PDA

View Full Version : Teaching Performance at PPL level


Alex Whittingham
10th Jun 2021, 13:45
Hi all, I'm just going through some PPL questions and am finding that the calculation questions in Performance use factors taken from the old CAA Safety Sense leaflet which is so out of date it refers to ANGRs and Perf E. There is a table of factors for grass etc. which in many cases does not correlate to EU OPS and the present Class B operation. Do you still teach to the factors in the Safety Sense leaflet?

Bushdodge
10th Jun 2021, 15:36
CAP1535, Skyway Code, page 47. The document was last revised in March 2021 so one would hope it is accurate.

Extracts from the Skyway code are given to students in the new UK e-Exams too.

Alex Whittingham
10th Jun 2021, 17:10
Thank you, useful document. Its the factors on page 49 (same as the old safety sense leaflet) that I am trying to reconcile with Class B in EU-OPS, one would have thought they would be the same. The 'general safety factor' on take-off of 1.33 is not something I recognise and some of the surface factors are different. It seems odd to teach one set of safety factors in PPL then another set at CPL/ATPL. Will research further

Edgington
10th Jun 2021, 23:40
The 1.33 take-off factor is referenced in CAT.POL.A.400 for performance class C aircraft, isn't class B Turbo props? Class C is reciprocating engines. The 1.33 then refers to twin engines, but the safety sense is saying you should use those safety factors even for singles or PPL's.
Not sure the other safety factors are different from those mentioned in Part-NCO.

Fl1ingfrog
11th Jun 2021, 00:16
PPL studies have never involved a knowledge of commercial operations. The limitations and guidance for private flights including take-off and landing are found only by reference to the Aircraft Manual/POH. Certain performance data is not available in many aircraft manuals though, especially very early ones, but it is not a requirement to write up an operational limitation as a supplement and have it approved. Amendments to aircraft manuals particularly operating data is sometimes required by the CAA to be inserted as an amendment to the POH.

The guidance given for take off and landing in the old but still current Safety Sense leaflet, in my view, is excellent and has a particular purpose; to act as guidance when, and only when, the aircraft manual does not. The advice is always generic and can be described, at best, as putting the pilot on the safe side of wrong, however never compulsory.

I don't think there are two conflicting standards. The additional limitations imposed for commercial ops are there to deal with the sometimes intense external pressures that a commercial pilot can be subject to.

Edgington
11th Jun 2021, 00:31
PPL studies have never involved a knowledge of commercial operations. The limitations and guidance for private flights including take-off and landing are found only by reference to the Aircraft Manual/POH. Certain performance data is not available in many aircraft manuals though, especially very early ones, but it is not a requirement to write up an operational limitation as a supplement and have it approved. Amendments to aircraft manuals particularly operating data is sometimes required by the CAA to be inserted as an amendment to the POH.

The guidance given for take off and landing in the old but still current Safety Sense leaflet, in my view, is excellent and has a particular purpose; to act as guidance when, and only when, the aircraft manual does not. The advice is always generic and can be described, at best, as putting the pilot on the safe side of wrong, however never compulsory.

I don't think there are two conflicting standards. The additional limitations imposed for commercial ops are there to deal with the sometimes intense external pressures that a commercial pilot can be subject to.
All good points, I would agree with you.
The problem would seem to be the CAA are quoting certain things in the answers to certain questions in the PPL E-Exams. The CAA shouldn't be asking things that aren't in the syllabus or things that aren't referenced in law, that would be unfair.
We were taught to use 1.33 factor for take-off, but it took a while to find where that came from. I was taught in Holland so the safety factor isn't UK only, but must have been referenced elsewhere. Like I said in my answer I think Alex classed PPL as Perf B while they are more Class C, for Class C there is reference to 1.33 take-off factor.

Fl1ingfrog
11th Jun 2021, 01:04
The CAA shouldn't be asking things that aren't in the syllabus or things that aren't referenced in law, that would be unfair.

Well many Safety Sense leaflets are referenced in the various published training manuals that ATOs/DTOs commonly use. There are many issues that a pilot faces that cannot be dealt with by 'law' and has to be resolved by pilot judgement. Law cannot define judgement. A very large number of flying clubs operate at airfields with sloping grass runways and where 1.33 for take-off and 1.4 for landing cannot ever be achieved. Private pilots operate from and regularly visit private strips that can be challenging and to me it is reasonable that authorities provide good guidance. The Australian CAA and the US FAA also provide extensive support material. If all this is to be considered essential reading then why shouldn't the content be questioned in exams?

Alex Whittingham
11th Jun 2021, 11:27
Class C is for aircraft with reciprocating engines and with either an MOPSC of more than nine or a maximum take-off mass exceeding 5 700 kg. Light piston singles and twins would be certified under CS.23 and operated in Performance Class B, a Class for aeroplanes powered by propeller engines with an MOPSC of nine or less and a maximum take-off mass of 5 700 kg or less.

