SAINIK BOARD Registration for Ex-Servicemen in Pune

1.      There are a lot of questions and lack of information about the process of registration of Ex-Servicemen (ESM) with the Zilla Sainik Board at Pune. In this post I explain the following:
•    Why you need to register.
•    The documents you should keep ready before visiting the website.
•    The procedure for registering on the KSB site (Kendriya Sainik Board) 
•    The procedure for registering on the ZSB website (Zilla Sainik Board)
•    The procedure for returning the Identity Card of deceased ESM or Widows
•    The process flow for obtaining the waiver on the PMC property tax. 

2.    Recently the Department of Ex-Servicemen Welfare has notified that all ESM need to enroll online at the KSB website. Note that this is mandatory even if you have registered earlier. I had registered in 2009, but had to go through the online process again. The next step is to register on the state ZSB website. This is required for availing of any benefits from the ZSB like purchase of a car from the canteen, certificates for children's admission, Property Tax benefits etc. For Maharashtra use this link to the ZSB website. The process, although simple enough has its own set of challenges. I have written this blog to try and help make the process smoother, simpler and faster.

3.      An email address and Aadhaar enabled mobile number is a must for registration.

4.     You need to have some scanned documents ready on your desktop Some Naval officers do not have the 'passport-type' of Certificate of Service, and must apply to the respective Service HQ to get this done. The following scans are required in pdf or jpg.
File size is minimum 200 kb, and maximum is 10mb, however it is better to restrict the file size to about 250 – 300 kb except some documents like the Discharge book / Service extract that have multiple pages. 
·    Photograph (identity card type with blue background for ZSB) 
·    Masked Aadhaar (can be saved as a screenshot of the downloaded document from a PC). You should upload the Masked Aadhaar as it is, because the file is password protected
·    PAN Card
·    Discharge book/ Certificate of service in booklet form, scanned and put into one file.
·    Documents regarding Gallantry Awards if applicable
·    PPO with wife’s name and date of birth (SPARSH PPO is good). 
·   Pension passbook first page (if available else pdf or screenshot of the statement page showing bank details). 
·    ECHS card (front only)
·    ESM identity card if already issued by ZSB 
·  School leaving certificate from a School located in Maharashtra OR Domicile certificate in Maharashtra for 15 years after retirement (Needed to apply for benefits for Maharashtra domiciled ESM). This rule is not specific to Maharashtra, but each state has the same rules – don’t blame the Maharashtra Sainik Board for this!!
·     Additionally, in case of widow’s registration,   the death certificate of the pensioner.

5.   First visit the KSB website. The process is fairly straightforward. The login ID will be your email address, and you have to set a password. (Keep the password for your email and the password to the KSB website different for security reasons). After completing the registration with all details filled in, download the pdf document that is generated.  The download pdf has to be printed, signed and taken with you when you visit the ZSB. Enter the dependent details here also since you will require an identity card for them too. For ESM, the printed form will show the ESM's face on page 1. There are two sets of documents, therefore.

6.  Once this is done, visit the ZSB website and choose the option for ESM (Select "widow" if that is applicable, and in this case the widow's face will show on the form). (Pro-tip sometimes the OTP takes a long time, and you might need to try multiple times. Go straight down to the ‘Generate OTP’ box and validate the mobile number. Once validated, then you can start entering the other details from the top like name, service details etc). The website generates a two-page pdf that you need to download and print. Subsequent log in is by an OTP on your mobile number. 

7. Carry the three printouts, the originals and a photocopy of all the documents that you have submitted online, and visit the Zilla Sainik Welfare Office on the 4th floor of the New Administrative Building  https://maps.app.goo.gl/PTHVfvU4oKvR53gE9

8.  There is a working lift to the 4th floor (the extreme right side lift does not go to the 4th floor). At one of the two windows at the Sainik Board, you need to verify the copies with the originals. 

9.  For the ESM (and dependent) identity card, the photo has to be stamp sized with a blue background. For widow's ID card, it is a red background. See later on in this blog for some points regarding widow registration.

10. Once you emerge victorious from the visit, you have to wait until your identity card is ready. This confirmation is on email / SMS. It took just three days for me. After this is done, you can apply to claim the PMC Property Tax exemption (as per eligibility). Issue of the ESM / Widow ID card is only after verification. Applying for property tax exemption application will be permitted after collecting the card.

