Thruster88

Easily avoided by not stalling the aircraft.

Yes, we plan to change the valve springs without removing the other 3 cylinders. Less surgery is always better.

I believe all the old piston single engine FAR 23 certified aircraft had to meet the 61knot stall limit. Lots of choice for USA sport pilots with a drivers license who have not been declined a class 2 medical. Only one pax though.

Interesting, I now know the purpose of dorsal fins on aircraft. No Van's RV aircraft have dorsal fins, i guess they want to keep that dna in the family.

The aircraft is a reims cessna f406 twin turbine. Assemetric training gone wrong?

If you watched and LISTENED to blues vid you would know the shot was most likely never encased in epoxy. The key hole borescope may show a simple repair is possible. This area of the aircraft obviously needs very careful consideration to avoid a Rob Holland situation.

I have a friend with a lsa55 jabiru with a gen4 engine about 4 years old and 50 hours total time. Over the last year or so another L2 friend has attempted to resolve a slight roughness in the engine, it seems to occur at cruise rpm. Carburetor, jets, fuel flow, spark plugs, ignition system changed etc have made no difference, all very frustrating. A few weeks ago the owner and I went for another test fly. As we rotated the engine lost power and became very rough. Taxi back in engine running rough the whole time. I got out and flipped the prop over, no compression on one cylinder. Suspected a stuck valve. Five minutes later flipped prop over and very good compression on all cylinders. Later we did a cylinder leak down and all were 76-77. Next we ran the engine up keeping an eye on cylinder head temps, it is very cold atm. After about 2 mins the engine started to run rough. Flip prop no compression on one cylinder. Got leak down test done as quickly as possible, every cylinder 76-77. Repeat two more times, same result, no compression then comes good very quickly. So we Suspected a hydraulic lifter problem. Order parts. Removed rocker cover from problem cylinder and found the big valve spring was broken. Pulled cylinder to check for other damage, none found. We will replace hydraulic lifters on that cylinder and all valve springs in the engine. The valve spring was broken in two places, suspect this happened at two difference times, one break small problem, two breaks big problem. So in a way it was a lifter problem, the little valve spring only is not as strong as the hydraulic lifter. This was on inlet valve. Engine was starting and ideling perfectly. The valve springs are very cheap but this has been a costly ordeal. I post for educational purposes. The valve spring can be seen in three pieces.

Did you have a look at Blues vid? Doesn't look like the elevator ends are removable. Yes everything would be weighed. Start light and keep adding and checking balance.

One of the best channels on YouTube. I have been watching on FR24 and listening to the Fisk controller on live ATC. Looks like about 80% of all aircraft have ADSB which is nice.

Probably have to drill a hole in the side of the control horn and have a look in there with a borescope. Shake some shot out and put some runny epoxy in there.

Yes going the long way always the best option. The increased safety of a track north of canberra with lower terrain and more landing options rather than direct Wangeratta Moruya adds only 21mins to the trip for a 160knot aircraft.

Agree, it is like pilots that say on the ctaf inbound at wombat gully instead of saying inbound 10 miles north West. Only locals know wtf wombat gully is.

FR shows a Beech 33 debonair disappear in that area. Looks like vfr flying low.

The O ring is what does the sealing.

If there had been an engine failure or an almost mathematically impossible double engine failure BEFORE the cut off switch movements it would have shown up on the flight recorder as a reduction in N1, N2. THEY WOULD HAVE PUT THIS IN THE REPORT.

You can replace the oring. Need to obtain correct one from an aircraft maintenance organisation. If you choose to replace the valve then you need the correct thread, there are several similar looking threads in use. Take your valve to the your value to the maintenance shop and they will advise.

In the above video the microphone picks up the sound of the switch movement quite easily. I guess it may be possible to move the switch somewhat more quietly.

A few points. Although not mentioned in the preliminary report, the cut off switch movements were likely recorded on the cockpit audio recorders. There is no mention of any engine change in either engine N1, N2, egt ect prior to the cutoff off switch movements that would have required any pilot memory action. The only pilot actions required at that stage of flight is to retract under carriage and pitch for desired airspeed.

