[Username Protected]

Hi all - I have been working on a low level issue with my Phenom 300 and NLG extension for some time now, and noted with interest the odd ELEB Component Service Bulletin that Embraer issued the other day which specifically references this topic.

When I drop my gear, the mains come down and lock green quite quickly, but the NLG takes a consistent 10-12 seconds after the gear is dropped to go from yellow to green. After I noted that this delay is sometimes accompanied by a "thump" with the NLG drops, Embraer suggested a hydraulic bleed and inspection, which they did. It found no issues and did not change my situatioin at all.

My challenge is that I have never flown or even been in the cockpit of another Phenom 300 other than my own, so it is hard for me to know what "normal" actually is on something like this. I posted in follow-up to the ELEB bulletin over on the EJOA boards, and one member commented that his NLG consistently goes green within 1-2 seconds of the MLGs.

Can any of the rest of you P300 drivers give me a sense of your experience with the timing of MLG and NLG locking green after gear deployments, and any other insights that you may have on this topic?

[Username Protected]

I would say that is longer than my 300 which is SN 93.

My main also will lock out first, then I would give a best guess that I will have the NLG locked and green within 4-6 seconds afterword's consistently. I do notice a minor thump at the end, but I wouldn't classify it as loud or big.

[Username Protected]

This is caused by air in the system and needs to be bled, jacked and gear cycled. It can lead to the NLG not extending, requiring emergency extension. It seems to be a Phenom design issue.

[Username Protected]

Yeah, we did all that -- jack the plane, hydraulic bleed, cycle, rebleed, etc. No effect whatsoever on the MLG deploy time...

[Username Protected]

The aircraft I’m flying today does the same thing. Gear down, mains in a few second, NLG “thump” after about 8 seconds. I fly several P300 and this is normal to me.

[Username Protected]

I agree - it becomes "normal" as I see it on many of them in our fleet, but I believe it's a design flaw in the hydraulic system according to engineers I've spoken with. It can be inconsistent as well: it may do it once, then not again for days.

[Username Protected]

This is caused by air in the system and needs to be bled, jacked and gear cycled. It can lead to the NLG not extending, requiring emergency extension. It seems to be a Phenom design issue.

Hey (Username Protected), can you elaborate on this issue? My P300 recently had the gear overhauled and I've had about 12 cycles since re-installation. I noted that the nose gear makes a loud BANG when the gear lever is 1st thrown; I presume this is caused by a load on the up-lock. It also makes a less threatening bang when fully extended.

My concern is from my last flight. We flew a 4.5 hour leg at FL450 and ISA -5; cold gear. When I lowered the gear the two mains went yellow then to the green per normal. However, the nose gear went white "UP" and when the mains turned green the nose turned yellow and never turned green. Needless to say this was not appreciated at the end of a very long flight! As we were on the approach and surrounded by thunderstorms I re-cycled the gear. The next extension proceeded normally; however, I noted that the nose gear did not BANG when the gear lever was thrown.

[Username Protected]

(Username Protected)

according to the AMM a thumping noise on the nose gear is associated with air in the uplock box. Not sure if you have already had your uplocks bled as it is seems to be a common thing on the Phenoms.

Thumping noise during LG extension

Takeoff/Landing

During landing gears retraction and/or extension

Presence of air in the uplock boxes

Do as follows: 1. Bleed the air from the LG uplock boxes (AMM TASK 32-31-05-870-801-A/200 ). If after this action the problem persists, do as follows: 1. Replace the LG uplock boxes (AMM MPP 32-31-05/400 )

[Username Protected]

All,

Furthermore, whenever a delay in landing gear extension or retraction is suspected. Please keep im mind rhe follwing: when performing an extension and retraction functional check on the ground using a hydraulic mule, the nominal retraction time is 12 seconds max and 18 seconds max for extension. The AMM also recomends the follwing as probable causes and fixes for landing gear slow retraction and extension:

1. Failure of Nose landing gear door adjustment. (Re-adjust to proper range)
2. Nose landing gear lubrication
3. Nose strut uplock roller ( free movement when moved manually) proper lubrication
4. NLG retraction Actuator R/R
5. Priority valve R/R
6. Air in the uplock boxes
7. Hydraulic system bleed

[Username Protected]

The previous reply with the AMM instruction regarding the up-lock box bleeding is what I was told as well. It seemed to fix our aircraft, albeit not for very many cycles.