The CAA factors come from pre-JAA days when different Performance Groups A to E existed, the TORA/TODA/ASDA factoring requirements in a modern Class B operation are quite different.

The 1.33 factor undoubtably originates from the old CAA Performance Group E although it may have been retained by EASA for any big piston aircraft still flying commercially. Safety Sense leaflet 07 even refers to ANGRs and specifically mentions Group E.

The Air Navigation (General) Regulations 1993 (https://www.bailii.org/uk/legis/num_reg/1993/uksi_19931622_en.html) said at 10 1. (b) The distance required by the aeroplane to attain a height of 50 feet, with all power units operating within the maximum take off power conditions specified, when multiplied by a factor of 1:33 does not exceed the emergency distance available at the aerodrome at which the take off is to be made.

The whole thing looks a bit out of date to me. Seems a bit odd to be teaching factors at PPL based on a UK regulation that is 20 years plus out of date and then teaching different factors for the same aircraft at CPL/ATPL. Do we know who is in charge of this section of the PPL syllabus at the CAA?

ifitaintboeing
11th Jun 2021, 14:11
which in many cases does not correlate to EU OPS

EU-OPS disappeared when EASA Air Operations was introduced (IR-OPS). Within the UK this has now become Retained EU Regulation 965/2012 (https://info.caa.co.uk/uk-regulations/air-operations/) and associated AMC/GM. Annex IV (Part-CAT) specifies the performance criteria to be applied for commercial operations when operating under this section of the regulation and would be applicable to those studying towards a commercial licence; see CAT.POL.A.300 et seq for Performance B aeroplanes. Applicable regulations when operating Part 21 aircraft non-commercially sit within Air Operations Annex VII (NCO.POL.110) which are somewhat vague.

UK CAA safety factors recommended for private pilots appear to be derived from previous/current AN(G)R 2006 Schedule 1 (found within CAP 393 (http://www.caa.co.uk/cap393)) as published in Safety Sense Leaflet 07c (http://publicapps.caa.co.uk/modalapplication.aspx?appid=11&mode=list&type=sercat&id=21) and duplicated in the CAA Skyway Code (http://www.caa.co.uk/skywaycode).

ifitaint...

BEagle
11th Jun 2021, 15:10
The table labelled ‘performance changes’ on p46 of SkyWay Code V3 shows landing distance factors of x1.1 for ‘1000 ft increase in elevation’ and for ‘10C increase in temperature’, whereas the latest PPL e-Exam workbook has been amended with landing distance factors of x1.05 for these conditions.

The PPL e-Exam Flight Performance and Planning Qs and As have been checked by CAAi against the 1.05 factor and are correct.

I have pointed out the anomaly to the SkyWay code editors.

Alex Whittingham
11th Jun 2021, 15:51
Thank you Beags. What is a PPL e-exam workbook and how can I get one? I have looked on the PPL e-exams page and its not jumping out at me.

Alex Whittingham
14th Jun 2021, 09:27
Found it, thank you

Stuart Sutcliffe
14th Jun 2021, 15:32
Found it, thank you
Can you let us know where you found it, Alex? Pretty please? :)

Fl1ingfrog
14th Jun 2021, 18:13
The PPL e-Exam Flight Performance and Planning Qs and As have been checked by CAAi against the 1.05 factor and are correct.

Why is the above correct and the SkyWay Code V3 table and the Safety Sense Leaflet 07 wrong? It should be noted that the safety Sense leaflet differs from the Code V3 in that it advises the 1.05 factor for, the same tabled conditions, only when landing.

Fl1ingfrog
14th Jun 2021, 18:33
Can you let us know where you found it, Alex? Pretty please? https://www.pprune.org/images/smilies/smile.gif

CAP1535S Skyway Code Version 3.pdf (caa.co.uk) (https://publicapps.caa.co.uk/docs/33/CAP1535S%20Skyway%20Code%20Version%203.pdf)

I think anyone who can find this essential piece of reading deserves some exam credits. However, the code appears. on first scanning, to be well structured, presented and with a bit of development (NOT TOO MUCH) covers all the PPL needs to know (sic).