11. Property Tax process. Carry a printout of your property tax bill which looks like this. At the ZSB you have to purchase two forms from the counter and fill them in. Carry loose change, about 5 to 10 rupees.  There is one pink application form on which the ZSWO signs and returns to you for submission to the PMC (a sample is here, but you need the original). The white form is actually your application to the ZSWO for the exemption, and you can see it here if you like, but they will give you the whole set so don’t print it- the forms are updated from time to time. I have provided links to both, so you have an idea of what information is required. Take a photocopy or scan of the pink form once signed by the ZSWO for your record. 

12. Before visiting the PMC for exemption, check this form to see the information required. There are updated forms available at the PMC. Carry the following to the PMC Office:-
•    The Pink Form signed by the ZSWO.
•    A photograph of the claimant to be pasted on the form.
•    Copy of the PPO.
•    Copy of the Service book, to include the page where Sainik Board endorsement. So take a fresh photocopy after the endorsement of your application for property tax rebate is made.
•    Copy of your Property Tax bill.
•    As always, never forget to carry copies of your Aadhaar and PAN to any government office !!!
Take a photocopy of the form and get acknowledgement at PMC. If not possible, then take a scan / photo of the submitted form with the PMC stamp.

You should visit Room No 18 on the ground floor, next to the ATM. If you enter from the main gate, the ATM / room is located on your right as you enter the central lobby. The person will check your documents, and ask you to submit the forms at the registry.  The process takes some time, but if everything is okay, your next property tax bill will reflect the changes. I was asked not to pay the bill generated in April, since the rebate will get factored in once your application is processed.

13.  Widow registration. During registration in the KSB, select the option for Widow. The online form that is download will have the widow's photograph on it, instead of the pensioner's photograph. In order to get a widow’s identity card you have to return the ESM I card. For this, fill out a form and submit the deceased ESM's identity card at the ZSB. Download and print and fill out the form located here. For widow’s application, the stamp sized photo (2cm x 2.5 cm) is with RED background. This form is not needed if you are registering as widow and want and ID card directly. This means, if you select ‘Widow’ in the registration, the form is not needed. If you are applying afterwords, then two photos are needed (one on the form and one for the card).

14. Dependent identity cards. There is a form you need to print and fill out. Stamp size photos are in blue background. You could download a copy from here. You need to carry two photos, one on the form and one for the card. The dependent or widow's name will be entered on the ID card exactly as it is in the PPO. Any corrections must be taken up with the Service HQ. 

15. Timeline for issue of the ID cards. On the first visit, the application is scrutinised at the counter, and you will be given back one form with a number written on it. Keep this safely. At this time, the ESM / Widow is not required in person in cases like difficulty in going outdoors due to health, and the form can be submitted by a relative too. You will get an email from the Sainik Board that the card is ready / application is approved. Keep checking your spam folder too. The card has to be collected in person, because a thumb impression is needed. Carry your Service Certificate  / discharge book in original for this, and also for the property tax exemption application. The staff are quite efficient and the pink form is usually returned to you duly signed the same day.

16.  Other facilities like admission certificates etc. 
•    Information on other services / facilities for ex-servicemen are put up on the notice board at the ZSB Office. This includes monetary awards, scholarships etc.
•    I have not gone through the process for other applications like scholarships, ESM certificates for children recently, hence, I cannot help in that aspect. 

17. Sewa Centre. In the adjoining building within walking distance right behind the ZSB office there are a few ESM owned and privately run Seva Centres that can help with all the paperwork/ photocopies and they seem to be able to handle a lot of services like application for Canteen cards, ECHS cards, education and others. Paid parking is available there.

18. In case there is a delay of more than a year after moving to Pune,  you will be asked to submit a form stating that you have not applied at any other Sainik Board. Similarly, if you are moving your registration from a different state to Maharashtra, then you need to get the paperwork for 'porting out' from the earlier place of stay.

19. Transfer in from other ZSBs within Maharashtra or from other states. When moving to Pune (or for that matter from any ZSB to another), submit your ID card, get a surrender certificate mentioning the reason being a transfer to say Pune. If you have taken property tax exemption at that location, you have to get that cancelled, NOC issued. Now repeat the process of registering at the KSB and new ZSB including printout of the forms etc. Take all these to the new place of residence and submit them for issue of the new ID card. It has been informed that the domicile requirements are for the state, so if you are shifting to Pune with a domicile of another city in Maharashtra, then you will remain eligible for the Property Tax exemption.

I hope this helps to some extent in visiting the office, and being prepared so as to avoid making multiple trips. 

Do comment, and also update in the comments section if you have any experience that I can add here to help others. I frequently update the blog based on feedback. A sign-in is not required to post a comment.
 
