Guess what's worse than a flameout on take off? A flameout on catapult launch from an aircraft carrier

Aug 22 2011 - 7 Comments

A quite embarrassing episode marked the end of MAKS 2011 air show on Aug. 21, at Ramenskoye air base, near Moscow. The Sukhoi PAK-FA/T-50, Russia’s 5th generation fighter plane, was forced to abort take off after suffering a flameout in the right-hand Saturn engine.

As below footage shows, the T-50-2, the second prototype of the stealth fighter (52 Blue), aborts its take off roll  after bursts of flames erupted from the engine.

Deploying the airbrakes and the two drag chutes after reaching a speed of around 60 MPH, Sukhoi’s test pilot was able to halt the aircraft well before the end of the runway.

If the PAK-FA flameout in front of some 200.000 spectators had only a negative impact on Sukhoi’s reputation, similar engine failures can be quite thrilling if they occur to fully loaded planes in dangerous phases of a flight: departure, initial climb, landing.

I took the following picture in the Indian Ocean aboard USS Nimitz (CVN-68) on Oct. 19, 2009. An F-18C (BuNo 165205 Modex 405) belonging to the VFA-86 “Sidewinders” experiences a compressor stall during the catapult launch from CAT number 4. The aircraft is fully loaded with fuel and weapons, and it is taking off to perform an on-call CAS in support of Operation Enduring Freedom in Afghanistan.

Fortunately, the aircraft took off in spite of the loud bang and flames coming out from the port engine exhaust that in the second image seems to be operating without the afterburner.

Here’s the entire sequence of the launch showing the single engine departure.

The compressor surge is a particular kind of compressor stall that occurs when the hot vapour generated by the aircraft carrier’s catapult is ingested by the aircraft air intake thus creating a breakdown in compression resulting in a the compressor’s inability to absorb the momentary disturbance and to continue pushing the air against the already-compressed air behind it. As a consequence, there’s a momentary reversal of air flow and a violent expulsion of previously compressed air out through the engine intake producing some loud bangs from the engine and “back fires”.

The compressor will usually recover to normal flow once the engine pressure ratio reduces to a level at which the compressor is capable of sustaining stable airflow. Some engines have automatic recover functions even if pilots experiencing the surge can be compelled to act on the throttle or, in some cases, relight the engine.

Compressor surges are frequent on U.S. aircraft carriers. Unlike the T-50, that could precautionally abort its take off, carrier air wing airplanes can’t stop their run once it’s started. Fortunately, F-18s are used to take off even if an engine is temporarily unserviceable: this shows once again how rusty Legacy Hornet are sometime tougher than some 4+ or 5th generation “colleagues”.

I don’t know if a PAK-FA would be able to take off after experiencing a compressor surge aboard an aircraft carrier but I know for sure the F-35C (that, along with the other variants has returned to fly last week, after being grounded for an IPP failure on Aug. 3) won’t: it’s an easy-to-fly, single-pilot, 5th generation fighter jet. With a single engine.

  • http://snafu-solomon.blogspot.com/ Solomon

    et tu David? don’t tell me you’ve jumped on the F-35 bashing bandwagon!

    • http://cencio4.wordpress.com/ David Cenciotti

      No, I’m not against the F-35, don’t worry. My last one is a statement of fact rather than criticism :)

  • ZP

    There was some controversy at time when the Navy chose to go with the single-engine F-35. Now I’m wondering why they did.

  • EFApilot

    David is right. going single engine with a so heavy carrier aircraft as the JSF will be, it will cost a lot of losses. Something US and UK navies will pay heavily.
    Moreover, a US Navy task force with just Super Hornet (called also Super Slow) and JSF, will be much less effective that what US Navy had in the past with F-14, F-18, A-6 and EA-6. Slower aircrfat, less payload, less range, less flexibility, less radar range detection and capability to intercept targets. Strange approach

  • http://twitter.com/joberama Jober (@joberama)

    Although at the rate F-35 testing is going, the Ford-class CVNs (and their shiny new electromagnetic catapults) will be in service long before the jet arrives….

  • Anonymous Bastard

    Anyway, if the F-35 is ever delivered to the Navy, it will operate in carriers with magnetic catapults :D

  • Paul Woodman

    Nimitz Class carriers and their steam cats will be in service for another 40+ yrs. So I hope they get that worked out. Flaming out in front of 200,00 is embarrassing ,doing that on a carrier launch can be dangerous for ship & crews.(& expen$ive)