need for speed

[rakker]

Our new EC-135 P2 + is doing 122 KIAS with 64 % of TQ. All the other 135's of our compagny (T2, T2+ and P2) do plusminus 132 KIAS. The machine is brand new. Should we go back to the factory for a recalibration or could something else be the cause? (btw we have the new IBF installed). Thanks for your input.

[Earl of Rochester]

Have you performed a power check and compared the figures against those published in the flight manual?

Have you checked the pitot tube for debris?

What speed are you recording on the GPS?

Earl

[RVDT]

Being a P2+ it will have ADC 1 and 2.

Cross check ADC's with ICP selector.

Check SW version on VEMD is correct for model. Select via VEMD Test switch - read numbers. Q range is different on scale?

Let us know.

[rakker]

Thanks for the input, I will fly coming Tuesday. I'll let you know the outcome.

[ShyTorque]

Fly the aircraft in close formation (someone qualified) and cross-check ASIs.

[rakker]

I have flown the helicopter today. ASI both sides showing 122 KIAS. GPS speed showing 122 GS no wind. Power check is ok. We do not have a glass cockpit so no ADC on our aircraft. called the maintenance compagny and they said it could be in the efficiency of the rotor system. A speed difference of up to 10 knots. Any ideas? Thanks

[delta3]

I would indeed suspect a "main rotor inefficiency"

Happens a lot with Robbies (both in plus and in minus), and + or - 10 kts is in a possible -be it maximal- range.

If no close formation possible, do the race track : go back and forward on a leg, the average of the GPS will give you the average TAS irrespective of wind.

Good luck.