Jai Hind!  

How to make a Will - A five-part blog post

 

 

🔼HAVE YOU MADE YOUR WILL?🔼

This blog has been re-done as a 5-part series of posts. This was because the contents grew to cover a large number of topics possibly making it difficult to go through in one reading. The contents have been suitably arranged in a particular sequence.

An MS Word template for a Will is also given in the last part, Post 5 of 5

The complete indexed list of links is below.

Make your Will now – Part 1 of 5

Key terms in Making a Will- Nominations Beneficiaries Part 2 of 5

Drafting a Will - Guidelines and tips Part 3 of 5

Without a Will - Burdens on your loved ones after you pass -Part 4 of 5

Living Will or Advanced Medical Directives - Post 5 of 5

-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-

 

DGCA India Airworthiness Directives on the ALH Dhruv civil variant

Here is a list of all the  Airworthiness Directives issued by  DGCA India for the Civil variant of the ALH Dhruv (2008-to 2023). Source - DGCA website

Note. This article should be read in conjuction with my two other posts,  here and here. This post basically lists all the Airworthiness Directives issued by the DGCA India, after a serious accident or incident on the helicopter comes to light. It might not make too much sense just going through the list as it is. 

At the end of the article there is an analysis of what the ADs imply, and also about the CPA (Collective Pitch Anticipator) referred to in my articles.

 

Airworthiness Directive (AD). A regulatory document which identifies aeronautical products in which an unsafe condition exists, and where the unsafe condition is likely to exist or develop in other aeronautical products of the same type design. It prescribes mandatory corrective actions to be taken, or the conditions or limitations under which the aeronautical products may continue to be operated. The AD is the  common form of mandatory continuing airworthiness information mentioned in Annex 8.

Source: ICAO Doc 9760 - Airworthiness Manual

(Thanks to Commander MK Singh for compiling this list. He has extensive flying in the Navy and Civil aviation. He is a crusader for safety in helicopter flight operations and part of the working group of the VAST under VAI) 

An important point to note is that as per the AD there are just 13 civil Dhruvs, and there are so many ADs. There would definitely be many more such equivalent Directives issued for the military helicopters numbering over 300, but are not in public domain.

01 Jul 2008 
 

1.  AD 001- On one of the DHRUV helicopters, during inspection of IGB area, a crack was noticed. Since an unsafe condition has been identified that is likely to exist or develop on other aircraft of the same type design, this Airworthiness  Directive is being issued for visual inspection and submit the compliance certificate to Certification and Airworthiness Group of RWR&DC, HAL, Bangalor

2.  AD 002 - Crack was noticed at the bolt head of five bolt-blade fork (big) of two DHRUV helicopters.

3.  AD 003 -  Hydraulic System – 1 pressure and fluid loss was reported on one of the DHRUV helicopters. Likely cause of the leak was attributed to the rubbing of hydraulic hoses with LH TGB fairing.

4.  AD -004 -  On one of the DHRUV helicopter, there was an in flight warning for collective pitch anticipator (CPA) redundancy failure for engine-2. During check CPA connector was found to be loose. As a result of this, loss of CPA input to the FADEC has resulted and caused failure of CPA redundancy for engine-2.

5.  AD 004 - On another DHRUV helicopter, there was a warning for CPA failure on both the FADEC when collective pitch was lowered after touch down. On investigation, it was observed that the CPA input to both FADEC was out of range. Further it was found that CPA moving end check nut was loose and tab washer used for locking the check nut was bent incorrectly. These factors had contributed to the CPA rigging disturbance and were the cause for the snag.

6.  AD 004 - There was an in-flight power loss warning followed with large split in NG, TGT and torque parameters of the two engines. Investigations with diagnostic PC revealed that FADEC2 had logged CPA failure. On checking CPA circuit, one wire on the flying lead of CPA was found cut at about 4 inches from the connector due to sharp fold in the CPA flying lead.

02 Mar 2009

7.  AD 009 - Rotors Flight Control – Rotor Control – Marking on cyclic stick, trimming of L-angle of separator wall, provision of additional safety and modification of fork assembly.

 1. To facilitate proper placement of rigging tool on cyclic stick during rigging, a marking on cyclic stick is provided.
2. Trimming of L-angle to clear interference with hydraulic tube bushes.
3. Added safety by introduction of split pin.
4.  To increase clearance between FDR/CVR potentiometer as well as coll pick off fixed end and fork assembly by decreasing the lug width of fork assembly

8.  AD 010 - Stabilizers – Vertical Stabilizer – Installation of web stiffener on front spar of fin torsion box assembly. To reinforce the front spar of fin torsion box assembly, as per board of inquiry recommendation.