What is hard about buying an aircraft? Selling yes that could be hard but buying? Do tell.

I imagine that in the days from downloading the data from the flight and cockpit audio recorders on the 24th June until the release of the preliminary report on the 10th July the Indian investigation team would have asked many questions about how the fuel cut off system works and how the flight recorder gets information about that system. The language used in the report indicates there was no doubt about what happened.

There is a lot of very high density altitude ops in the USA so it is a no brainer to use a Rotax TURBOCHARGED 916. If I was building a 916 would be my engine of choice and you know how much I like Lycoming.

It is unfortunately plausible that the pilot who asked the question "why did you cut off" was the... I think if there was any doubt about how the data recorders get fuel cutoff switch position or data it would be mentioned in the report. Robinson Helicopter Company now fit as standard equipment in the r66 a cockpit camera system. It was used successfully in an Australian accident that would have otherwise most likely not have been solved. Perhaps such a system should be added to fitted to all aircraft. https://www.atsb.gov.au/publications/investigation_reports/2025/report/ao-2023-051

There are switches with the same function in every aircraft, including the type you are now flying.

*** Air India Preliminary Report *** On 12th June 2025, Air India’s B787-8 aircraft bearing registration VT-ANB arrived at Ahmedabad airport operating flight AI423 from Delhi. The aircraft touched down at 05:47 UTC (11:17 IST) and was parked at the bay 34. The crew of the previous flight (AI423) had made Pilot Defect Report (PDR) entry for status message “STAB POS XDCR” in the Tech Log. The troubleshooting was carried out as per FIM by Air India’s on duty AME, and the aircraft was released for flight at 0640 UTC. The aircraft was scheduled to operate flight AI171 from Ahmedabad to Gatwick with ETD 07:40 UTC (13:10 IST). The flight was to be operated by the flight crew comprising an ATPL holder PIC, a CPL holder Co-pilot along with ten cabin crew. Both pilots were based at Mumbai and had arrived at Ahmedabad on the previous day. They had adequate rest period prior to operating the said flight. The co-pilot was Pilot Flying (PF), and the PIC was Pilot Monitoring (PM) for the flight. The crew of flight AI171 arrived at the airport and underwent preflight Breath Analyzer test at 06:25 UTC and were found fit to operate the flight. The crew is seen arriving at the boarding gate in the CCTV recording at about 07:05 UTC (12:35 IST). There were 230 passengers on board, out of which 15 passengers were in business class and 215 passengers were in economy class including two infants. Fuel on board was 54,200 Kgs and as per the load and trim sheet of the flight, the Take-off Weight was 2,13,401 Kgs (Max. allowed - 2,18,183 Kgs). The take-off weight was within allowable limits for the given conditions. There was no ‘Dangerous Goods’ on the aircraft. The calculated V speeds with available conditions at Take-Off were V1 - 153 Kts, Vr - 155 Kts, V2 -162 Kts. The A-SMGCS replay of the flight was also carried out after the accident. The aircraft was observed departing from the bay 34 at 07:48:38UTC. The taxi clearance was received at 07:55:15 UTC and the aircraft taxied from the bay at 07:56:08 UTC. The aircraft taxied to Runway 23 via Taxiway R4, backtracked and lined up. The take-off clearance was issued at 08:07:33 UTC. The aircraft started rolling at 08:07:37 UTC. As per the EAFR data, the aircraft crossed the take-off decision speed V1 and achieved 153 kts IAS at 08:08:33 UTC. The Vr speed (155 kts) was achieved as per the EAFR at 08:08:35 UTC. The aircraft air/ground sensors transitioned to air mode, consistent with liftoff at 08:08:39 UTC. The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off. In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so. The CCTV footage obtained from the airport showed Ram Air Turbine (RAT) getting deployed during the initial climb immediately after lift-off. No significant bird activity is observed in the vicinity of the flight path. The aircraft started to lose altitude before crossing the airport perimeter wall. As per the EAFR data both engines N2 values passed below minimum idle