Agusta AW139

[TunaSandwich]

I have a couple of questions about CAT A procedures for the AW139. For reference I am looking at RFM
Supplement 12 Cat A operations,
Supplement 50 6800kg and
Supplement 68 Phase 5 additional functions.

According to supplement 12
"For a Ground Level or Elevated Heliport/Helideck, without obstacles in the
take off flight path, the Vertical procedure with TDP fixed at 35ft can be used."

Nowhere does it say anything about a 20ft TDP option for the Elevated Helideck portion in supp 12. However in supplement 68 it talks about the CAT A takeoff symbology for ELEV HELIPAD which gives a 20ft TDP as default. It would be easy to assume that this option is for the Offshore Helideck Procedure, which uses a 20ft TDP, but the procedure for that in Supp 12 clearly states that a variable PI target should be used taken from the graph given. Therefore the symbology cannot be used as this gives a flat hover PI plus 23% at all hover PI's.

The caution below in supplement 68 comes with no reference and I was wondering if anyone knows more details for its meaning if there is no profile given for a 20ft TDP (except the offshore helideck)

Take-Off Symbology - Vertical Profile

The Take-Off profiles indicated on the PFD are to be used with the fol-lowing Supplement 12 CAT A Operation PARTs:

— HELIPAD - PART A - Ground Level and Elevated Heli-port/Helideck Vertical Take Off Procedure

— SHORT FIELD - PART B - Shortf Field Take Off Procedures

— ELEV HELIPAD - PART A - Ground Level and Elevated Heli port/Helideck Vertical Take Off Procedure

— BKUP HELIPAD - PART C Ground Level and Elevated Heliport/ Helideck Back-Up Procedure

When on the ground after selection of any vertical Take-Off profile the TDP height magenta bug is presented on the Rad Alt tape at the default value of 35 ft (85 ft for BKUP HELIPAD). This value should be modified, as required, for the profile being carried out using the DH rotary knob.

CAUTION

The ELEV HELIPAD displays a default TDP value of 20 ft which is lower than the PART A - Ground Level and Elevated Heliport/ Helideck Vertical Take Off Procedure TDP minimum so requires adjustment.


I'd like to know if anyone knows the correct use for the ELEV HELIPAD 20ft TDP symbology. It would be logical to me to say that it is intended for the Ground Level or Elevated Heliport/Helideck procedure when the elevation of the Heliport/Helideck is at least 15ft above the ground. But this is not mentioned in the RFM as far as I can see.

Thanks for your help.

[Geoffersincornwall]

Power Assurance Checks

Would appreciate some feedback from 139 operators on how often you conduct PA checks. Perhaps you could also indicate if you operate using Cat A profiles.

Thanks

G.

[spinwing]

Mmmm ..

Geoff ...

The company (based in Dubai) I used to work for operated to CatA/Perf1 procedures/profiles ... we used to do a 'Power Assurance Check' on the first start of the a/c every day without fail.

[Whirling Wizardry]

PAC

PAC done daily before first flight. CAT A & B flown dependent upon weather conditions (e.g.20kt crosswind). Default would be CAT A. Operating at/near MAUM on each flight. Offshore flying. Some of the other operators complete their PAC on return from their first flight (no pax on board).

[Geoffersincornwall]

Thanks Spin and Whirly...

... are there any 139 operators out there that don't bother with the PA check?

Would it be more practical to have tabulated data rather than the current graphic style?

G.

[noooby]

If by Tabulated, you mean a data table that says if you have this temp day at this PA and your Ng is X and ITT is Y then you are good, then that has been done already.

CHC (some of the bases anyway) use a table that assumes TQ at 90% for PA check and for given OAT's and PA's lists the maximum allowed Ng and ITT. If you're under the numbers you're good.

I think it is double sided. 100Nr on one side and 102Nr on the other.

There is also talk of (Finally!!!) getting the EPA button on HUMS to work, or to have another solution that will allow checks to be done in flight.

[Geoffersincornwall]

Nooby

Thanks for that. I was suggesting that tabulated data in the QRH may be a lot more practical than an almost impossible to read graph. Home-made tables are, however, problematic unless they are NAA or OEM approved and are in a controlled document.

G.

[Arcal76]

Power checks

We do fly Cat A every day and use 102% for take-off and landing.
We do a power check every 25 hours because the limitations section requires to do a power check every 50 hours.

The limitation section is the law.

The Cat B take-off also call for a power check??? which is a non sense since you are Cat B.

The idea is to follow the trend and the change is very gradual and slow.

