Docket No: 

### F AA-20 14-04 93 Directorate ID: 

### 2 0 1 3 -SW-0 1 9-AD Disposition Comments

Or ig in a tin g Office T rack in g No.: 

### S POl 703 BO-R Next Step: [?$) FRA OS PRM 

### D These co mm e nt s a re in res po ns e to a n SN PRM



## D N o Co mm e nt s/O nl y Supporti ve Co mm e nt s R ece ive d

- 

### If thi s box i s c h ec ke d , n o s ig n a t ures are requ ire d. No 

### Ha s the r efe re nc e d s ervice inf o rmation bee n r ev i se d s in ce th e N PRM was i ss ued? I f yes, li s t lates t revi s io n and a tt ac h a co py . No te th a t c hanges beyond th e sco p e of th e p rev i o u s l

y publis h ed N PRM11 ·il/ re quir e a n ew n o ti ce. Co ntac t/ he Di rec t o ra te.foca l po int fo r g uidanc e.
In s tru ction s: S ummari ze a ll co mm e nt s by issue ( n o t by com m e nt e r ) a nd provid e yo ur r eco mm end ed r eso lu t ion of eac h i ss u e. All comments relating to the sa me i ss ue should be discussed together
. Do not li s t a ll o f th e i ss ue s fro m one co mm e nter to ge ther. If c han ges to th e AD a r e r e quir e d ba se d on th e co mm e nt s r ece i ved , ex plain why and des cr i b e in de t a il wh at c hange(s) yo u r eco mm e nd
. R e fer en ce F AA -1 R-M-80 40. 1 C Ch apter 9
. IS SUE 1: Se l ec t on e qf th e fo llowing: o th e r 

### If

o th e r . e xpl a in : 

### C larific a ti o n t o th e Di sc u ss ion Co mment e r (s): 

### S i kor s k y Wha t c ha n ge to th e AD acti o n i s r e qu es ted ? 

### Rev i se th e wo rd in g in th e Di sc u ss io n para graph
. Wh y i s th e c h a n ge req u es te d o r h ow is it j u s tifi ed ? 

### To pro v id e a mo re d es cripti ve n a rr ative. Do we ag ree? Pa rti a ll y Ag ree I f YES , we ag r ee beca use Mak e t he f o ll ow in g c h a n ges t o th e AD : I f PARTIALLY AG RE E , we ag r ee w ith 

### so me of th e ed itori a l change s beca u se 

### it provide s cla ri fication o n function of th e sys t e m W e di sagree wit h 

### so me o f th e e dit o ri a l c h an ges b eca use 

### i t pr ov id es d e t a il s no t need e d. Mak e th e f o ll ow in g c ha n ges to th e A D : 

### D i sc u ss ion W e pr opose to a dopt a n ew AD f o r S ik or s k y Mod e l S-92A he li co pte r s . T hi s prop osed AD wo uld r e quire. d e pendin g on the he li co pter 's se ri a l numb e r , in s t a llin g a n M G B fa il e d pump se n sor and vac uum s w it c h w irin g, in s tallin g an MGB o il a ut o by p ass sys te m , ac ti va tin g AMS 7. 1 s oftware to s how a n ew MGB "O l L OUT" v i s u al wa rnin g, upd a tin g the EGPWS softwa r e to includ e a n a ur a l a nnu nciat i o n of a com pl e te o il pres s ur e loss co ndition , a nd in se rtin g an RFM S u pp le me nt int o t he app li ca bl e RFM. Thi s pr oposed A D i s prompte d by o ne accident and one in -se r vice o il lea kage in cident w he r e it wa s di scove r e d durin g s ub se que nt in ves t i ga ti o n s that th e pi lo t f a il e d to act ivate t he bypa ss va lve w ithin 5 seco nd s of th e o il pre ss ure dropping be l ow 35 p s i , as required b y the RFM. Both acc id ent a nd in c id ent invest iga ti o n s found that th e pilot activated th e bypa ss va lve we ll beyond t he 5 se cond s.

T he m a nu a l ope r at io n of t he by pa ss va lve wi thin 5 se co nd s of th e oi l p r e ss ure dropping be low 35 p s i h as proven not to be a rea l i s ti c expec tatio n . Th e MOB fai led pump se n so r and vacu um sw it c h w ir ing i s a sys t e m t h a t w ill de t ec t a lo ss of o il p ump scave nge vac uu m in th e i nput Pa ge l o f 3m o dul e a nd a le rt t h e pil o t if t h e l ow oi l p ress ure i s th e res ult of a fa il e d oi l p ump . T h e MG B o il a ut o b y p ass sys te m e limin a t es th e n eed for the pil o t t o m a nu a ll y sw it c h th e by p ass va l ve w h e n th e o il pr ess ure dr o p s b e low 35 p s i . T h e A M S softwa re up g rade i s t o au to m a t e th e b y p ass va l ve s u c h that it w ill sw itc h int o o il coo le r b y pa ss m o d e a nd t o a le rt th e pil o t th a t th e l ow o il pr ess ur e m ay b e th e res ult o f a fail e d o il pump . Kn ow in g th e l ow o il pr ess ure i s th e res ult o f a fa il e d o il pump and n o t du e t o o il lea k age w ill a ll ow t he p il o t t o sw itc h th e by p ass va l ve o ut of b y p ass m o d e to a ll ow coo lin g of t h e o i l. W he n th e o i l is n o t coo le d , th e h ot o il m ay ca u se the gea rb ox to ove rh ea t. T h e EG PW S softwa re c h a n ge prov id es a n ew a ur a l wa rnin g of a comp le t e o il p ress ure l oss. I f NO , we d o n ' t ag ree b eca u se
ISS U E 2 : Se l ec t on e of t he.fo llowing: 