speed, and the RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC. As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction. The EGT was observed to be rising for both engines indicating relight. Engine 1’s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11 UTC At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”. The ATCO enquired about the call sign. ATCO did not get any response but observed the aircraft crashing outside the airport boundary and activated the emergency response. At 08:14:44 UTC, Crash Fire Tender left the airport premises for Rescue and firefighting. They were joined by Fire and Rescue services of Local Administration. Accident involving Air India’s B787-8 aircraft bearing registration VT-ANB at Ahmedabad on 12 June 2025 General Information 1. Aircraft Type Boeing 787-8 Nationality Indian Registration VT-ANB 2. Owner and Operator Air India 3. Pilot ATPL Holder Extent of Injuries Fatal 4. Co Pilot CPL Holder Extent of Injuries Fatal 5. No. of Persons on board 230 passengers, 10 Cabin Crew and 02 Flight Crew 6. Date & Time of Accident 12 June 2025, 0809 UTC (13:39 IST) 7. Place of Accident Ahmedabad 8. Co-ordinates of Accident Site 23°03'17.8"N 72°36'43.6"E 9. Last point of Departure Sardar Vallabhbhai Patel International Airport (VAAH) 10. Intended landing place London Gatwick Airport (EGKK) 11. Type of Operation Scheduled Passenger 12. Phase of operation Initial Climb Injuries to persons Injuries Crew Passengers Others Fatal 12 229 19 Serious NIL 1 67 Minor/None NIL NIL Aircraft Information Aircraft Model Boeing 787-8 Aircraft Sr. No. 36279 Year of Manufacturer of Aircraft 2013 Name of Owner Air India Limited Certificate of Registration 4475/4 Certificate of Airworthiness 6584 valid subject to the validity of Airworthiness Review Certificate (ARC) Last ARC issued on 22 May 2025 ARC valid up to 23 May 2026 Category Normal (Passenger/Mail/Goods) Total Aircraft Hours 41868 Engine Type Left Hand (LH) GEnx-1B70/75/P2 Date of Manufacture of Engine (LH) 20 May 2012 Engine Sl. No. (LH) 956174 Total Engine Hours/Cycles (LH) 27791:43/4298 Engine Type Right Hand (RH) GEnx-1B70/P2 Date of Manufacture of Engine (RH) 21 Jan 2013 RH Engine Sl. No. (RH) 956235 Total Engine Hours / Cycles (RH) 33439:30/ 6202 The last major line maintenance check as per the Aircraft Maintenance Program was L1-1 and L1-2 check carried out at 38504:12 Hrs and 7255 cycles. The next major check (D Check) was due on the aircraft in Dec 2025. The LH Engine with ESN956174 was installed on 01 May 2025 and the RH Engine with ESN956235 was installed on the aircraft on 26 Mar 2025. There were four CAT ‘C’ Minimum Equipment List (MEL) items active on aircraft as of 12.06.2025. These MELs were invoked on 09.06.2025 and validity of these MEL were till 19.06.2025. These MEL were for flight deck door visual surveillance, airport map function, core network, FD printer. There was a CAT A MEL active w.r.t. Nitrogen generation performance, which was valid till 20.06.2025. There were other Category D MELs/NEFs on the aircraft related to cabin and cargo, the validity of these MELs were also within the due date. All applicable Airworthiness Directives and Alert Service Bulletins were complied on the aircraft as well as engines. The FAA issued Special Airworthiness Information Bulletin (SAIB) No. NM-18-33 on December 17, 2018, regarding the potential disengagement of the fuel control switch locking feature. This SAIB was issued based on reports from operators of Model 737 airplanes that the fuel control switches were installed with the locking feature disengaged. The airworthiness concern was not considered an unsafe condition that would warrant airworthiness directive (AD) by the FAA. The fuel control switch design, including the locking feature, is similar on various Boeing airplane models including part number 4TL837-3D which is fitted in B787-8 aircraft VT-ANB. As per the information from Air India, the suggested inspections were not carried out as the SAIB was advisory and not mandatory. The scrutiny of maintenance records revealed that the throttle control module was replaced on VT-ANB in 2019 and 2023. However, the reason for the replacement was not linked to the fuel control switch. There has been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB. Damages The Aircraft was destroyed due to impact with the buildings on the ground and subsequent fire. A total of five buildings shown in the figure below were impacted and suffered major structural and fire damages. Wreckage and Impact After takeoff, the aircraft impacted the BJ Medical College hostel which is 0.9 NM from the departure end of Runway 23. The Emergency Locator Transmitter (ELT) was not activated during this event. The wreckage, from the first impact point till the last identified aircraft item, was distributed in an area of approx. 