Loss Of Engine Oil Pressure In Flight

[Jamhands]

Company received a service letter from Eurocopter pertaining to an incident involving a loss of engine oil pressure in an EC 120 in flight. (See Below)

 

The point of the letter was to reiterate the flight manual's procedure for a loss of oil pressure in flight. This simply states the pilot should apply the autorotational procedure described for an ENGINE FLAME OUT which includes rolling the throttle to the shut off detent. Any ambiguity about whether a loss of oil pressure should be taken slightly differently than a loss of oil pressure has been straightened out by this service letter from Eurocopter and IMHO they are two very different scenarios.

 

It has always been clear in my head that in the case of a loss of engine oil pressure, entering autorotation and landing immediately is obvious but shutting down a running engine seems like a poor choice. I for one would take my chances and take advantage of any power said engine might produce at the end rather than shut it down pre-emptively.

 

Thoughts?

 

 

 

S;arnnN

SERVICE LETTER

To the attention

of maintenance and

flight personnel CUSTOMER SUPPORT AND SALES DIVISION

40220 Tarnos - France

Tel, (33)(0)5s9744000

Telex 570 042

Fax (33) (0) 5 59 64 74 98

Technical Support Department

Fax (33) (0) 5 59 74 45 34

JSV/CD/ML

Service Letter No. 281 8/1 1/ARRIUS2F

Subject: ARRIUS 2 F

Uncommanded in-flight shut-down following illumination of

engine Low Oil Pressure warning Iight.

Bordes, August 22,2011

 

Dear Sir or Madam,

 

This Service Letter contains the findings of investigations conducted following an uncommanded

in-flight shuldown that occurred on an ARRIUS 2F engine in August 2010 during the final phase

of landing. During a commercial flight, the pilot heard an audio warning signal and noticed the illumination of the red low oil pressure "ENG P" warning light. The pilot confirmed an oil pressure level of 0.1 bar on the VEMD and initiated an autorotation procedure while keeping the engine lever in the "flight" detent. Then the engine shut-down occurred during flare, during the final phase of landing. The pilot performed autorotation with no additional consequence.

 

This engine shut-down was caused by damage to the Gas Generator front bearing which resulted in rotating assembly seizure. The bearing was examined and it was determined that the

bearing damage was due to a loss of lubrication. Further investigations conducted on the engine did not reveal the cause of the loss of lubrication to be found.

 

The purpose of this Service Letter is to remind you that, following illumination of the "ENG P"

warning light, the EUROCOPTER EC120 B Flight Manual requires immediate initiation of the

autorotation procedure as soon as the engine oil pressure level is confirmed as low or nil. This

autorotation procedure necessitates engine shut-down. This requirement is related to the velocity and extent of the engine damage once lubrication is interrupted.

 

Please contact us if you require further information or assistance.

 

J-S. VIGNES

Technical Support Department

SIEGE SOCIAL ET DIRECTION GENEMLE : 645'11 Bordes Cedex - France

16l. (33) 5 59 12 50 00 -Telex 560 928 - Fax (33) 5 59 53 15 12

Brevets Szydlowski - TURBOMECA Soci6t6 Anonyme au capital de 38.553.056 Eu.os - Registre du Commerce et des Soci6tes Pau B 338 481 955

[Three_Per]

The only reason I could see them wanting you to shut down the engine is to avoid possible catastrophic failure due to a loss of oil thus impeding anything close to a successful autorotation. While in their example the engine failure during the flare didn't prevent a successful landing maybe a fire or un-contained engine failure could cause problems earlier on in the autorotation phase.

[Zazu]

This has also come up as a topic of discussion with some of my fellow pilots as well. Be that as it may, you might want to read up on one of the last 2 issues of Vertical Mag( I forget which one) where Paul Spring gives a narrative of why, and why not, he in that exact same scenario did not in fact turn off the engine. Consider the fact that he is an owner it does make for an interesting, and in my humble opinion, a rather positive read.

 

Fly Safe

 

Zazu

[Iceman]

Is there a link available for this article?

[helicopterjim]

he in that exact same scenario did not in fact turn off the engine.

 

Never turn off something that is still giving you life!

[SuddenStop]

while I agree with Jim above, I also agree with three per.

 

Shutting down the engine takes away a variable. In this case a variable that could potentially go south on you and in a position where you cannot recover from changes it produced

 

As PIC you have to continue to evaluate your situation and make your decisions. Be prepared to explain them.

 

I would think if you have zero suitable landing areas, you may want to keep the donkey running, but the donkey might not wanna run long as it thrives on oil to keep it turning. you have to react when the change happens.

If you have a beautiful pristine sandy beach for miles, and you want to not only ensure your successful landing utilizing your rock steady autorotation training you perfected at your last proficiency check, and at the same time want to minimize your employers rebuild costs, then you'll probably choose the engine shut down option.

 

So this brings us to EC's and TM's position considering warranty and liability....what will the engine manufacturer pay for when you keep that stove burning to the end and the engine (+ whatever) is damaged well beyond what was expected if you follow their recommendations.

[helidude]

Maybe the manufacturers should spend more time working on their product's reliability, and less time second guessing a pilot's actions after the shiiiiite hits the fan!

[Three_Per]

while I agree with Jim above, I also agree with three per.

 

Shutting down the engine takes away a variable. In this case a variable that could potentially go south on you and in a position where you cannot recover from changes it produced

 

As PIC you have to continue to evaluate your situation and make your decisions. Be prepared to explain them.

 

I would think if you have zero suitable landing areas, you may want to keep the donkey running, but the donkey might not wanna run long as it thrives on oil to keep it turning. you have to react when the change happens.

If you have a beautiful pristine sandy beach for miles, and you want to not only ensure your successful landing utilizing your rock steady autorotation training you perfected at your last proficiency check, and at the same time want to minimize your employers rebuild costs, then you'll probably choose the engine shut down option.

 

So this brings us to EC's and TM's position considering warranty and liability....what will the engine manufacturer pay for when you keep that stove burning to the end and the engine (+ whatever) is damaged well beyond what was expected if you follow their recommendations.

 

 

Why is the most informed and well articulated post being "down-voted" I would expect that kind of behaviour from YouTube users not from you Vertical. For shame!

[SuddenStop]

Maybe the manufacturers should spend more time working on their product's reliability, and less time second guessing a pilot's actions after the shiiiiite hits the fan!

 

 

are you talking the failure of a bearing from oil starvation? Because I'm not sure anyone has that reliability under control. If you know of anyone who produces an oil free bearing at a reasonable cost please let me know, I wanna invest in that company.

or are you talking about the cause of the low or non existant oil pressure in the first place? that alone could have many many causes not connected to the original design.

[helimat]

It's worth noting that in the EC120 the freewheel unit is in the MGB rather than in the engine like the AS350 and other types, so even a complete starvation of the oil system should not effect an autorotation.