If we get close to the limit, a compressor wash resolve the problem generally.

If you want do a daily power check, you are better to do it before the first flight, what is the point to do it at the end of the day.

[Outwest]

what is the point to do it at the end of the day.

So you know it is good to go for the first flight the next morning?

[SFIM]

Shot in the dark I know, I wondered please if anyone had (for reference / training only) the PAC tables for EAPS on and EAPS off, for altitudes up to 2000ft, using 90% TQ, 102Nr ??, as the chart is a pain to use IMO
PM me if you can help, regards

[Max Contingency]

I think that to find out the requirement for a power assurance check you need to start at the top:

Does your aviation authority, require you to operate PC1? If so then you must comply with the RFM requirement for CAT A operations including the limitation that "CAT A Ops are prohibited if your engines don't pass a power assurance" and the instruction in each individual take off profile to " Carry out daily power checks in accordance with ENGINE POWER CHECKS procedure in Part K Common Performance"

I think the inference is pretty clear that you should conduct your daily power assurance prior to operating CAT A that same day.

Having said that, I can see Outwest's point of view. Which power assurance is more valid out of these two:

1. You have the first flight in the morning and a power assurance was conducted after last flight the day before. Technically you can't use that power assurance for a CAT A take off even though the aircraft has not flown since and has probably also had a compressor wash.

2. You have the last flight of the day and a power assurance was conducted that morning. Since then the aircraft has flown 10 hours in a salt laden environment without a compressor wash. Technically you are good to go for a CAT A take off.

[tottigol]

Arcal, that's not what the RFM specifies when flying Cat A operations.

[Outwest]

I think the inference is pretty clear that you should conduct your daily power assurance prior to operating CAT A that same day.

What constitutes a "day"? Pretty sure it is defined as 24 hours. So if I do my PA at 18:00 and the next flight is at 06:00 the next morning is that not the same "day"?

[roscoe1]

I don't mean to hijack this thread but is there anyone out there who regularly uses the cargo hook on their 139 at weights that approach the hooks load limit of 4850 lbs.? I'm curious to know if there are any structural issues related to doing external load work with this helicopter. It was never really intended for this (witness the low weight limitation relative to what the ship can carry). Thanks for any input.

[Max Contingency]

I have flown a few under flung toads in the 139. But I have never seen an aircraft with a decent fuel load that had a disposable anywhere near 2200KG (4850lb).

[Apate]

Definition of a day

What constitutes a "day"? Pretty sure it is defined as 24 hours.

I can't speak for FAA land, or indeed your operation. However all references to "Day" I can find in our Ops Manual and MEL state that a day is a "24 hour period commencing at midnight".

[tottigol]

We flew loads at around 3,100 lbs. Anything more than that and you would have to deal with the minimum weight for flight limitation.

[Outwest]

a day is a "24 hour period commencing at midnight".

Ok, well even if that is the consensus, that means I could do a PAC at 00:30 and it would be valid for the flight at 23:00. Now if the regs said that a PAC is required immediately prior to the first flight of the day then it would mean that.

[NomadicMechanic]

Just coming back to the power assurance checks, I have been reading through the RFM Issue 2, Rev 15 (so my information may be outdated by subsequent revisions) and I have come to the following conclusions but would be more than happy to hear other opinions...

1. SECTION 2, PAGE 2-28 - Take off checks, Cat B take off, step 3 - power checks.
Carry out DAILY power checks in accordance with in-flight power checks procedure in Section 4.

2. SECTION 5, PART A, PAGE S12-A9 - Vertical take off procedure for Cat A ops, step 5 - power checks.
Carry out DAILY power checks in accordance with engine power checks procedure in Part K Common Performance.

3. SECTION 1, PAGE 1-23 - Power Margin Trend Monitoring.
Every 50 flight hours record engine power assurance check values for engine power margin trend monitoring purposes.

Now, from reading this information, my understanding is that for both Cat A and Cat B operations a DAILY power assurance check must be carried out (and passed) before flying and the 50 hour requirement is purely an interval to record figures at for engine trend monitoring purposes.

This is just what I conceive from reading the RFM so please tell me if I am way off the mark as sometimes the Augusta manuals can be a bit ambiguous with regards to their content.

[Geoffersincornwall]

Nomad - you are correct..... and it's Agusta by the way, not Augusta,..... except that now we are Finmeccanica.

I think the difference between Cat A & B in this respect is that if an engine failed the PA check then no Cat A ops are possible. If you can get agreement to operate cat B then in theory that would be possible provided the engine was not below a set margin.

G.