1000 ft * 400 ft. A layout of the crash site is shown in the photos attached indicating the significant parts of the aircraft. The buildings at the wreckage site have been labelled alphabetically from A-F in the layout for easy reference. As the aircraft was losing altitude, it initially made contact with a series of trees and an incineration chimney inside the Army Medical Corps compound before impacting the northeast wall of the Building A. The distance between the tree on which the aircraft made its initial contact and the point on the Building A where the aircraft impacted is 293 ft. As the aircraft moved forward, it continued fragmenting and collided with other structures and vegetation. The impact witness marks on the building and airplane indicated a likely nose-up attitude (about 8°) and wings level. The vertical stabilizer (fig. 5) separated from the aft fuselage and came to rest about 200 feet south of the initial point of contact with the Building A. The tail section and the RH Main Landing Gear (MLG) of the aircraft were found embedded in the northeast wall of the Building A while the rest of the airplane continued its forward movement. As the airplane continued its path across the roof of the Building A the right engine struck the concrete water tank structure, separated from the airplane and rested underneath the water tank structure facing a heading of approx. 226 degrees near south west wall of the Building A. The inboard parts of the right wing were found in Buildings A & B and the areas surrounding the buildings. The right-wing mid-section and the outboard section was about 280 feet and 520 feet southwest respectively from the initial point of contact with the Building A. The left main landing gear (LH MLG) and left wing outboard and middle section struck building C, came to rest approx. 345 feet south from the initial point of contact. The left wing middle section of the wing was stuck in the north corner of the fourth floor of the Building C while the left wing inboard section was lying about 670 feet southwest of the initial point of contact with the Building A. The nose landing gear (NLG) was found on the ground about 307 feet southwest from the initial point of contact with Building A. The left engine got separated from the airplane and struck the north corner of Building D at the ground level where it remained and was roughly perpendicular to the right engine resting position, at heading of approx. 326 degrees. The wall was pushed into the building and the northwest building column was damaged such that portions of the concrete were missing and exposing the internal metal rebar. The engine, remaining portions of attached cowling, and the surrounding area were heavily damaged by fire. After the tail section was brought down, the APU was inspected and found intact inside the APU compartment. The APU air inlet door, which was intact, was found open. The fuselage fragmented and sustained thermal damage as it traveled along the northwest faces of Buildings C, D, E, and F with the furthest debris observed at about 765 feet southwest from the initial point of contact with building A. The flight deck area and windshield support structure came to rest at about 650 feet southwest from the initial point of contact with Building A. The flap handle assembly sustained significant thermal damage. The handle was found to be firmly seated in the 5-degree flap position, consistent with a normal takeoff flap setting. The position was also confirmed from the EAFR data. The landing gear lever was in “DOWN” position. The thrust lever quadrant sustained significant thermal damage. Both thrust levers were found near the aft (idle) position. However, the EAFR data revealed that the thrust levers remained forward (takeoff thrust) until the impact. Both fuel control switch were found in the “RUN” position. The reverser