9.  AD 011 - During flight when HF transmission is on, amber light of tail rotor vibration warning system flickered. To rectify problem it was proposed by RWR&DC to replace the existing velocimeter Model No 7310 with velocimeter Model No. 8866-1 having improved EMI/EMC shielding.

16 Feb 2010

10.  AD 012R 1 - Rotor Drive (s) –Gearbox(es) – One time check for presence of water in MGB lubricating oil of Dhruv helicopter IDS assembly.

A case of water ingress into IDS assembly on one of Dhruv helicopter  was noticed in 2006. Detailed investigation revealed that water ingress into Main Gear Box was through top cover (p/n: 201P620H 0000 207) of IDS. It was also observed that non-standard “O” ring was used, which resulted in improper sealing against water.

 Usage of correct size “O” ring as per drawing was emphasised and as an improvement sealing of top cover using sealant was introduced as additional feature against water ingress.

 A recent case of water ingress has come to notice on one of Dhruv helicopters. Preliminary investigation revealed existence of a connector on IDS inspection cover (p/n: 201P 636H 0006 201). This inspection cover, with connector on it, is not a standard part as per SOP. Further, the “O” ring of the top cover was found damaged. It is possible that IDS with such inspection cover and damaged “O” ring installed on top cover might have led to seepage of water into MGB of IDS.

The water presence in lube oil of IDS has very serious effects like corrosion.

11.  AD 013R 1 - NAVIGATION – Dependent Position Determination – Design improvement in GPS antenna bracket.

1. On some of the Dhruv helicopters, incidents of GPS antenna along with bracket and connector breaking away from main structure during flights were reported.
2. Investigation by Failure Review Board attributed the failure of sheet metal antenna bracket to its inherent strength deficiency. Replacement of existing GPS antenna bracket with machined bracket was recommended.
3. Part breaking away from aircraft during flight may cause injury to person  or damage property on ground.

12.  AD 015R 1- TAIL ROTOR DRIVE – Gearboxes – Installation of modified parts of AGB assembly to control the interfacing tolerance for avoiding low lube oil pressure.

Controlling of the interfacing tolerance of AGB assembly (P/N 201P 655H 0000 001) parts to avoid internal leakage and to overcome low lube oil pressure of ALH AGB assembly.

01 Apr 2010

13.  AD 016 -  Cracks were reported on two TRA flange assemblies.

HYDRAULIC POWER – Main – Additional inspections of tail rotor actuator (TRA) flange assembly for crack.

20 Aug 2010

14.  AD 017R 1 - Collective eye end of UCS connecting rod were found broken on two Dhruv helicopter after their forced landings

ROTOR (S) – Rotor heads(s) – One time check on connecting rod assemblies (UCS) for crack detection.

15.  AD 018 -  Crack was noticed at threaded area of bolt-blade fork (big) on DHRUV helicopter.

Rotor (S) – Rotor BLADES – One time fluorescent dye penetrant CD check on bolt blade fork (big) - MRB.

16.  AD 019 - Free play of approximately 5 mm was observed on TRA assembly during 1000 hours inspection. Based on detailed inspection and study, vendor has identified that “PINs”p/n 3101-010 used on TRA p/n 3101-000 from serial number 40 to 145 are not heat treated to the drawing requirement. Existence of this condition significantly reduces the fatigue life and may lead to loss of directional control.

HYDRAULIC POWER – Main – One time check on tail rotor actuator

02 Nov 2010

17.  AD 020 - Crack was found during inspection on LH side of horizontal stabilizer mounting bracket fitted on vertical fin spar and IGB rib.

STABILIZER – Vertical stabilizer – One time check for crack on IGB rib on fin torsion box assembly & tail boom assembly AFT

09 June 2011

18.  AD 021 - Engine oil leakage was reported by pilot after last flight. On inspection, rear bearing lubricating oil pipe (return line) found damaged.

AIR CONDITIONING – Distribution – One time check on interference of air conditioning tube with engine oil scavenge pipe and modification for introducing improved clearanc

19.  AD 022 - . In some of Dhruv helicopters cracks were observed in IGB rib bottom and associated area of fin torsion box assembly

STABILIZERS – Vertical Stabilizer – Reinforcement of IGB bottom rib and strengthening ofIGB rib in fin torsion box assembly.

