 30ft

Category A Extension (no requirement to reject)

TDP 30ft + X

Min-dip

Min-dip + X

HEMS Seminar 76


Category A Extensions (adequate visual cues)Category A Extensions (adequate visual cues)

• These extensions are only available with the vertical or back-up procedure

• There is sometimes a penalty when an elevated procedure (with the same profile as a ground level helipad procedure) is certificated - the reject surface is required to be greater because of the reduction of visual cues.

• A heliport is considered to be elevated when 3m above the surrounding area; clearly if a specific elevated heliport has a rich visual cue environment, discretion could be applied by the Authority.

• There is no additional requirement for power reserves if this judgement is exercised.

HEMS Seminar 77


Ground level Heliport Ground level surface requirements

Category A Extension Procedure

Elevated at 3m Elevated surface requirements

Elevated at 30m Elevated surface requirements

HEMS Seminar 78


SummarySummary

• We have examined the requirements of Category A

• We have noted the additional requirements of PC1

• We have investigated Category A extensions

• PC1 has, with the advent of modern procedures, become the most flexible of the Performance Classes

• However PC1 still requires a formality of approach that is not possible for the HEMS Operating Site

HEMS Seminar 79


Any Questions

Helicopter PerformanceHelicopter Performance

Performance Class 1Performance Class 1

Jim LyonsJim Lyons

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Hel Performance