### If

o th er , exp l a in : Co mm e nte r (s): What c h a n ge to th e A D a c ti o n i s re qu es te d ? Wh y i s th e c h a n ge re qu es te d o r h ow is it ju st ifi e d ? D o we ag r ee? I f YES , we ag r ee b eca u se M a ke th e fo ll ow in g c h a n g e s to th e AD : I f PARTIALLY AGREE , we ag ree w ith b eca u se W e di sag ree w ith b eca u se M a ke th e f o ll ow in g c h a n ges to th e AD: I f N O , we d o n ' t ag ree beca u se

For addit i ona l is sues, double

- click h e r e

Page2of 3Signature Section S ignat ure indicates co n c ur rence w ith this ac ti on. Orig in ating Office Tracking No.: 

### SP O

170380-R

Date

/0-$--14 Date



### C..05

Page 3 of3Sikorsky s upp o r ts the iss u a n ce of the A D
. but ha s th e fo ll ow in g clarificat i ons in red it a li cs:

·· Di sc u ss io n W e pr o p ose to ad o pt a new A D f o r S i k o r s ky Mode l S

- 92A hel icopte rs. T h i s p ropos ed AD wo ul d re quire , d e pe n d in g o n th e h e li co pt er's se ri a l num be r. in stalling a n MGB fa i l e d pump se n so r and v a c uum sw it c h w irin g. in s t a lli ng a n MGB o il a ut o bypass sys te m. ac ti va tin g AMS 7.1 so ftwar e to s how a new MGB " O IL O UT " v is u a l wa rning. updatin g th e EG PW S so ftwar e t o inc lud e a n a ura l a nnun c ia ti o n o f a co mplet e o i l pre ss ur e l oss co nditi o n. a nd in se rtin g a n R FM S upp l e me nt into th e app li cabl e RFM
. Thi s pr o p ose d A D i s pro mp ted b y o ne accide nt a nd o ne in

- s e r v i

ce o il leaka ge in cide nt in th e 

### 20 08

- 2 00 9 tim ef ram e w h e re it was di scove red durin g s ub se q ue n t in ves ti ga t ions th a t t he p il o t fa il e d to ac t ivate th e b y pa ss va lv e w ithin 5 seco nd s of the o il pre ss ur e dro ppin g b e l ow 35 p s i. a s re qu ir e d by the RFM
. B o th acc id e nt a nd in c id e nt in ves ti ga ti o n s f o und th at the pil o t ac ti va ted th e by p ass val v e' e ll be yo nd the 5 seco nd s.

T he manu a l o per a ti o n o f th e by pa ss va lve w ithin 5 s econd s of the o il pr ess ure dr o ppin g bel ow 35 p s i ha s pr ove n no t to be a rea l is ti c ex pec tati o n . The MGB fai l e d pump se n sor and v a c uum sw itc h w ir in g is a sys t e m that w ill detec t an o il pre ss ure drop a loss o.f oil pump scav e nge va c uum in th e in put mo du l e a nd a ler t th e pil ot if th e low o i l pre ss ure loss o.

f va c uum is the re s ul t o f a fa il ed o il p um p . T he MGB o il aut o b y p ass sys t e m e limin a tes t h

e n eed f o r th e p il o t t o m a nual l y sw i tc h the by pa ss va l ve w hen th e o i l pr ess ur e dr o p s b e l ow 35 p s i
. Th e AMS so ftw a re up g ra d e is to a ut o mat e th e b y pas s va lve s u c h t ha t i t 11'ill s wit c h int o oil coo le r bJp a ss m o de a nd to a le tt the pi l o t that t he l o vr o il press ure loss o.f p ump sca 1 ·e n ge va c uum ma y be t he res ult o f a f a il e d o il pum p. Kn ow in g th e low o il pre ss ure loss of vac uum is th e r es u lt o f a fa il e d o il pump a n d n ot du e to o il l eakag e w ill a ll ow t he p il o t t o sw it c h th e bypass va lve o ut o f by p ass m ode t o allo w cool ing o./' t he oi l. When th e o il i s n o t coo l e d. th e ho t o il m ay ca u se th e input mod ule s e a ls to fa il a llo wing an eJteess ive am o unt of o il to leak re s ultin g in failure of the M GB gearbox t o ove r hea t . Accor d ing ly , th e RFM re v is i on co nt a in s a p roce dure for a vo id ing th e o v erhea t ing s ituatio n by direct in g th e p i/ o tt o b ring th e e ng in e o n th e a f{ec ted s id e of the p um pfail u re t o idl e, s iOII'in g th e s p eed o_{ th e air c ra f t , a n d e n s urin g th e r e is a s l igh t nose-up pitch of th e air c ra ft. T h ere have been se,. · eral in c id e nt s of a pump fai lu re wh e re th e o il had the p o tent ia l t o rea c h a h igh en o u g h temperature to damage the s eal s . T h e EG PWS so f tware c h a n ge pr ov id es a n ew a u ral warning o f a co mpl e te o i l pre ss ur e l oss . .. The incide nt s menti o n ed were hi g hl y un li ke l y to r eac h the sea l damage , lo ss o f o il. s tage . A n improved input m o dul e lin er pr og ra m h as rep l ace d th e maj o ri t y o f th e fleet and has mitigated th i s iss u e . A dditi ona ll y . the pi l o t w il l see seco nda ry ind i cations (e le vated MGB o il temperature s a n d vapor iza t i o n of the MG B pai n t [o d o r and s m o ke]) pr io r to the temperatures where sea l damage i s li kely. Eve n in the extreme l y imp robable case of comp lete l oss of o il. the MGB is capable of ope ra ti on for a time s uffi cien t to perform an emergency la nd in g.