04 July 2011

20.  AD 023 - During a sortie on one of the military Dhruv helicopter, at hover, prior to take off, low rotor warning was observed. Helicopter carried out a safe precautionary landing. On further investigation, it was noticed that the fixed eye‐end of the collective pitch anticipator (CPA), p/n 34LL03C502W3290 was detached from the body of CPA. Such failure may affect handling qualities of helicopter adversely.

Engine Controls – Power Control – Inspection of collective pitch anticipator.

02 Sep 2011

21.  AD 024 - In one of the civil Dhruv helicopter, it was observed that the elastomeric bush (p/n201P 636H 3000 201) was seating on the radius of TDS sleeve. This was due to the bearing flange assembly was done towards tail rotor side of TDS support bracket instead of towards FWD side of the helicopter. This wrong assembly may lead to gradual failure of the bearing leading to loss of tail drive power.

TAIL ROTOR DRIVE‐ Shafts – Check of elastomeric bush seating position on tail drive shaft assemblies (Seg.‐3 & Seg.‐4) in situ on the helicopter

27 Feb 2012

22.  AD 025 - The Alert Service Bulletin “One time torque check on mounting bolts of Main Rotor Blade” is issued on the basis of recommendation made in preliminary investigation report on accident to BSF (Air Wing) Dhruv helicopte r VT-BSH (DW63) on 19-10-2011.

This AD, which prescribes/mandates action to be performed on to helicopters as stated above to restore an acceptable level of safety is hereby issued pursuant to CAR 21.3B. TC holder/ Operators are required to comply with the above stated AD within the stipulated time.

23 July 2012

23.  AD 026 - During investigation of some of the incidents of Advanced Light Helicopter (Dhruv) owned by defense forces, it was found that the collective eye-ends of connecting rod assembly were broken.

Since an unsafe condition has been identified which is likely to develop on other Advanced Light Helicopters of similar type design,this Airworthiness Directive is being issued for installation of improved steel eye-ends in place of existing titanium eye-ends to achieve higher fatigue strength.

24.  AD 027 - In one of the civil Dhruv Helicopter, step marks at spline area of input flange of Intermediate Gear Box (IGB) was reported.

25.  AD 028 - In one of the Military Dhruv Helicopter, Pilot observed physical travel of collective lever obstructed at corresponding torque of 72 percent. Defect investigation revealed that the clip assembly connecting FDR/CVR potentiometer to control rod was found displaced by approximately 20mm upward from its designated position.

Introduction of split pins in FDR/CVR potentiometer attachments of cyclic and directional channels.

21 Mar 2013

26.  AD 030 - In accordance with the para 3.3 (v) of GM 21.91 of CAR 21, this
modification is considered as mandatory Major Modification by the TC holder as an unsafe condition has been identified which exists in other Advanced Light Helicopter (ALH)-Dhruv. This Airworthiness Directive is issued

i. To provide visual inspection means for opening and closing of pilot door , co-pilot door, sliding door and hinged doors; and
ii. To provide door opening and locking instructions on clamshell door.

02 Dec 2014

27.  AD 031 - During 500 hrs servicing if a civil variant Advanced Light Helicopter (ALH) Dhruv, it is observed that the cylindrical roller at the input side of IGB was overheated and damaged. This damge is attributable to Oil starvation. The type of failure is considered critical as it may affect drive line from MGB to TGB.

19 Feb 2015

28.  AD 032 - In one of the ALH dent mark was observed on end plate RH side. Aldo dent and erosion on protection strip delamination was observed on TRB. It was found that one screw from TGB fairing RHS-Attachment came out and hit the TRB first then got embedded into plate. This type of failure is considered critical and it may affect both TRB & End Plate.

17 Oct 2016

29.  AD 034 - During 500 inspection change in CT density was observed on collar region of some of the main rotor blades of Dhruv helicopters. This indicates onset of local delamination.

01 Jun 2017

30.  AD 035 - In one of the ALH restrictions of movement was observed in the longitudinal circuit on Main Rotor Actuator(MRA)  and Tail Rotor Actuator (TRA). Restriction on movement of circuit would lead to reduced controllability of helicopter. This type of failure is considered critical and it may affect controllability of helicopter.

19 Oct 2019 

31.  AD 036. Multiple occurrences of abnormal sound/possible surge and power loss of TM333-2B2 engines installed on ALH Dhruv Civil Helicopters along with vibration and jerks in cockpit during flight.