levers were bent but were in the “stowed” position. The wiring from the TO/GA switches and autothrottle disconnect switches were visible, but heavily damaged. The weather as per the Meteorological office at SVPI Airport, Ahmedabad at the time of the accident was as follows: Time (UTC) Wind (degre es/Kts) Visibility (m) Wx Cloud Temp (°C) QNH (hPa) Trend 0730 240/06 6000 - NSC 36 1001 Not Significant 0800 250/07 6000 - NSC 37 1001 Not Significant 0830 240/03 6000 - NSC 37 1000 Not Significant 0900 260/06 6000 - NSC 38 0999 Not Significant The Aerodrome Sardar Vallabhbhai Patel International Airport, Ahmedabad is a DGCA licensed airport having a license valid up to 09/06/2028. The ARFF category at the airport as per the AIP is Category 9. Communications After the accident the ATC data was preserved. The replay of ATC recordings data was conducted. Summary of events based on the replay is as below: Time (in UTC) Event 07:43:00 The aircraft requested pushback and startup. 07:43:13 ATC approved pushback. 07:46:59 ATC approved Start up. 07:49:12 ATC queried if the aircraft required full length of the runway. The aircraft confirmed requirement of full length of RUNWAY 23. 07:55:15 The aircraft requested taxi clearance, which was granted by ATC. 08:02:03 The aircraft was transferred from Ground to Tower Control. 08:03:45 The aircraft was instructed to line up on the Runway 23. 08:07:33 The aircraft was cleared for Take-Off from Runway 23, Wind 240°/06 Kts. 08:09:05 MAYDAY call was made by AI171. Flight Recorders The aircraft is equipped with two Enhanced Airborne Flight Recorders (EAFR) part number 866-0084-102. The EAFR are fitted at two locations, one in the tail section at STA 1847 and other in the forward section at STA 335. The two EAFRs are similar in construction and record a combined data stream of digital flight data and cockpit voice information, with both stored on the same device. The aft EAFR receives electrical power from the aircraft’s main electrical system. The forward EAFR contains an additional power source from the Recorder Independent Power Supply (RIPS), a system that provides electrical power to the forward EAFR in the event of a power or bus loss on the aircraft. This allows the forward EAFR to continue to record available digital flight data, and voice data from the Cockpit Area Microphone (CAM), even after power is lost to other aircraft systems. The aft EAFR was located on the roof top of Building A on 13th June 2025. The EAFR had impact and thermal damages to the housing. The wires were protruding from the housing and the connectors were burnt. The forward EAFR was located on 16th June 2025 from the wreckage debris besides the Building F. The EAFR was burnt and covered in soot. The EAFR was still attached to the equipment shelf with part of the connector melted but still connected. The ULB was still connected to the housing and the lithium battery was also attached to the equipment shelf, which was removed later prior to transportation. Both EAFRs were transported from Ahmedabad to AAIB’s facility at New Delhi on 24th June 2025. Like various other cases where the data from damaged flight recorders was downloaded by AAIB after sourcing ‘Golden Chassis’ and relevant download cables from the DGCA and other Accident Investigation Authorities, in this case the ‘Golden Chassis’ (Identical EAFR unit) and Download cables required to download data from EAFR were sourced from NTSB, USA. The items arrived on 23rd June 2025. The download from the FWD EAFR was attempted at the AAIB Lab on 24th June 2025. The CPM was retrieved from the EAFR and found to be in good condition. The CPM was mounted on the Golden Chassis and the raw data was downloaded from the EAFR. The downloaded flight data contained approximately 49 hours of flight data and 6 flights, including the event flight. The recovered audio was two hours in length and captured the event. Initial Analysis of the recorded audio and flight data has been done. The aft EAFR was substantially damaged and could not be downloaded through conventional means. The CPM was opened to inspect the memory card. The damage was extensive. #aviation #travel #safety #safetyfirst #boeing #pilot #flight #BreakingNews

The POSITION of the fuel cut off switches is recorded by the FDR. There has been no talk of any other faults. Seems like an open and shut case.