Alex Whittingham
14th Jun 2021, 18:53
Can you let us know where you found it, Alex? Pretty please? https://www.pprune.org/images/smilies/smile.gif you need to log in to the ppl e-exams site apparently, at which point you find a 'documents' tab. One of my chaps has access, found it for me. See this (http://http://skywise.caa.co.uk/ppl-e-exams-flight-planning-a-workbook/?cat=15)

Stuart Sutcliffe
14th Jun 2021, 19:06
Thanks, Alex! 👍

Alex Whittingham
14th Jun 2021, 19:15
I still have a problem with the 1.33 factor. It clearly was taken from ANGRs in the distant past and follows the old Perf E thing, gross TODR x 1.33 must be less than or equal to EDA, with the logic that perf E was mandatory for AoC operations and advisory for private flights. Anyone operating say a Seneca in the UK on both AoC and private would now have 2 quite different sets of factors to apply, a 20 year old Perf E advisory factor for private and the mandatory Class B factors for AoC ops. Shurely shomething wrong? Also
(1) the ANGR factor is UK only, if we are trying to teach PPL to the EASA syllabus across Europe (as we are) this 1.33 is going to be restricted to UK and a few Northern European nations who still think the CAA is worth following.
(2) over the years the EDA part of it has been forgotten, so now it seems to be applied to what? TORA? TODA? ASDA?

Fl1ingfrog
14th Jun 2021, 21:44
the logic that perf E was mandatory for AoC operations and advisory for private flights. Anyone operating say a Seneca in the UK on both AoC and private would now have 2 quite different sets of factors to apply, a 20 year old Perf E advisory factor for private and the mandatory Class B factors for AoC ops.

No, I've racked my brains on this one and I can't agree with the statement above. For private flights the operator has never been required to operate with any other direction than the POH/Aircraft Manual. The issue has never been the pilots licence whether ATPL/CPL or PPL: what mattered was the flight being either private or for public transport. I can recall numerous occasions when a AOC holder provided a contract of service, with the customer agreement, to provide an aeroplane and recommend a selection of pilots for the customer to choose. The customer now became the 'Operator' and the flight was 'Private. A benefit could allow the flight to take place to/from an airfield, preferred by the customer, at which AOC factoring otherwise would not allow.

For the pilot there was no dilemma: A commercial flight: then they would apply the AOC factoring in addition to the POH manual but if a private flight then it was not necessary. I cannot remember ever the CAA providing operational direction to pilots to apply the commercial factoring figures for private flights other than perhaps some few wise words for PPLs in the Safety Sense leaflet. I don't believe EASA provides anything different but if I'm wrong on that one I will need to eat my googles.

Rivet gun
15th Jun 2021, 11:08
I think the issue is what is being taught for exams. We understand that applying safety factors to the flight manual performance data is (for the most part) mandatory for commercial air transport but only advisory for private flights. The question is why the factors advised in the Skyway code are different from the factors required in CAT.POL.A. given the difference, which document are the PPL exams based on?

Specifically the safety factor applied to take off distance. CAT.POL.A.305 (performance class B) says

When no stopway or clearway available
(b) The unfactored take-off distance, specified in the AFM, shall not exceed:
when multiplied by a factor of 1,25, the take-off run available (TORA);
(This is also reflected in CAP 698 SEP1)

However the Skyway code states general safety factor for take off 1.33

In other respects the documents appear consistent with each other. In particular the factor for runway slope: CAT.POL.A says unless otherwise specified in the AFM, or other performance or operating manuals from the manufacturer, the take-off distance should be increased by 5% for each 1% of upslope. The skyway code recommends a factor of x 1.1 for each 2% of upslope on take off, which amounts to the same thing.

At an ATO it may be that your PART-ORA ATO manual requires the safety factors specified in CAT.POL.A (PART-NCO notwithstanding). In which case the 1.33 factor in the Skyway code (and PPL exams?) could be inconsistent with the ATO manual.

Fl1ingfrog
15th Jun 2021, 13:27
A lot of expertise and knowledge has been provided into this thread. What is absolutely clear is that the only organisations who know where they stand are the AOC operators. The ATO/DTO can set the standard it chooses subject to their manual being approved. So the schools will vary in the setting of standards. As I've already stated in an earlier post: there are many ATO/DTO operating at airfields where AOC standards cannot be achieved. Opinion, however wise, suggesting that the private operator should use the AOC standard, is just that, opinion and somewhat nave.

The discussion cannot be about what happens to be the case within an AOC operations or differently at a ATO/DTO. The question was to do with the PPL aeroplane exam and therefore must be in accordance with private operations. I do not have any knowledge with regard to the content of the current online exams. I can say that the CAA have not asked similar questions in my 30 years as an examiner. The emphasis has been centred on the proper interpolation of the AFM manuals and by reference to the Safety Sense leaflets: e.g. the small print normally detailing the factoring for such as : slope, grass, pressure altitude etc. the 60% applicable to landing on short wet grass. The PPL candidate in my experience often slipped up by not reading the supplementary small print usually set below the tables/graph.. What is clear is that if the question is asked about any factoring outside of the AFM then the specific source must form part of the question. The source must also be one of which it is reasonable to expect the PPL should be aware and have studied. If not then the question is unfair and will give grounds for appeal.

In time, no doubt, there will be a proliferation of publications/software detailing feedback of the actual questions. We shouldn't need to wait too long.