02 Feb 2021

32.  AD 037 - On one of the Military(IAF) helicopter during flight, Hydraulic System-1 Low level warning light came on and helicopter made precautionary landing. On further inspection Crack was observed on the valve body lug of Main Rotor collective Actuator of system-2 and failure of the lug resulted in the leakage of the hydraulic oil from O-Ring interface

13 July 2023

33.  AD 039 - During a routine sortie, Indian Navy ALH MK-III helicopter ditched into water close to Mumbai coast on 08/03/23 where in control loss in the collective channel was noticed during the flight. Post incident inspection control rod body in the collective control circuit was found broken.

20 July 2025

34.  AD 040 - On 5th Jan 2025 at 1230h, ALH Mk-III CG-850 of Indian Coast Guard met with an accident at Porbandar Airport Runway in Gujrat. The ICG helicopter was on a routine sortie and crash-landed resulting in fire and fatalities. Based on Defect Investigation committee recommendation one-time check for crack detection on Non-Rotating Swash plate installed in IDS assembly is mandated. As a precautionary measure, this AD is issued to carry out one time check for Crack Detection (Dye-penetrant method) on Non-Rotating Swash plate of IDS assembly. (FATAL)

My comments on this exhaustive list of ADs.

1. Far too many refer to the CPA (Collective Pitch Anticipator). The problem is listed from 2008 and caused due to incorrect wiring, bad quality of the CPA bracket and so on. Clearly a workmanship issue. Really!!! Does it take so many incidents for HAL to realise there is a problem? My helicopter suffered this failure in 2004, the AD is issued in 2008. It means that there must have been countless more failures in between! 

The fixed eye-end mounting of the CPA on the airframe looked something like this on my helicopter (this is actually an image of a door latch, but is the closest thing I could find because I didn't have a digital camera at that time).

Fixed eye-end of CPA was something like this, replaced with a machined block later on

 

 2. Water ingress into the MGB relates to use of the incorrect 'O' ring. This is only replaced at the OEM, so the operator had no hand in this. Again, it is the quality of workmanship at HAL. Water ingress into the sealed MGB is really really bad news.

3. Instances of the collective eye-end failures. Again a clear sign of vibration being the culprit.

4.  ...identified that “PINs”p/n 3101-010 used on TRA p/n 3101-000 from serial number 40 to 145 are not heat treated to the drawing requirement. This means that unsafe items have been installed at HAL during production. Again, this points to incorrect manufacturing and quality control

5. The AD AD 013R 1 is issued in 2010 and mentions that the GPS antenna bracket flew off. This had happened to a Naval helicopter in 2007, so it looks like HAL waited till 2010 before informing the DGCA only when a Civil helicopter lost its GPS antenna.

6. Rubbing of hydraulic pipelines is again a clear case of bad workmanship at HAL. We had so many pipelines rubbing and wearing out, here is a picture.

Hydraulic pipeline chaffed due to vibrations and unsuitable routing

 

Why you need a CPA (Collective Pitch Anticipator). In a non-FADEC engine, when there is an increase in power demand by moving the collective lever up, the free turbine rpm tends to lag because the fuel governor takes time to sense the transient droop in the turbine rpm before feeding more fuel to the engine. FADEC = Full Authority Digital Engine Control

All FADEC engines (like the ALH, and almost all modern single engines too) use an electronic means of providing an advance information of the collective pitch lever position to the engine. This way, the engine already 'knows' the collective is going up and provides more fuel at a faster rate when increasing the collective. So the CPA is something like the ‘coarse’ control for fuel, and the electronics in the FADEC further adjust the stepper motor to keep the N2 within limits. The opposite happens when reducing the collective and an rpm overshoot is prevented. Mi8 pilots will identify very well with this phenomenon and are used to raising the collective very carefully. This is because, without a FADEC and CPA the N2 and rotor rpm will droop quite a lot before recovering. This droop is called a transient droop, and the CPA essentially reduces it to negligible levels, hence the acceleration on the engine is almost instantaneous with no exceedances. Here is a graph of a generic explanation of the transient droop.

The graph of a transient droop when power demand is applied and then again when it is removed

 

In case the CPA stops sending signals to the engine(s) then an increase in collective will cause the N2 and Rotor RPM to droop, giving a “Rotor Low” audio because the engine is lagging, and there is a large transient droop. This is what happened to me, fortunately we were on ground. Imaging this happening to both engines in the air – There would have been wild swings of the rotor rpm with minor collective movement, and I just would not know why this was happening. The reason? A very badly made bracket which simply came apart.