February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1 737 / CFM56-7B Engine Oil Consumption February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2 Engine Oil Consumption Contents Background – Regulatory Requirement – Usable Oil Quantity – Airplane Fuel Endurance – Approved Oil Consumption Limitations FAA Policy – Oil Consumption Limitations Boeing Actions – Revised Oil Consumption Limitations – Response to NPRM Notification Notice of Proposed Rule Making February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3 Engine Oil Consumption Background - Regulatory Requirement FAR 25.1011(b) “The usable oil capacity may not be less than the product of the endurance of the airplane under critical operating conditions and the approved maximum allowable oil consumption of the engine under the same conditions, plus a suitable margin to ensure system circulation.” Thus engine oil consumption rate is limited by the relationship: Usable Oil Capacity > Fuel Endurance x Oil Consumption Rate February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4 Engine Oil Consumption Background - Usable Oil Capacity Tank capacity determined by airplane calibration test Left engine tank has less capacity due to wing dihedral Allowance for 10% expansion space requirement Allowance for unusable volume Margin for engine start-up oil gulping Margin for engine go-around oil gulping February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 5 Background - Airplane Fuel Endurance “endurance of the airplane under critical operating conditions” New airplane performance Optimum cruise altitudes Westbound step cruise capability Sea level takeoff and landing airport Maximum fuel capacity (separate calculation for aux tanks) All fuel used; (200 nm flight to alternate and 30 minute hold) Descent to and missed approach allowances at destination and alternate airports Minimum payload (10% of seating) at 220 lbs/passenger Fuel LHV 18,600 BTU/LB and density of 6.82 lbs/gallon Engine Oil Consumption February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6 FAA Policy - Oil Consumption Limitations • The FAA Seattle ACO has recently changed their compliance policy • Concerned about multiple engine failures due to oil exhaustion - Airworthiness Limitation required to ensure airplanes are not operated with engines that have an excessive oil consumption rate - Limitation would require maintenance or removal of engines prior to exceedance of the maximum oil consumption rate • Required airworthiness limitation during recent type certification programs - 737-900 model - 737-800 model with winglets or winglet provisions - Limitation included in section 9 of MPD • FAA is proposing a NPRM on existing production airplane models - FAR 25.1011(b) oil consumption limitation added to MPD - 737-600, -700, -800 models included Engine Oil Consumption February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 7 Boeing Actions – Revised Oil Consumption Limitation • Boeing submitted revised FAR 25.1011(b) oil consumption compliance data for all the 737NG models on January 18, 2001 - Pending FAA approval – oil consumption limitation will be increased for all commercial applications - Revised limitations still below CFMI maximum recommendation of 0.4 gal/hr Yes 0 10.84 0.33 0.25 737-900 No 0 10.42 0.34 0.25 Yes 0 11.23 0.31 0.25 737-800 No 0 10.75 0.33 0.25 Yes 9 16.3 0.22 0.22 700-700 BBJ No 9 <16.3 0.22 0.22 Yes 4 14.0 0.25 0.25 737-700 No 0 11.62 0.30 0.25 600 No 0 12.09 0.29 0.25 Existing Oil Consumption Limit (gal/hr) Proposed Oil Consumption Limit (gal/hr) Fuel Endurance (Hours) Number of Auxiliary Tanks (PATS STC) Winglets Installed 737 Minor Model Engine Oil Consumption February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 8 Boeing Actions –Response to NPRM Notification Key points: • Existing AMM provides appropriate oil consumption limitation data - Including oil consumption limitation in MPD is not required • From a purely operational standpoint, the continued operation of an engine with oil consumption exceeding the FAR 25.1011(b) limitation does not present an unsafe condition for flight durations appreciably below the maximum fuel endurance of the airplane • The proposed NPRM would require the removal and overhaul of engines that exceed the FAR 25.1011(b) oil consumption limitation - Unnecessary removal of otherwise serviceable engines will increase operational cost to operators who do not use the maximum airplane range capability - Consideration should be given to permitting the use of engines with oil consumption above the FAR 25.1011(b) computed value provided appropriate limitations on either dispatched mission length and/or fuel load are observed Engine Oil Consumption February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 9 Notice of Proposed Rule Making • The FAA will likely publish an NPRM regarding engine oil consumption rates in the US Federal Register this year - Comment period is normally 60 days - Boeing will notify WTT participants when NPRM is published - Operators are encouraged to review the NPRM and submit comments • FAA staff has indicated they would consider granting an Alternate Means of Compliance (AMOC) to allow continued engine operation above the FAR 25.1011(b) limitation - AMOC would be approved for individual operators with the prerequisite of establishing an acceptable oil consumption management plan - Boeing can provide additional data to support an operator’s AMOC request Engine Oil Consumption作者: 979199501 时间: 2011-4-12 14:25:21 标题: 回复 1# 航空 的帖子
