Mufflers for Jets
Almost every day, the residents ofSengkang GRC are forced to pause what they’re doing, as military jets screampast overhead. What’s worse, the location of the town—close to the northeasternedge of the island—means that they must endure the noise for an extendedperiod, as the planes circle round again after making a U-turn to avoid entryinto Malaysian airspace. Such disturbances are especially disruptive given how anincreasingly larger number of Singaporeans now work from home, at least part ofthe time.[1] Someresidents even suggest that the frequency of such incidents may number as manyas 7 flights an hour.[2]
Over the years, I and my parliamentarycolleagues have implored the RSAF to consider various alternatives to theiroverflights: to cluster takeoffs even more,[3] toconsider alternative flight paths,[4] totake breaks in the early mornings[5] orduring exam periods,[6]and to respect quiet hours.[7]The responses, while lengthy and varied, have largely retained the same thrust:that the airforce needs to maintain operational readiness for the good ofnational defense, and that there will eventually be relief after thedecommissioning of Paya Lebar airbase, in 2030.
In the meantime, however, our residentscontinue to experience disruptions to their daily activities. Technology,however, has now offered a tested solution: fin-lined nozzles that can beincorporated into engine design. Much like dimples on a gold ball, this advancein aerospace technology offers potentially quieter jet engines, with minimal reductionsin performance.[8]Other technologies, like micro-vortex generators,[9] acousticliners, and other types of modifications to engine nozzles,[10]also appear to hold promise.
In an earlier PQ response, Minister Ngindicated that the RSAF will continue to monitor such technologies.[11]Will the Ministry be able to provide an update on its monitoring efforts? Arethere any plans to devote a budget toward researching and incorporating noise-reductiontechnologies into military aircraft here? While I understand that defensivecapability and safety considerations[12]should always remain priorities for the armed forces, surely the impact thatachieving such capability on the daily life of Singaporeans should matter too.
[1] Hansard (2021)95(22): Mar 1.
[2] Lim, K. (2020), “Interruption of Daily Life Due to Sounds ofMilitary Airplanes,” Change.org, Aug 13.
[3] Hansard (2020a)95(7): Oct 5.
[4] Hansard (2023)95(105): Jul 3.
[5] Hansard (2020b)95(7): Oct 5.
[6] Ng, K.G. (2020),“RSAF to Have Fewer Flights During PSLE and Other National Exams to Reduce Noisein Estates,” Straits Times, Sep 2.
[7] Hansard (2023)95(101): Apr 21.
[8] Coxworth, B. (2021),“Fin-Lined Nozzles Could Greatly Reduce Jet Engine Noise,” New Atlas,Sep 17.
[9] Saleem, M.,A. Karnam, O.L. Rodriguez, J. Liu & E. Gutmark (2023), “Flow and Acoustic Fields Investigationof Noise Reduction by Micro Vortex Generators in Supersonic Nozzles,” Physicsof Fluids 35(10): 106111.
[10] Liu, X., D. Zhao, D. Guan, S. Becker, D. Sun, X. Sun (2022), “Developmentand Progress in Aeroacoustic Noise Reduction on Turbofan Aeroengines,” Progressin Aerospace Sciences 130: 100796.
[11] Hansard (2023)95(112), Sep 19.
[12] Caron, J. (2021),“Aircraft Mufflers—The Hidden Danger You Need to Know,” FAA Safety BriefingMagazine, Apr 30.
